cereal silage crop management: current state of knowledge · [2] the new zealand institute for...

FR SPTS No. 18614

Cereal silage crop management: current state of knowledge

de Ruiter JM

September 2019

THE NEW ZEALAND INSTITUTE FOR PLANT AND FOOD RESEARCH LIMITED (2019)

Confidential report for:

Foundation for Arable Research (FAR)

Client ref: F19/01

DISCLAIMER

The New Zealand Institute for Plant and Food Research Limited does not give any prediction, warranty or assurance in relation to the

accuracy of or fitness for any particular use or application of, any information or scientific or other result contained in this report. Neither

The New Zealand Institute for Plant and Food Research Limited nor any of its employees, students, contractors, subcontractors or

agents shall be liable for any cost (including legal costs), claim, liability, loss, damage, injury or the like, which may be suffered or

incurred as a direct or indirect result of the reliance by any person on any information contained in this report.

LIMITED PROTECTION

This report may be reproduced in full, but not in part, without the prior written permission of The New Zealand Institute for Plant and Food

Research Limited. To request permission to reproduce the report in part, write to: The Science Publication Office, The New Zealand

Institute for Plant and Food Research Limited – Postal Address: Private Bag 92169, Victoria Street West, Auckland 1142, New Zealand;

Email: [email protected].

CONFIDENTIALITY

This report contains valuable information in relation to the Crop Management programme that is confidential to the business of The New

Zealand Institute for Plant and Food Research Limited and Foundation for Arable Research (FAR). This report is provided solely for the

purpose of advising on the progress of the Crop Management programme, and the information it contains should be treated as

“Confidential Information” in accordance with The New Zealand Institute for Plant and Food Research Limited’s Agreement with

Foundation for Arable Research (FAR).

PUBLICATION DATA

de Ruiter JM. September 2019. Cereal silage crop management: current state of knowledge. A Plant & Food Research report prepared

for: Foundation for Arable Research (FAR). Milestone No. 83056. Contract No. 37294. Job code: P/444004. FR SPTS No. 18614.

Report approved by:

John de Ruiter

Scientist/Researcher, Field Crops

September 2019

Warrick Nelson

Science Group Leader, Field Crops – Sustainable Production

September 2019

[i] THE NEW ZEALAND INSTITUTE FOR PLANT AND FOOD RESEARCH LIMITED (2019)

Contents

Contents ........................................................................................................................................ i

Executive summary..................................................................................................................... 1

1 Introduction ..................................................................................................................... 2

2 Systems for WCS production ........................................................................................ 3

2.1 Environmental benefits of WCS in systems ........................................................... 4 2.2 Value of dry matter grown ...................................................................................... 4

3 Planting decisions .......................................................................................................... 6

3.1 Seed bed preparation ............................................................................................. 6 3.2 Sowing date ........................................................................................................... 6 3.3 Sowing rate ............................................................................................................ 7 3.4 Sowing depth ......................................................................................................... 8 3.5 Seed treatment ....................................................................................................... 8

4 Overview of current species options ............................................................................ 8

4.1 Traits for cultivar selection ..................................................................................... 9 4.2 Cultivar selection, silage yield and crop duration ................................................. 11 4.3 Growth stages ...................................................................................................... 12

5 Nutrient management ................................................................................................... 14

5.1 Overview of nutrient management ....................................................................... 14 5.1 Fertiliser requirements ......................................................................................... 15 5.2 Nutrient removal ................................................................................................... 18

6 Weed control ................................................................................................................. 19

7 Insect control................................................................................................................. 19

8 Disease management ................................................................................................... 20

8.1 Overview .............................................................................................................. 20 8.2 Disease control including timing and efficacy of fungicides in cereals ................ 21 8.3 Fungicide withholding periods for WCS ............................................................... 25

9 Plant growth regulators ................................................................................................ 26

9.1 Overview and options, autumn and spring crops ................................................. 26 9.2 Supporting data for PGR chemical treatments .................................................... 26

[ii] THE NEW ZEALAND INSTITUTE FOR PLANT AND FOOD RESEARCH LIMITED (2019)

10 Irrigation ......................................................................................................................... 30

11 Environmental effects on crop growth ....................................................................... 30

11.1 Soil and air temperature ....................................................................................... 30 11.2 Rainfall ................................................................................................................. 30 11.3 Radiation .............................................................................................................. 30

12 Harvest timing and harvest methods .......................................................................... 31

12.1 Decisions on harvest time – yield and quality changes near maturity ................. 32 12.2 Development stage vs physical indicators for harvest timing .............................. 33 12.3 Synchronising harvest timing ............................................................................... 36 12.4 Use of inoculants and chemical additives ............................................................ 37 12.5 Chopping .............................................................................................................. 38 12.6 Cutting height ....................................................................................................... 38 12.7 Quality losses during ensiling .............................................................................. 39 12.8 Stack management .............................................................................................. 40

13 Feed quality ................................................................................................................... 40

13.1 Forage quality indicators ...................................................................................... 41 13.2 Quality of WCS ..................................................................................................... 42 13.3 Validation of ME of whole crop silage .................................................................. 45 13.4 Mineral content and value of nutrients ................................................................. 49

14 Cost of production/margins for WCS and grain crops ............................................. 50

14.1 Autumn wheat for silage or grain ......................................................................... 50 14.2 Spring wheat for silage or grain ........................................................................... 52

15 Summary ........................................................................................................................ 56

16 References ..................................................................................................................... 57

Cereal silage crop management: current state of knowledge. September 2019. FR SPTS No. 18614. This report is confidential to Foundation for

Arable Research (FAR).

[1] THE NEW ZEALAND INSTITUTE FOR PLANT AND FOOD RESEARCH LIMITED (2019)

Executive summary

Cereal silage crop management: current state of knowledge

de Ruiter JM Plant & Food Research Lincoln

September 2019

Cereal production in New Zealand primarily supplies grain for human food grain, animal feeds

and malting, but there is potential to expand the whole-crop cereal silage (WCS) market as a

supplement for pasture-based animal feeding systems. Other uses for WCS include a break

crop in arable systems and in pastoral renewal rotations. Cereals present a good option for

mitigating nitrate leaching in winter and spring. Feed can be conserved as a green chop silage

or carried through for harvest as a grain crop and straw. Details presented in this review cover

the full range of agronomic management for producing high yielding crops with high quality for

conservation. Species, cultivar, sowing date and other factors important for successful

establishment are discussed. Mineral fertiliser and N fertiliser management are strong drivers of

yield potential and profitability, as is the incidence of disease, pest and weed pressure. Good

management practice for biotic constraints are presented with a focus on recent information

from regional New Zealand trials.

The range of quality of cereal crops for ensiling is discussed, and the impact that plant growth

regulators, fungicides, timing of harvest, silage inoculants, crop desiccant, and ensiling

practices have on quality. Potential improvements in quality through crop management is

reviewed, along with differences in the quality of silages made from different species and

cultivars. The issue of low metabolisable energy (ME), as measured by commercial near

infrared reflectance spectroscopy, is addressed and results presented for an in vivo ME

validation in a ruminant digestion study. This showed that ME values need adjusting by

commercial labs to bring WCS into line with competing feeds.

The productivity and profitability of WCS is a key for this crop to be adopted more widely as an

animal feed. Agronomic practices are well developed for cereal grain production and the

methods are easily adopted by WCS producers. Therefore, opportunities for development and

growth of the WCS industry is achievable provided key management practices are followed and

that farmers are made aware of the value of this crop as a supplement in animal feeding

systems. The fit of WCS cropping within existing farming practices is a key to continuing

development as a viable cropping option. For further information please contact:

John de Ruiter

Plant & Food Research Lincoln

Private Bag 4704

Christchurch Mail Centre

Christchurch 8140

NEW ZEALAND

Tel: +64 3 977 7340

DDI: +64 3 325 9475

Fax: +64 3 325 2074

Email: [email protected]




1 Introduction

Whole-crop cereal silage (WCS) is a high fibre feed with moderate energy and protein content.

WCS can be grown well in most areas of New Zealand. Its quality profile complements other

feeds, providing an effective balanced ration with pasture, kale and fodder beet. It is accepted

by all stock classes in the dairy, beef, sheep and deer feed industries with particular suitability

for supplementing animal requirements during pasture flushes or during periods of seasonal

feed deficit (FAR 2013b; Milne et al. 2006; Stevens et al. 2004). Opportunities for increased

future use of WCS are dependent on the demand for feed supply, its suitability and fit for

production systems, the quality of feed produced and its match with nutritional requirement for

stock, and its profitability for the growers (de Ruiter et al. 2007). In addition, as WCS can be

conserved well, there is good potential for using WCS at other times of the year as a

supplement to pasture in times of shortage or for supplementing crops such as kale or fodder

beet for winter feeding (Stevens et al. 2004). Cereals are versatile in that there are many

options for supplementary feeding, including green feed, straw, grain and conserved product

(FAR 2002a). There are other farm system and environmental drivers that warrant

reconsideration of the potential role for WCS in supplementary feeds. These are animal welfare,

flexibility in farming systems including being able to feed the crop as green chop or WCS, and

environmental benefits in reducing excess nitrate losses from urine wastes in farm systems.

The coexistence of arable and dairy systems means there are opportunities for both the arable

and forage industries. The value of cereal silage to the dairy farmer is the comparatively high

quality of feed if grown with sufficient inputs and if conserved well (de Ruiter et al. 2002). For

cereal silage to be used more widely there is a need for high feed quality, consistent methods

for metabolisable energy (ME) determination, stable yield, improved profitability for the grower,

and improved acceptability for the animal.

The Foundation for Arable Research (FAR) levy statistics indicate there are over 130 arable

farmers growing cereals for silage. Estimates from certified seed production of varieties

developed for silage use (mainly forage barley and forage triticale cultivars) show they are

widely used by graziers and livestock farmers. The area of WCS varies between 15,000 and

25,000 ha split equally between green chop and WCS use (FAR, personal communication; MPI

2016). Total production is currently approximately 200,000 tonnes of dry matter off 15,000 ha.

Features of WCS quality include medium to high ME (9.5–10.7 MJ/kg), medium-high soluble

carbohydrates and starch (20–25%), low protein (8–10%), low minerals (Ca, P, Na, Mg, trace-

elements), medium-high neutral detergent fibre (40–55%).

Flexible sowing dates with predictable harvest dates allow harvest contractors to plan for silage

making over an extended period. The window of opportunity does not coincide with pasture or

maize silage. Variable sowing dates can be used to fit crops within a pasture renewal

programme with minimal cultivation.

The potential benefits of increased adoption of WCS for feeding systems extends beyond the

immediate animal feed value and crop production operations. Commercial contractors are

required to handle the crop with specialised harvesting and silage making expertise. This is

already established for harvesting and conservation of pasture and maize in most regions in

New Zealand.




The purpose of this review is to summarise relevant past (pre-2012) research on WCS,

summarise the most recent (post-2012) research, and point to existing resources that offer a

more complete account of the current knowledge in specific subject areas. Relevant FAR

cropping strategy documents have been prepared for (1) nitrogen (N) application in wheat (FAR

2013a) and (2) cereal disease management (FAR 2018). There are a number of Arable Update

and Arable Extra publications providing base information for grain cereals that are also

applicable to WCS crop management. Key points have been extracted from these publications,

and they should be consulted for more detailed data relating to crop management practices.

2 Systems for WCS production

Key points:

WCS provides fibre, energy value of the grain, and roughage factor complementing

fodder beet, kale and pasture diets.

The economic value of WCS is comparable or better than cereal crop production for

grain

Risk factors are low for WCS production in the South Island.

Autumn-sown cereals provide winter cover for land at risk of N leaching loss.

Cereal catch crops established after a winter grazed crop can reduce N leaching losses

when compared with a fallow treatment.

Well-grown WCS is conserved naturally by anaerobic fermentation (enhanced with

silage inoculants) and good practices for ensiling (compaction and sealing).

Account should be taken of the nutrient value of mineral removed in WCS, and the

fertiliser required to restore soil fertility, following WCS.

WCS has a potential strong place in South Island feeding systems where maize is a risky

option, and where there are reliable existing production systems for high-yielding cereals for

grain. However, in the North Island, maize is currently a preferred high carbohydrate/medium-

low protein supplement with a competitive edge advantage over WCS as a dairy feed

supplement. There is opportunity for increasing the integration of cropping and dairy systems

whereby WCS feed is produced on cropping land and transported to dairy farms for the

supplementary feed market. WCS provides fibre, energy value of the grain, and roughage factor

complementing fodder beet, kale and pasture diets. In addition, increased use of home-grown

WCS could lead to reduced reliance on imported feed such as palm kernel or replacement of

straw with a better fibre and energy source for wintering of stock.

Whole-crop cereal silage is best made by direct-chop harvesting of triticale (Triticosecale),

barley (Hordeum vulgare L.) or wheat (Triticum aestivum L.) at the cheesy dough stage. The

material should be well-consolidated and well-sealed in a pit or in wrapped bales. Advances

have been made for ensiling and/or preserving the feed by applying specific fermentation

bacteria or using differing ensiling and preservation techniques, although the added cost of this

technology needs to be balanced against the value of the feed produced and the end use. Well-

made cereal silage has similar energy value to maize but is less risky to produce in regions of

New Zealand that are cooler or more exposed to wind. WCS provides returns for cereal growers

with gross margins similar to those for milling, feed or malting cereals.




2.1 Environmental benefits of WCS in systems

Cereals are efficient users of soil minerals and mineral N, as a result of their fibrous root

system. Their capacity for cool season growth and uptake of mineral N during this period

means they offer an important environmental mitigation option to reduce the amount of

leachable N in winter and spring. Autumn-sown cereals generally do not require N fertiliser for

establishment, with early growth sustained by residual N in the soil. During wet winters the

available N may be reduced through leaching and therefore spring application may be required

to support increasing demand for N. In the 2013–14 and 2014–15 trials additional N was

required in early spring as the soil N was depleted at that time (Arnaudin et al. 2015).

Senescence of lower leaves is usually a good indicator of N stress around the tillering and early

node development stage.

If cereals are sown in late winter and spring after a grazed winter forage, then there are

potential environmental benefits through the uptake of N during early growth, thereby reducing

nitrate leaching. In a wet spring, the potential for N loss is still high but significantly reduced by

the presence of a crop. The use of winter and spring cereals as N catch crops is discussed by

Horrocks et al. (2019).

2.2 Value of dry matter grown

Gross returns from harvesting dry matter for silage are similar to those for grain harvest.

Returns for silage, vegetative feed or grain will vary with seasonal price, local production costs

and yield achieved. Refer to section 14 for consideration of profitability of WCS and grain

production.

The value of WCS as a conserved feed supplement lies in its high composition of readily

fermentable carbohydrate and moderate protein content (de Ruiter et al 2002, 2007). When

supplementing with other feeds such as kale, fodder beet and pasture there is good potential for

adding to the net feed value (Dalley et al. 2017). Questions have arisen recently about the lack

of nutrient balance in main winter feeds such as kale and fodder beet, so there is an opportunity

to use conserved cereals and other supplements to fill the quality gap for adding body condition

to animals or using as a supplement during lactation feeding (Edwards et al. 2014). WCS adds

effective fibre into ruminant diets.

There is a net cost resulting from nutrient depletion through export of nutrients off-farm or

movement of nutrients from one part of the farm to another. This is not usually accounted for in

the economics of silage production. In an example of net nutrient removal in herbage (Table 1),

N and potassium (K) were the main contributors to the total nutrients removed.




Table 1. Comparative nutrient yield (kg/ha) of whole-crop cereals (‘Sapphire’ wheat,

‘Rocket’ triticale, ‘Omaka’ barley, ‘Hokonui’ and ‘Stampede’ oat, in three historical trials

conducted in Canterbury.

Site/Cultivar N P K Ca S Mg Na

kg/ha

Lincoln

‘Sapphire’ 210 32 195 30 21 15 3

‘Rocket’ 126 20 92 22 12 12 2

‘Hokonui’ 172 28 302 33 18 12 20

‘Stampede’ 197 25 296 32 18 12 14

Highbank

‘Sapphire’ 170 15 113 27 13 9 3

‘Rocket’ 170 16 119 36 14 12 2

‘Omaka’ 189 16 142 40 17 11 9

‘Hokonui’ 208 22 176 46 22 17 24

Seadown

‘Sapphire’ 166 12 105 26 12 9 6

‘Rocket’ 209 19 137 47 19 14 3

‘Omaka’ 213 19 145 35 19 12 15

The changes in soil fertility from growing a silage crop are not directly related to the amounts of

fertiliser applied or the net uptake of nutrients during crop growth. The value of nutrients should

also account for nutrients returned to soil in stubble. Organic matter turnover, mineralisation and

release of bound nutrients adds to the pool of nutrients available for crop uptake. Calculations of

the nutrient removal (in fertiliser equivalents) overestimates the requirement for replacement.

Nevertheless, successive seasons of cropping may have a significant effect on the balance of

soil minerals remaining after crop removal. Suggested restorative fertiliser application rates will

depend on the base fertility of paddocks usually measured before sowing (Section 5).




3 Planting decisions

Key points:

Prepare seedbed as for typical cereal grain crops for feed or human use.

Early sowing in the autumn does result in a yield gain.

Harvest date can be advanced by up to 2 weeks when comparing the same cultivar in

an autumn vs early spring sowing. However, individual cultivars will mature at different

rates depending on their genetically determined developmental responses to

temperature and photoperiod.

Sowing rates to achieve desired populations are adjusted for different seed size,

seedling survival and potential for tillering. Generally, 300 plants established per m2 will

ensure an optimum leaf area index and achieve near-maximum yield potential.

3.1 Seed bed preparation

Seedbed preparation for establishing forage cereals is the same as that required for high

yielding grain cereals. The main objective is to ensure that risks to good establishment are

minimised and that adequate plant numbers are achieved to ensure unlimited production

potential.

The choice of cultivation technique should take into account soil type, previous crop, presence

of weeds and crop residue, diseases, soil structure, moisture, compaction, equipment and

labour available and seasonal workload. Cultivation accelerates decomposition of soil organic

matter and destroys soil structure if overworked. This may lead to excessive loss of nutrients,

particularly N, during wet winter periods.

The best seedbeds are prepared by ploughing and subsequent surface cultivation; however,

minimum tillage and direct drilling potentially have large benefits for protecting soil structure

from excessive breakdown and nutrient loss. Insecticide (e.g. Lorsban®, Pirimor ®, Karate ®)

application with pre-cultivation herbicide is good practice to control chewing insects, e.g. grass

grub and Argentine stem weevil, especially if preparing paddocks out of old pasture.

On stony soils or on soils with high clay content, a single pass with a power harrow and

Cambridge roller following ploughing is sufficient. Barley is more sensitive to soil capping, which

can severely influence plant establishment, so requires a finer seedbed than triticale, wheat or

oats.

3.2 Sowing date

Autumn sowing

A yield gain is expected with earlier sowing in the autumn based on trends in FAR cultivar

performance trial results (FAR 2019a, 2019b). Seasonal differences may affect the potential

yield response as demonstrated in the 2013–14 trial in Lincoln comparing 12 April and 16 May

sowing (Arnaudin et al. 2015). Establishment conditions were not ideal for plots sown on 12

April 2013, with 179 mm of rainfall occurring from 12 April and the later sown 16 May plots.

Altering sowing date did not result in differences in silage harvest date. The benefits of early




sowing may only be realised if growth conditions are favourable for rapid establishment and

early growth.

Cereals germinate in soil temperatures above 4ºC, taking 25–35 days to emerge in mid-winter

and 7–15 days in autumn or spring. Early sowing, in irrigated light soils or dryland situations, is

recommended as soil moisture content is the factor that has the greatest impact on yield

potential. Autumn and winter-sown wheat and triticale usually have a higher potential yield than

spring-sown crops.

Spring sowing

Spring cultivars of triticale, barley, wheat and oats can be sown up to November. If sown later

than mid-October, barley cultivars give the best yield.

Delays in spring sowing can have an effect on potential yield, e.g. triticale sown on 15 August

compared with 30 September is expected to give a 1.5 tonne/ha increase in grain yield

(Table 2). Modelling and trial results with triticale show a 3 tonne/ha dry matter biomass (DM)

yield advantage, primarily because of more efficient use of soil water.

Barley is quicker from sowing to maturity than either wheat or triticale. Therefore, barley is a

better choice if sowing is delayed. November is considered ‘late’ in Canterbury and December is

‘late’ for Southland.

Table 2. Predicted effects of spring sowing date on triticale yield using a cereal growth

model (de Ruiter et al. 2012).

Sowing

date

Biomass at

flowering

(t/ha DM)

Grain fill

duration

(days)

Total yield at

maturity

(t/ha DM)

Grain yield at

maturity

(t/ha DM)

15 August 10.0 35 18 8.0

30 September 8.5 27 15 6.5

DM = dry matter.

3.3 Sowing rate

Recommended sowing rates may be different for individual cultivars depending on desired plant

populations, seed size and seed quality (final establishment rate). In general, established

populations of 250–300 plants/m2 for most cereals result in ‘close to optimum’ canopy

development. The following calculation for sowing rate adjusts for germination percentage,

expected establishment, and mean 1000 seed weight (TSW).

Sowing rate calculation (kg/ha) = (population x TSW(g) / (germination % x field

establishment %) x 100

e.g. Sowing rate = (300 x 50) / (95 x 90) x 100 = 175 kg/ha.

Typical sowing rates for oats, barley, wheat and triticale are given in Table 3. Rates should be

increased by 10% for direct drilled, late-sown or marginal conditions (wet, cold, birds, poor

cultivation) to ensure desirable populations are achieved.




Table 3. Typical sowing rates for respective species.

Species kg/ha

Barley 120–140

Wheat 120–150

Triticale 135–150

Oats 100–120

3.4 Sowing depth

Sowing depth should be 3–4 cm. Shallower depth, from broadcasting can lead to reduced

establishment due to bird damage, soil surface drying out or poorer root anchorage. Deep

sowing may reduce establishment especially if there is soil capping.

3.5 Seed treatment

Seed for most spring crops should be treated with fungicides (e.g. Raxil® or Baytan®) to reduce

seed-borne and seedling diseases. Insecticides (e.g. Poncho® or Gaucho®) can also be applied

to the seed to reduce grass grub or insect attack, especially in warmer environments, instead of

applying foliar insecticides after emergence.

4 Overview of current species options

Key points:

The choice of species is dictated by the fit with sowing date, the feed quality

requirement and the fit of the crop within the cropping rotation.

A strong factor in species selection is the total biomass yield potential. Relative grain

yield production within species is a useful indicator of the value of a cultivar for WCS.

Base cultivar selections on phenology (suitability for autumn or spring sowing), growth

duration, regrowth after grazing, tillering capacity, waterlogging tolerance, winter

hardiness, total herbage yield, grain yield, grain:stem ratio, disease resistance, lodging

resistance, height and response to straw shortener, resistance to grain shattering,

protein content, total soluble carbohydrate composition and ME.

The choice of species depends on the intended use in the farm system. Within these species

there are a range of cultivars available from seed suppliers with appropriate characteristics for

WCS production. Wheat, barley and oats have traditionally been used but triticale offers high

yield potential, good disease resistance and medium quality. Oats are used less often because

they have a lower grain to straw ratio and lower ME than other cereals. Oats offer flexible

options for mixing with legumes such as peas or vetches. Legumes can be mixed with any

cereal, usually giving a protein increase but a yield reduction. They need to be managed

carefully to ensure the right proportions are produced and weed control is adequate.




4.1 Traits for cultivar selection

Some cultivars have been specifically developed for forage use, but other cultivars are also

suitable for both silage and grain. Plant characteristics that can lead to profitable, high quality

silage crops include high grain yield, high grain:stem ratio, and good disease resistance.

Wheat, barley, triticale and oats can all be used for cereal silage. The choice of species will

depend on what is required for feed quality and how a particular sowing date fits with the

intended cropping rotation. Crop cultivars have differing yield potential and differing quality so it

important to choose cultivars that work well for the intended use and the timing of feed

requirement. For example, an earlier harvest creates an opportunity to sow another crop after

WCS and therefore an increase in the overall profitability of the crop system. Early work on

regional performance of WCS in the South Island concluded that triticale yielded better than

barley, which yielded more than wheat. (FAR 2002c). Barley had the best quality, then triticale

and wheat. Oats had relatively poor quality.

4.1.1 Barley

Barley is suitable for spring or winter sowing for whole-crop silage. It is less suited to a green

chop harvest because of relatively lower yields at that stage. It matures quicker than triticale or

wheat, so is preferred when sowing is delayed until mid to late spring. Spring-sown barley

develops more rapidly to maturity than either wheat or triticale, and therefore is more suited to

late sowing. October is considered late sowing in Canterbury, and December is ‘ate for

Southland. Barley is a good option if the aim is to follow with another crop. In a dryland

situation, an early harvest may be preferred when there is high risk of yield loss from drought in

later maturing crops. Barley is usually considered to have less tolerance to waterlogging,

particularly through the winter so wheat or triticale may be preferred in wetter areas in the winter

unless an early harvest is required. Autumn-sown barley may be susceptible to diseases such

as scald, which is less prevalent in spring-sown barley. Some new barley cultivars are high

yielding when autumn sown and are able to be harvested sooner than wheat or triticale. A

barley option for silage is useful for spreading harvest timing as harvest of later maturing

cultivars may coincide with harvest of ryegrass or grain crops.

Cultivars: Current best silage types include: ‘Bumpa’, ‘Cask’, ‘County’, ‘Dash’, ’Doyen’,

‘Monty’, ‘Retriever’, ‘Sanette’, ‘Tavern’ and ‘Vortex’. The ranking among

cultivars will change with time depending on disease tolerance.

Others: ‘Booma’, ‘Gangway’ (CRBA148), ‘Fortitude’, ‘Liberator’, ‘Ruapuna’

An annual review of options should be considered in consultation with market

availability. Refer to FAR (2019a and 2019b) for more cultivars.

4.1.2 Wheat

Wheat can be sown in spring, autumn or winter. Wheat normally requires high fertility and good

moisture levels, so it should be sown in paddocks known to be more productive. Autumn sown

wheat is usually tolerant to waterlogging and has the capacity to extract moisture and nutrients

from depth to 1.5 m. Cultivars differ in maturity so it is important to select varieties to suit the

proposed time of harvest.




Cultivars: Autumn sown: ‘Conquest’, ‘Discovery’, ‘Duchess’, ‘Empress’, ‘Excede', ‘Raffles’,

‘Reliance’, ‘Ruapuna’, ‘Saracen’, ‘Tribute’, ‘Torch’, ‘Viceroy’, ‘Wakanui’.

Spring sown: ‘Conquest’, ‘Discovery’, ‘Raffles’, ‘Reliance’, ‘Sensas’, ‘Viceroy’.

Refer to FAR (2019a and 2019b) for more information on suitability. Many of

the cultivars bred for milling quality may also have characteristics suitable for

silage production.

4.1.3 Oats

Oats are usually grown for forage or green chop silage rather than for whole crop silage as it is

difficult to adequately compress in a silage stack at the later direct chop stage. Mature oats also

have a low harvest index and the overall quality of silage is lower than other species. Forage

oats are highly productive (total feed value produced on an area basis) at the time of a green

chop harvest. Early autumn-sown crops produce high biomass yield for winter single graze, but

do not usually regrow for subsequent grazing. If sown in mixtures with Italian ryegrass in

autumn, the crop can be sequentially grazed. Oats can be sown in February for early-winter

grazing, through to April–May in milder climates. If carrying oats through the winter, the quality

will decline sharply, especially if stem elongation occurs, as it is prone to frost damage and

lodging.

In the North Island, oats are popular following maize crops and used for green chop silage in

September. Oats yield up to 44% higher than annual ryegrass in Taranaki and Waikato (FAR

2013b). Lodging is often more prevalent in oats than other cereals. Oats can also be sown in

early spring to produce green-chop silage. This is an effective way to ensure adequate silage

storage in districts where dry spring weather often restricts amounts of grass silage that can be

harvested. The cultivar ‘Milton’ is a recent selection out of US germplasm with increased

disease resistance and rapid growth. ‘Coronet’ was bred to replace Hokonui and is a later

maturing cultivar that can be sown in autumn or spring. It has improved disease resistance and

high leaf to stem ratio suitable primarily for green chop and less so for WCS.

Cultivars: ‘Armstrong’, ‘Coronet’, ‘Hattrick’, ‘Hokonui’, ‘Intimidator’, ‘Magnum’, ‘Makuru’,

‘Milton’.

4.1.4 Triticale

Triticale is a cross between wheat and ryecorn. Most autumn-sown triticale cultivars can only be

grazed once, but cultivars like ‘Doubletake’ will regrow after grazing, then kept for summer

silage production. Triticale is also sown in winter and early-spring for whole crop silage

production, with no grazing. Triticale usually has better disease resistance than wheat and is

tolerant to take-all disease, Triticale can be a better option if considering a second or third

wheat crop if take-all inoculum is present. The crop has a potential to produce high biomass

yield, but the quality is low because of high stem fraction and low grain:stem ratio. The cultivar

‘Prophet’ was bred for high tiller density and larger head size, and with good disease resistance,

winter hardiness and grazing tolerance has desirable attributes for characteristics for green

chop silage and WCS.

Cultivars: ‘Bolt’, ‘Crackerjack’, ‘Doubletake’, ‘Prophet’.




4.2 Cultivar selection, silage yield and crop duration

Results of cultivar performance trials (CPT) in previous seasons provide a reference point for

selecting potential silage cultivars (FAR 2019a, 2018b). This covers the range of wheat and

barley cultivars currently in use for grain production. Selections with high relative grain yield also

have high total forage biomass yield. This is based on a relatively conservative harvest index

(HI) plant trait at least within species. Also, cultivars with high grain yield are also likely to have

elevated ME because of the high starch fraction in the grain.

FAR trials sown in the autumn of the 2013 and 2014 harvest seasons in Lincoln showed

differences between cereal species and cultivars (Table 4). In 2013–14, triticale produced the

highest yield at 25.5 t/ha followed by wheat (22.6 t/ha) and barley (15.6 t/ha) (Arnaudin et al.

2015). There were yield differences (p<0.001) between trial entries in 2013–14, but not in 2014–

15. In 2013–14, the later maturing ‘Wakanui’ wheat yielded 3.6 t/ha more than the earlier

maturing ‘Morph’ wheat. Similarly, in barley, the later maturing ‘Retriever’ and the six-row

cultivar (205-14) produced higher yields than the early maturing ‘Tavern’.

Table 4. Crop yields (t/ha) for common silage entries in the 2013–14 season (A) and 2014-15 season

(B) autumn-sown cereals in Lincoln, Canterbury. In B, mean yield was at silage harvest (38% dry

matter (DM)) and growth rate between flag ligule (GS39) and ears fully emerged (GS86).

Species Cultivar

Yield (t DM/ha)

Green chop harvest

Sowing date

12 April 16 May

A: 2013–14, Autumn (averaged over N rate)

Barley mean

-- 15.2 16.0

‘205-14’ -- 18.1 16.9

‘Tavern' -- 10.4 12.5

‘Retriever’ -- 16.8 16.4

Triticale ‘Prophet’ -- 28.4 25.5

Wheat mean

-- 22.6 22.7

‘Morph’ -- 20.1 21.5

‘Wakanui’ -- 25.1 23.9

B: 2014–15, Autumn (averaged over PGR treatments)

7-May sowing Growth rate (GS39

to GS86) kg DM/ha/day

Oats ‘Coronet’ 4.9 19.6 263.8

Barley ‘Sanette’ 3.1 19.9 259.4

Triticale ‘Prophet’ 4.5 23.2 342.3

Wheat mean

4.3 21.4 319.7

‘09-25’ 3.9 20.0 274.7

‘12-45’ 4.4 22.1 328.9

‘Raffles’ 4.5 21.6 302.4

‘Torch’ 4.2 22.3 335.6

‘Wakanui’ 4.8 20.8 357.1




In the 2014–15 trial, triticale and wheat again had higher yield than barley, with significant

differences (p<0.033) between the species (Table 5). No yield differences were observed within

wheat cultivars in 2014–15 despite having been chosen for a range of maturities. However,

there were differences (p=0.006) in the rate of growth during the period GS39–GS86. The later

maturing cultivars (‘Wakanui’, ‘Torch’ and ‘12-45’) had higher mean daily dry matter change

over that period compared with the earlier maturing ‘Raffles’, ‘Morph’ and ‘09-25’, (Arnaudin et

al. 2015) (Figure 1).

Figure 1. Maturity differences between wheat cultivars (‘Morph’ and ‘Wakanui’) sown on 12 April

2014.

4.3 Growth stages

An international decimal system (Zadoks et al. 1974) is used to describe the visible stages of

plant growth from emergence to maturity (Table 5. Many management recommendations refer

to specific growth stages for timing of management operations (FAR 2015).

Cereals can be planted over a wide range of dates and temperatures. Sowing dates for autumn

and spring cereals are discussed in Section 3.1.2. Plant development is governed by

temperature and daylength, so it is more accurate to manage the crop based on growth stages

rather than calendar time, or days from emergence.




Table 5. Decimal growth stages for cereal crops (Zadok et al. 1974)

Code Description Code Description

Seedling growth Ear emergence

10 First leaf through coleoptile 51 First spikelet of ear just visible

11 First leaf unfolded 55 Half of ear emerged

13 3 leaves unfolded 59 Ear completely emerged

15 5 leaves unfolded Flowering

Tillering 61 Start of flowering

20 Main shoot only 65 Flowering half way

21 Main shoot and 1 tiller 69 Flowering complete (all pollen shed)

23 Main shoot and 3 tillers Milk development

25 Main shoot and 5 tillers 71 Grain watery ripe

Stem elongation 73 Early milk

30 Ear at 1 cm 75 Medium milk

31 First node detectable 77 Late milk

32 Second node detectable Dough development

37 Flag leaf just visible 83 Early dough

39 Flag leaf blade fully visible 85 Soft dough

Booting 86 Cheesy dough

41 Flag leaf sheath extending 87 Hard dough

43 Flag leaf sheath visibly swollen Ripening

45 Flag leaf sheath swollen 91 Grain hard

47 Flag leaf sheath opening 92 Grain hard (not dented by thumb nail)

49 Awns emerging 93 Grain loosening in daytime




5 Nutrient management

Key points:

Two applications of N fertiliser are recommended. Autumn-sown crops usually do not

require N at sowing but is recommended for spring sowing. The second timing event is

at GS2.3 – GS3.1 to promote tillering and stem elongation. A late application may be

required at GS39 flag ligule depending on the crop N demand.

Two applications of N will be sufficient regardless of timing, with a maximum of 120 kg

N/ha of fertiliser or 250 kg N/ha in the available N pool (soil N + fertiliser N).

N management should aim to alleviate any N stress during the tillering and stem

elongation phase, and also strategically to maintain healthy green leaf tissue until the

projected silage harvest. Green leaf and stem at harvest is important for supplying a

fermentable carbohydrate pool to assist the ensiling process. An ideal visual green leaf

content is shown in Figure 2 (right).

Apply a basal P application at sowing of up to 36 kg/ha if the Olsen P is <20 µg/mL

determined in pre-sowing test, or 15–20 kg/ha if the Olsen P is >20 µg/mL.

Apply 50 kg K/ha as a starter K fertiliser, and allow for 50 kg K/ha as a part offset for K

removed in WCS.

Basal applications of S (15–25 kg S/ha) and Mg (20–30 kg Mg/ha) fertiliser will account

for N removal in WCS crops.

5.1 Overview of nutrient management

The principles of N management in feed wheat and barley grain crops are covered in FAR

(2013a) ‘Cropping Strategies’ and generally apply to all cereal silage crops. Principles for

optimising yield in a wheat crop and equally applicable to barley and triticale crops are:

15 kg N fertiliser is required per tonne of DM produced. N required is calculated as

additive soil N plus fertiliser N. In dryland wheat, the N use efficiency is lower at 19 kg N

per tonne of DM.

The timing of application can be the same as grain crops with 2/3 of the N applied at

GS32 and 1/3 at GS3. In spring-sown crops, and in cases where early soil N levels are

low, application of N at GS25 to GS30 is likely to increase crop yield.

A 10 t/ha crop contains 150 kg N/ha (15 kg N/t DM). Applied fertiliser N is used at

approximately 80% efficiency in wet or irrigated conditions and approximately 60% in

dry land conditions.

Alluvial and sedimentary soils of moderate fertility require approximately 150 kg N/ha, 36 kg/ha

P, 50 kg/ha K, 20 kg/ha S and 15 kg/ha Mg. Calcium is generally not required if pH is greater

than 5.5. A well-managed crop will take up 300 kg N/ha, so approximately half of the N is from

fertiliser and half from soil reserves.

Fertiliser applications should be planned so that optimum levels of nutrients are available for

expected crop yield and quality. Soil sampling before sowing will help with decisions on levels of

nutrients to apply (Table 6). Fertiliser use increases the yield potential and can also change the

nutrient profile in the crop.




Typically, 200–250 kg/ha of Cropmaster 15, Cropmaster 20, Cropzeal 16 or Diammonium

phosphate (DAP) are applied at sowing. Most triticale, wheat and oat crops will also benefit from

50 kg N/ha (100 kg/ha urea) broadcast and incorporated prior to the last cultivation or applied

soon after emergence, increased to 75 kg N/ha in direct drilled, irrigated light soil, late sown or

‘turf still breaking down’ situations. Barley crops, being faster developing, will typically respond

to 75–100 kg N/ha in the above situations.

Table 6. Indicative fertiliser requirements for given soil tests (MAF Quick test units).

Phosphorus Potassium Sulphur

MAF Q test

Fertiliser requirement

(kg/ha) QTK


(kg/ha) QTS


(kg/ha)

0–10 20–30 0–2 30 0–2 30

11–19 15–20 3 10 3–4 20

20+ nil 4+ nil 6+ nil

Currently accepted practices for nutrient management of cereals are summarised in the industry

guide ‘Managing soil fertility on cropping farms’ NZFMRA (2009). Fertiliser requirements need

to be given within the context of the soil parent material and their drainage capacity. Free

draining sedimentary soils (yellow grey earths, yellow brown earths and recent alluvial soils)

have differing nutrient availability patterns to imperfectly drained sedimentary and peaty soil

types. Soil organic matter levels can decline quickly with successive annual cropping from 3–

5% when first cultivated from pasture. The free draining sedimentary soils have low K reserves

(low TBK) compared with imperfectly drained soils with medium to high K reserves. Allophanic

(volcanic ash soils) are also generally suitable for cropping but have low K reserves.

5.1 Fertiliser requirements

5.1.1 Nitrogen

Nitrogen (N) fertiliser is a major expense but adequate N is essential to ensure good crop yield

and protein concentration. However, over fertilising with N can have negative effects on the

environment through excess volatilisation, immobilisation, denitrification and leaching, as well

as compromising profitability for the farmer. Most of the fertiliser used is in the readily

hydrolysable form of urea. Alternative forms of controlled and slow release N fertilisers have

been shown in a number of studies to regulate the timing of N release to match the N uptake

pattern and therefore improve the efficiency of N use (Grant et al. 2012, 2016; Malhi et al.

2010). However, if the intention is to produce wheat crops with high concentrations of

harvestable protein, the application of fertiliser with quick release of N for uptake would be most

desirable but not necessarily best for the environment, as there is a high possibility of residual

N loading following crop harvest. However, cereal crops do have a high capacity to remove

available N from soil and accumulate the N in tissues.

The efficiency of N use can be defined under criteria such as productivity relative to the uptake

of N, productivity relative to the amount of N applied or productivity relative to the total soil

N available to the crop. Key indicators of efficiency are harvest index (HI) defined as grain

biomass/total biomass, and N harvest index (NHI) (fractions of N in grain relative to total

N uptake). Yield and N accumulation in the plant is driven not only by environmental and




management factors, but also by plant genetic factors (van Sanford and MacKown 1986, which

may reduce the responsiveness of the crop to differing N inputs. Differing efficiency is likely to

be related to the capacity of crops to concentrate N in the plant parts (leaves, stems, grain and

chaff), and the yield of the component parts.

Recommendations are to apply 100–120 kg N/ha for spring-sown triticale, wheat and oat crops

and 50 kg N/ha for barley at mid- to late-tillering (GS23-30). In very high yield or visibly low

N stress situations, a further increase in yield can be achieved by applying another 50 kg N/ha

at booting (GS41 to GS49).

The optimum number of mature tillers will vary depending on the sowing date and crop species,

e.g. 450–500 per m2 for spring wheat and triticale and 800–900 per m2 for spring barley. For

winter-sown crops, an ideal tiller population at flowering is 550–600 per m2. Usually, 15–20%

more tillers are produced than will survive to maturity. N applications after tillering may increase

whole crop N status and reduce the decline in N concentration of grains as they mature. There

is usually little yield increase from application of N fertiliser after awn tip emergence (GS49).

Recommendations for N application use are based around the timing of growth and

consequently the net demand for nutrients. N is used strategically to develop and support the

final tiller number target with an emphasis on maximising the leaf size of the upper half of the

plant, reducing straw and enhancing grain production to produce good yield and quality. The

peak demand for N occurs as the stem is elongating (GS30–39). Application of excess N before

mid-tillering (GS20–23) will result in too many tillers. Typical patterns of N uptake show a lag

phase up to GS30, a fast period of uptake up to flowering (GS60), and then a slower phase

during grain filling and maturation. Approximately one-third of the N should be applied at sowing

to support initial tiller development, followed by a second split at GS 30–31 (first node) to build

stem and leaf reserves. Late application of N in grain crops is recommended at flag leaf

emergence (GS39) to boost yield. The late N application may also be appropriate for silage

crops to increase the protein content and promote a higher green leaf fraction (higher green leaf

area and extended leaf area duration) of the standing crop at the time of cutting for silage.

An added benefit is a higher concentration of fermentable carbohydrate to assist the ensiling

process.

In Lincoln (2012–13), spring barley (‘Monty’) trial (de Ruiter and Maley 2013), N fertiliser

consistently increased yields in irrigated and dryland treatments. Increasing the N rate from

50 to 100 kg N/ha raised yield by 1.8 t/ha in the irrigated trial, and this was increased by another

1.4 t/ha when 200 kg N/ha was applied, along with a delay in stover maturation (Figure 2).

A similar response occurred in the dryland trial, but with a slightly lower yield gain 1.5 t/ha for

the 50 kg N/ha to 100 kg N/ha and no further increase for the high fertiliser rate. The capacity of

crops to respond to time rate of N fertiliser is dependent on the amount of early season

N uptake, weather conditions and soil moisture status.

In an autumn-sown trial (2013–2014), there was an interaction between sowing date and N rate.

Plots sown on 12 April benefited from having 250 kg N/ha compared with 150 kg N/ha applied

while plots sown on 16 May did not. Using the mean for all cultivars (‘205-14’, ‘Tavern’,

‘Retriever’, ‘Prophet’, ‘Morph’ and ‘Wakanui’), the earlier sown plots yielded 20.1 t/ha when

250 kg N/ha was applied and 17.8 t/ha for the 150 kg N/ha treatment. N application had only a

minor influence on the development rate. Crop development is faster in later sown crops, so the

timing of N applications can be more critical for stimulating tillering and setting the crop up for a

high yield.




Figure 2. The effect of

N rate on green leaf area

retention for irrigated

‘Monty’ at the same stage

of grain development.

General N recommendations for different fertility situations are given in Table 7. This will differ

for the expected yield. An example is given for 15 and 20 t/ha biomass of WCS. Excessive N

use may have detrimental environmental effects, e.g. leaching of mineral N into ground water.

Most of the N applied as fertiliser will be taken up by the crop and the remainder of the crop

requirement will be derived from the soil mineral pool. The available N pool (soil plus fertiliser-

derived N) should not exceed 250 kg/ha. Additional information for managing N and minerals in

silage crops is given the publication by NZFMRA (2009).

Table 7. Recommended total amounts of N fertiliser (kg N/ha) for differing soil fertility and

expected yield for whole-crop cereal silage. Potentially available N (PAN) is determined

from anaerobically mineralisable N (AMN test) and adjusted for 0–30 cm depth.

No. of years since pasture

N Source 0 1 2 3–4

PAN (kg N/ha) 200 150 150 100

Fertiliser N requirement

N requirement (kg/ha) for 15 t/ha yield 50 75 125 150

N requirement (kg/ha) for 20 t/ha yield 150 175 225 250

5.1.2 Phosphorus

Canterbury soils typically have a low capacity for P release by mineralisation. Application of

P as a base dressing at sowing is generally recommended. Apply 15–20 kg P/ha if Olsen P is

higher than 20 µg/mL and apply 36 kg P/ha if Olsen P is less than 20 µg/mL.

Typical herbage content of P in spring-sown crops is between 0.10–0.25%. Phosphorus

removal in the harvested crop may exceed 36 kg/ha.




5.1.3 Potassium

Most Canterbury soils have very large K reserves that are slowly mineralised over time.

Sedimentary soils with marginal QTK can be test for reserve K (TBK test) to determine

availability of reserve K. If TBK <1.0 then K fertiliser should be applied at a basal level of

50 K/ha is sufficient to ensure non-limiting yield. During periods of rapid plant growth or during

dry periods, release of soil potassium may be lower than crop requirements. WCS takes up

250–300 kg K/ha and much of this is derived from exchangeable or mineralised K.

Approximately 200 kg/ha of K is removed in silage harvest and much of this is in the straw

fraction. Around 20–30% (approximately 50 kg K/ha) of the potassium removed at harvest

should be reapplied during establishment of a following crop.

5.1.4 Sulphur

The total requirement for S is 15–25 kg S/ha, but sulphate is especially prone to leaching so

addition of S may be required in spring if an autumn-sown crop has gone through a wet winter.

If the sulphate test is >6, no S fertiliser is required, if the sulphate test is <6, apply 20 kg S/ha.

Up to 30 kg/ha is removed in a silage crop.

5.1.5 Magnesium

Magnesium deficiency is rare in cereal crops. Base applications of 20–30 kg Mg/ha are

recommended to offset removal of up to 20 kg/ha Mg in a silage crop. There is a trend for

declining Mg in cropped soils. Good magnesium content is essential for animal health.

Magnesium fertilisers are required if cropped areas are regrassed.

5.2 Nutrient removal

There is significantly more nutrient removal with crops harvested for silage than for grain. Up to

250 kg N/ha and 300 kg K/ha are potentially removed in forage harvests along with smaller

amounts (<50 kg/ha) of other nutrients (P, S, Ca and Mg) (Table 8). Local differences in soil

nutrient concentration and differences between cultivars in their potential for uptake can explain

the differences in nutrient amounts taken up by the crops.

High relative concentrations of N, P, S and Mg occur in grain, whereas K, Ca and Na

concentrations are low in the grain fraction.

Table 8. Range of nutrient removal (kg/ha) in whole crop silage and supply of nutrients from

soil for a 15 t/ha crop of cereal, and 24 t/ha of maize for comparison.

Cereal silage Maize silage

Removed by crop

(kg/ha) Supplied by soil

(kg/ha) Removed by crop

(kg/ha)

Nitrogen 200–250 75–150 230

Phosphorus 15–50 15–50 48

Potassium 150–300 80–250 144

Calcium 20–50 – –

Sulphur 13–22 10–20 14

Magnesium 10–15 – 38




6 Weed control

Key points:

There are effective chemical control options for ryegrass in cereal crops; however, there

is a case for allowing grass species to survive under a cereal crop to enhance the

quality, although this is more difficult to manage for longer duration crops.

Use broadleaf chemical weed control as for cereal grain crops, but be aware of any

holding periods if weeds are sprayed after GS39.

Cereal crops for WCS should be sprayed at the appropriate time for control of broadleaf weeds

as per a grain crop. Options for broadleaf weed control are not given here as there is a wide

selection of chemical with different specificity for target weeds. Consult chemical manuals,

distributors or representatives for the appropriate herbicides to control the weeds identified, and

conform to any withholding periods specified for the chemicals.

Cultivated pastures can contain seeds of many broadleaf weeds (docks, willow weed, redshank,

dandelions, buttercup) that can compete strongly with establishing cereal crops. If left

unchecked they will reduce yield, quality and animal acceptance/palatability. If weeds are killed

or checked sufficiently with an herbicide, the rapidly closing crop canopy will usually suppress

further weed development.

It can be advantageous to include ryegrass as part of the cereal silage crop to improve the crop

protein composition; however, it is difficult to predict what influence a ryegrass component may

have on the growth of the cereal. An advantage of establishing ryegrass with a cereal is that the

ryegrass will continue to grow after the main cereal has been harvested. Barley crops with a

short duration to silage harvest are usually more successful as a crop mixture as it tends to be

shorter and allow more light to penetrate the canopy.

A New Zealand study (Rolston et al. 2003) has shown there are a number of control options for

grass weeds in wheat and barley, in particular pre-emergence mixtures of cyanazine +

terbuthylazine; chlorsulfuron + terbuthylazine; or metribuzin. Good control of phalaris, perennial

ryegrass, Italian ryegrass, prairie grass was achieved, but brome was difficult to control. There

are a number of chemical products that can selectively take out ryegrass.

7 Insect control

Emerging seedlings can be attacked by Argentine stem weevil and also by aphids

carrying barley yellow dwarf virus (BYDV), both causing irreversible damage in adult

plants. Other insects (cutworm or aphids) can cause leaf or ear damage in adult plants

and should be monitored during the season and decisions made to combine an

insecticide when applying other products such as fungicides.

An insecticide (e.g. Karate) should be used at GS 12 (2 leaf stage) and again 17–21

days later to control insect damage, especially in warmer climates.




8 Disease management

Key points:

Follow principles of disease control developed for cereal grain crops.

Management of fungicide timing is important with regard to withholding period as leaf

and stem diseases often appear at critical late-timing coinciding with the latest

permissible application (Table 9).

Multi-site application is recommended to reduce the development of resistance.

Succinate dehydrogenase inhibitor (SDHI) fungicides are also prone to resistance

development. Mixes of triazole and strobilurin give the best control and protection to

maintain maximum green leaf area and enhancing the fermentation characteristics.

Important barley diseases are: ramularia, powdery mildew, net blotch, scald.

Important wheat diseases are: septoria, fusarium, stripe rust, leaf rust, tan spot,

powdery mildew. Integrated disease management approaches with specific rates and

timing involving triazoles, SDHI and strobilurin fungicides have proven to be effective.

In general, triticale crops require less fungicide than other cereal crops, but are

susceptible to fusarium in humid weather.

8.1 Overview

Soil diseases can be difficult to control, especially where cereal crops have been grown

frequently and there is carry over in crop residue or on alternative host plants. Wheat is much

more susceptible to take-all, crown and root rot than triticale or barley. Prevention and control of

leaf diseases can be effective through monitoring of disease symptoms and by timely chemical

application for the target disease such as mildew, net and spot blotch, scald, Ramularia, and

leaf rust in barley and stripe or leaf rust in wheat or triticale.

In many situations the most important fungicide application time occurs around full emergence

of the last leaf (GS39). All medium to high yielding crops should receive one fungicide, at full or

close to full rates, to prevent late-season fungal infection. This is the last chance to protect the

crop during the critical grain filling and harvesting period, helping to produce the highest

possible yield and quality.

Mixes of both a triazole and strobilurin fungicide give the best control and protection. Some

products are available ready mixed. Strobilurin fungicides have a secondary effect of increasing

green leaf retention by 3–6 days. Maintaining the green leaf area for longer into the grain filling

period has the benefit of producing more soluble sugars and starch.

Diseases in cereals can markedly reduce the yield by reducing the green leaf area and thereby

reducing radiation interception, by reducing the root development and by causing plants to

lodge. The principles of disease management in cereal silage are generally similar to growing a

cereal grain crop. For more detail see (1) FAR (2015) ‘Cereal growth stage guide’ and (2) FAR

(2018) ‘Cereal disease management’. Effects of disease incidence on yield of cereal silage may

not be apparent in spring crops or where disease pressure is low. Maintenance of clean green

leaf area in silage crops is important as the soluble carbohydrate content in green leaf and

green stems have an important function in providing readily fermentable sugars for the ensiling

process.




Species and cultivars differ in susceptibility to both foliar and root diseases, so a first good

management practice option is to select species or cultivars with resistance to key diseases. In

addition, there are a range of cultural methods, such as crop rotation, stubble management and

time of sowing that can be used to minimise disease in cereals.

Use of fungicides for disease management follows the same principles as for grain crops.

However, the timing of application is important as particular fungicides must not be used on

crops to be fed to animals (e.g. Chlorothalonil) and the withholding period may differ between

grain and silage crops. In general, triticale crops require less disease control interventions than

other cereal crops. However, in humid environments, fusarium is problematic in triticale and

wheat, with reduction in grain size and possibly elevated mycotoxin levels. Fungicide control of

Fusarium is not usually successful.

In the 2012–13 season, the influence of a single fungicide application (strobilurin + triazole

applied at GS49) on silage yield and quality was investigated for a new spring-sown awnless

barley cultivar (‘Monty’) in Canterbury and Southland. The irrigated trial at Lincoln showed an

effect of fungicide on specific leaf area, the ratio of leaf:total dry weight, and leaf area index.

Leaf area index was also increased in the dryland trial with fungicide application. While

fungicide extended the duration of green leaf area, there was no significant effect on silage yield

in the Lincoln trials. However, fungicide had a strong effect on final grain yield in the irrigated

trial with an average increase of 1.41 t DM/ha compared with the control treatment. Grain size

was increased by 3.5 mg/grain in fungicide treated plots. Enhanced leaf area duration was

proposed as a mechanism for the higher yield potential.

In 2013–14, fungicide effects were also assessed in a non-irrigated trial in Woodlands,

Southland, where a mixture of Triazole + SDHI (succinate dehydrogenase inhibitor) at GS57

was compared with nil fungicide. As for the Lincoln dryland trial, there was no yield response to

fungicide treatment. However, fungicide did lower the %DM and slowed the rate of crop dry

down. The difficulty of a late (GS57) fungicide application is the withholding period which is at

the margins for safe silage harvest. In other species, and especially for early-sown barley, the

effect of fungicide on yield may be more apparent as the crops are exposed to higher disease

pressure.

8.2 Disease control including timing and efficacy of

fungicides in cereals

All of the disease control practices for cereal grain production are relevant to WCS production.

The latest comprehensive guide for cereal disease management is documented in FAR (2018).

This covers key timings and management strategies for autumn sown barley, spring sown

barley and autumn sown wheat.

There are three modes of action for common fungicides for cereal disease control:

a. Strobilurins, e.g. Amistar, are at the highest risk of pathogen resistance development.

Septoria triticii blotch (STB) in wheat and ramularia and powdery mildew in barley are

already resistant to strobilurins in New Zealand, so strobilurin fungicides will be

ineffective on these diseases.




b. Triazoles are at low-moderate risk of pathogen resistance development. Resistance to

the triazoles develops slowly over a number of years with multiple mutations. The

Zymoseptoria pathogen is showing a shift in sensitivity to triazoles e.g. epoxiconazole

(Opus) in New Zealand.

c. SDHI fungicides e.g. Aviator Xpro, are at moderate-high risk of resistance

development. So far in New Zealand Ramularia is less sensitive to these products. In

Europe, Ramularia, net blotch and Zymoseptoria pathogens are developing resistance

to the SDHIs. SDHI fungicides need to be mixed with an un-related fungicide as an

anti-resistance strategy, since these products have a moderate to high risk of

resistance development (FAR 2010).

Not all pathogens present the same risk of developing resistance mutations to fungicide groups.

For example, the mutation that renders the STB pathogen resistant to strobilurins is lethal to

cereal rust pathogens, meaning that strobilurins such as Amistar and Comet are still very

effective against rust pathogens (FAR 2018).

Key principles are as follows:

Wheat diseases

Overall, FAR trial work still shows the more effective triazoles have reasonable activity

(75–90% control) against STB for example, but prothioconazole is superior to

epoxiconazole.

STB is a developing problem but fungicide programmes are successful in managing the

disease. Disease spread is driven by wet weather and long durations of relative

humidity >85%. There is large seasonal variation as demonstrated in Figure 3.

The economics of fungicide use for wheat cultivars with increased resistance to STB is

dependent on the prevailing weather conditions, e.g. a resistant cultivar will have less

yield loss than a more susceptible cultivar if weather delays spraying.

An integrated disease management (IDM) approach is documented for winter wheat.

Recommendations for timing, products and rates for triazole (epoxiconazole e.g. Opus)

and prothioconazole e.g. Proline) and SHDI application as triazole alone (Figure 8) or

combined triazole + SDHI applications (FAR 2018).

Triazole alone rate responses showed a linear decline with concentration (ranging from

25% to 100 % dose rate).

Triazole (75% rate) in combination with SDHI fungicides (Adexar and Aviator Xpro)

showed increased efficacy at the partial rates of SDHI. The optimum dose rate in terms

of yield response and margin was a 75% dose of SDHI (Adexar) mixed with a 75% rate

triazole (FAR 2018).




Figure 3. Progress of Opus and Proline treatment at GS31 and GS39 against

Septoria triticii blotch (STB) with assessment at GS 75–GS86 in Otago and

Canterbury (FAR 2018). The chemicals used in this trial were not mixed with

succinate dehydrogenase inhibitor (SDHI) fungicides.

Identification and pathological information for diseases such as septoria leaf blotch,

stripe rust, leaf rust, tan spot, powdery mildew, fusarium ear blight, and sooty mould are

given in commercial booklets e.g. ‘The Essential Fungicide Disease Planner’ (Bayer

Crop Science), with recommended control measures in ‘Cereal Disease Pocket Guide’

(Bayer Crop Science) and ‘Agronomy Challenges and Solution for Cereals’ (Syngenta).

Barley diseases

Ramularia (Ramularia collo-cygni) has been the main disease present in recent FAR

autumn-sown barley trials.

Ramularia together with leaf rust have been the main diseases present in recent FAR

spring sown trials.

Ramularia is resistant to the strobilurins and has recently become less sensitive to the

SDHI fungicides.

The new multisite fungicide Phoenix® has shown good control of Ramularia when used

in a mix with Proline, but yet to have registration for Ramularia.

Scald (Rhynchosporium) build up over winter is a problem for winter barley.

Seed treatment with Systeva (SDHI fungicide fluxapyroxad) is a suitable control option.

A maximum of two SDHI fungicides are allowed per season (including seed treatment),

to reduce the development of resistance.

Typical applications at T1 (GS30–GS31) are:

Proline 0.4 L/ha + Acanto 0.25 L/ha + Phoenix 1.5 L/ha

Proline 0.4 L/ha + Seguris Flexi 0.3 L/ha + Phoenix 1.5 L/ha

Aviator Xpro 0.5–0.7 L/ha + Phoenix 1.5 L/ha

Adexar 0.63–1.0 L/ha + Phoenix 1.5 L/ha




Adjustments are required if rust is present, as Proline + Pheonix has less efficacy against rust.

Also topping up the Triazole component for pre-mix multisite fungicides is an option when

disease pressure is high.

Typical applications at T2 (GS39–GS49) are:

Proline 0.4 L/ha + Acanto 0.25 L/ha + Phoenix 1.5 L/ha

Proline 0.4 L/ha + Seguris Flexi 0.3 L/ha + Phoenix 1.5 L/ha



The latest timing for this spray is GS39. At GS39 consider using Proline for Ramularia

and Phoenix for scald control.

Proline 0.4 L/ha + Phoenix 1.5 L/ha

Proline 0.4 L/ha + Seguris Flexi 0.3–0.6 L/ha + Phoenix 1.5 L/ha



Applications at T3 (GS59) may be required if T2 spray is early (GS39) and high rust

pressure.

Proline 0.2 L/ha + Seguris Flexi 0.3 L/ha

Proline 0.2 L/ha + Acanto 0.25 L/ha (if two SDHI fungicides have been applied

earlier).

A key point for disease control in spring barley is that yield gains of between 4 and 11% occur

with plant protection (FAR 2003, FAR 2018). Major diseases of barley include scald

(Rhyncosporium), net blotch (Pyrenophora teres), leaf rust (Puccinia hordeii), powdery mildew

(Blumeria graminis) and Ramularia. Results of field trials examining single and double spray

options, timing of application and chemical types show that yield gains can be achieved by

tayloring the management options for optimum efficacy. New chemical development, new

cultivar releases with differing resistance characteristics and development of chemical

resistance by the microbes, means a constantly changing platform for disease management.

The principles developed in historical studies still apply for control of specific diseases. As an

example, two sprays rather than a single spray at awn tip appearance (GS49) gave best control

of scald and net blotch with the most effective active ingredient being carbendazim (Protek),

strobilurin kresoxim methyl with Opus (Allegro®) or Twist. The strobilurins (Amistar and Comet)

were not as effective against scald but gave the best results against net blotch. Protek gave

poor results against net blotch.

There are known differences in disease pressure between spring vs autumn sowing with

interactions between duration of crop at particular growth stages, weather conditions and plant

susceptibility to disease.




8.3 Fungicide withholding periods for WCS

Withholding periods for fungicides range from 28 to 50 days. As a general rule, all spraying

should be completed before ear emergence (GS50). Farmers need to be careful to ensure the

withholding period for the product they are using fits the intended harvest time. With standard

crop management, there should be little risk of harvesting wsithin the withholding periods listed

for autumn-sown crops. Although, harvesting at the early end of the harvest window could put

some crops at risk of getting close to the allowable withholding period at harvest having applied

the chemical at GS39–GS49. It is important to keep a record of application dates to calculate

safe harvest times. Spring-sown crops will generally have a shorter window from GS39 to

harvest, so extra care should be taken to ensure a safe harvest.

Fungicides applied to WCS must conform to the withholding period defined by time from

application to crop harvest, animal re-entry into a paddock, or the time of forage consumption by

the animal as shown on labels for products. Common fungicides applied to cereals are listed in

Table 9. Further information for withholding protocols of chemicals used on cereal silage crops

are given in FAR (2016b).

Table 9. Withholding periods for common fungicide a use in cereal silage production (FAR 2016b).

Chemical group

Trade name Active ingredient Withholding period

Triazole

Alto® Cyproconazole 30 days

Opus® Epoxiconazole Harvest for grain – 21 days Cut for forage – 28–35 days

Tilt® Propiconazole Cut for forage – 30 days

Proline® Prothioconazole Harvest for grain – 14 days Cut for forage – 35–42 days

Folicure® Tebuconazole Harvest for grain – 30 days

Cut for forage – 28 days

Cereous® Triadimenol Harvest for grain – 30 days

Strobilurin

Amistar® Azoxystrobin Harvest for grain – 35 days


Comet® Pyraclostrobin Cut for forage – 35 days

Twist® Trifloxystrobin Cut for forage – 35 days

Acanto® Pixoxystrobin Cut for forage – 28 days

SDHI b Seguris Flexi® Isopyrazam Harvest for grain – 14 days


Other Protek® Carbendazim Cut for forage – 14 days

Before direct grazing – 35 days

Mixtures

Atomic™ Epoxiconazole +

Carbendazim Before direct grazing or feeding – 35 days

Fandango® Fluoxastrobin + Prothioconazole

Before direct grazing or feeding – 35–42 days

Mogul® Fluoxastrobin + Prothioconazole

Harvest for grain – 14 days Cut for forage – 35 days

Aviator Xpro® Bixafen +

Prothioconazole Cut for forage – 42 days

Adexar® Fluxpyroxad + Epoxiconazole


a Check individual labels for generic formulations of common fungicide brands to make sure that the correct label conditions apply. b SDHI= succinate dehydrogenase inhibitor.




9 Plant growth regulators

Key points:

The purpose of plant growth regulators is to improve the harvestability of crops for

silage, e.g. reduce lodging risk (all species), reduce height (triticale), improve straw

strength (barleys), improve quality (all species), improve green leaf retention (barley)

and raise head: stem ratio (all species).

Some evidence for improved ME in plant growth regulator (PGR) treated crops.

Withholding periods are critical as the best timing for application is close to the

permissible duration before silage harvest.

9.1 Overview and options, autumn and spring crops

Plant growth regulators are recommended in high yielding crops to increase stem strength and

reduce height by 15–20%. They reduce lodging risk in high fertility, heavy rainfall or high wind

situations, producing a high yielding, high quality crop and avoiding the need to reduce

harvesting speeds in a lodged crop. FAR trials on spring-sown grain barley have shown only

minor benefits from applying PGR, and similar results have been observed in spring barley

silage trials. Recent trials with PGR application have been extended to autumn-sown cereal

silage crops to determine effects on yield and quality.

The standard recommendation for triticale, wheat and barley is Moddus® (200 mL/ha) and

Cycocel® (1.5 L/ha) at 1st node (GS31 or GS32 if missed). Trial results with triticale and wheat

have shown that ME can be increased by up to 0.5 MJ/kg with use of growth regulators. Timing

is critical in spring-sown crops.

PGRs are most effective on tall crops and least effective on barley. They are best applied to

actively growing unstressed crops, and care needs to be taken with used of Terpal® as there is

a potential residue issue with late applications on WCS.

9.2 Supporting data for PGR chemical treatments

9.2.1 Spring trial 2012–13

In the 2012 irrigated ‘Monty’ spring barley trial, Moddus® was tested for its potential effect on

green leaf retention and on the rate of crop dry down through the harvest window. Results were

not conclusive for an application of 0.4 L/ha of Moddus at GS30 and there was no effect on

yield.

Treatment with Moddus at GS31 and Terpal at GS50, gave slight improvements in the energy

value of herbage. The effect was because of a change in grain to straw ratio. Stem length

reductions of up to 20 cm have been recorded for triticale. There was no height reduction in

barley, but there was a small response in wheat. PGR chemicals increased the yield of ME per

hectare in triticale but not in wheat or barley.




9.2.2 Autumn trial 2014–15

PGR was applied at ‘high’ or ‘low (control)’ rates (Table 10) with combination of chemicals

customised for each of the cereal species. PGR rate did not affect the yield in any of the

cultivars tested despite some obvious effects of PGR on crop height (Figure 3). However, in the

wheat cultivars selected for tall stem length (‘Wakanui’ and ‘Raffles’), the head:stem ratio was

improved with PGR applied at GS30–GS31 by shortening plant height. Higher head:stem ratio

increased overall feed quality, with no reduction in total yield (Figure 4). No lodging was

observed during the harvest window in any of the plots. PGR withholding periods are given in

Table 10.

Table 10. Plant growth regulator (PGR) treatments for the 2014–15 autumn sown trial in Lincoln.

Species Treatment Cultivar Plant growth regulator treatment a

Wheat 1 ‘Wakanui’ Nil

Wheat 2 ‘Wakanui’ 2.0 L/ha CCC® + 0.4 L/ha Moddus® (GS30-31)

Wheat 3 ‘Torch’ Nil

Wheat 4 ‘Torch’ 2.0 L/ha CCC + 0.4 L/ha Moddus (GS30-31)

Wheat 5 ‘Raffles’ Nil

Wheat 6 ‘Raffles’ 2.0 L/ha CCC + 0.4 L/ha Moddus (GS30-31)

Wheat 7 ‘09-25’ Nil

Wheat 8 ‘09-25’ 2.0 L/ha CCC + 0.4 L/ha Moddus (GS30-31)

Wheat 9 ‘12-45’ Nil

Wheat 10 ‘12-45’ 2.0 L/ha CCC + 0.4 L/ha Moddus (GS30-31)

Triticale 11 ‘Prophet’ 2.0 L/ha CCC + 0.4 L/ha Moddus (GS30-31)

Triticale 12 ‘Prophet’ 2.0 L/ha CCC + 0.4 L/ha Moddus (GS30-31)+ 0.2 L Moddus (GS32)

Barley 13 ‘Sanette’ 2.0 L/ha CCC + 0.4 L/ha Moddus (GS30-31)

Barley 14 ‘Sanette’ 2.0 L/ha CCC + 0.4 L/ha Moddus

(GS30-31)+ 1.0 L Terpal (GS37-39)

Oats 15 ‘Coronet’ Nil

Oats 16 ‘Coronet’ 2.0 L/ha CCC + 0.4 L/ha Moddus (GS30-31)

aCCC= chlorcholine chloride (Cycocel).




Figure 3. Adjacent plots of ‘Raffles’ wheat with 2.0 L/ha Cycocel® + 0.4 L/ha

Moddus® applied at GSS31 (right) and nil (left).

Figure 4. Dry matter (DM) yield (t DM/ha) for autumn-sown cultivars

harvested at 38%DM from the 2014–15 season in Lincoln. Data

shown as partitioned head and ‘stem + leaf’ for the plus and minus

growth regulator treatment means for each cultivar. ‘Sanette’,

‘Coronet’ and ‘Prophet’ are barley, oat and triticale cultivars,

respectively, and the remaining cultivars are wheats.

0

5

10

15

20

25

30

Dry

ma

tte

r yie

ld (

t/h

a)

Head Stem+Leaf




Table 11. Withholding periods for commonly used plant growth regulators for forage/silage

production.

Product Active Ingredient Withholding period for forage/silage

Terpal® Mepiquat chloride + Chlorethepon None listed

Moddus® Trinexapac-ethyl 42 days for ryegrass, none listed for cereal

Cycocel® 750 Chlormequat chloride 42 days, not registered for barley (or triticale?)

There were some small improvements in quality at silage maturity with PGR treatment (de

Ruiter et al. 2016).

9.2.3 Autumn trial 2015–16

Cultivar and PGR treatments were compared for effects on yield, timing of harvest and

profitability. The wheat cultivars (‘Wakanui’, ‘Raffles’, ‘Torch’, 09–25 and 12–45), were selected

to cover a range of maturities and plant heights, and compared with forage oats (‘Coronet’),

barley (‘Sanette’) and triticale (‘Prophet’).

Plant growth regulators (Table 11 and 12) had little influence on yield at early green chop or

silage maturity harvests, but did change some indicators of partitioning in the crops, confirming

results in the previous season (de Ruiter et al. 2016). Use of PGRs to control plant height had

little real impact on yield and crop profitability but had some effect on the proportions of plant

components and therefore on quality. There were significant effects of cultivar and PGR on

harvest index (p=0.009) and grain size (p=0.012) and significant effects on partitioning among

plants parts (leaf, stem and heads). The relative differences between cultivars was not always

consistent, making it difficult to interpret the physiological responses.

Table 12. Experimental treatments for autumn silage trial (2015–16) to assess yield variation

and harvest timing of autumn-sown cereals. Sowing was 8 May 2015, Canterbury.

Treatments Details

Trial entries

Barley (‘Sanette’)

Triticale (‘Prophet’)

Wheat (09–25, 12–45, ‘Torch’, ‘Raffles’, ‘Wakanui’)

Oats (’Coronet’)

Plant growth regulators (PGRs)

Control PGR treatment

Triticale: GS 30; 2.0 L/ha Cycocel® (a.i. chlormequat chloride) + 0.4 L/ha Moddus® on 14 September 2015 Barley: GS 31; 2.0 L/ha Cycocel + 0.4 L/ha Moddus on 14 September 2015 No PGR was applied to wheat or oats + PGR treatment

Wheat: GS 31; Cycocel at 2 L/ha plus 0.4 L/ha Moddus on 25 September Triticale: GS 30; Cycocel + 0.4 L/ha Moddus GS 32; Moddus at 200 mL/ha applied on 6 October Barley: GS 31; Cycocel at 2 L/ha plus 0.4 L/ha applied on 25 September GS 37; Terpal® at 1 L/ha on 9 October Oats: GS 30; 2.0 L/ha Cycocel + 0.4 L/ha Moddus applied on 25 September 2015




10 Irrigation

Cereal crops with full ground cover require 4–5 mm/day water in summer. Irrigation is

recommended when the soil moisture deficit exceeds 60 mm on light soils and 150 mm

on heavy soils.

Approximately 25 mm of water is used to produce 1 tonne of dry matter.

Irrigation during grain filling will ensure that grains are filled to potential and therefore

ensure that crops have both a high yield and high ME value. In severe drought

conditions grain size can be halved, reducing the yield and quality.

Irrigation amount and frequency affect the efficiency irrigation. Small amounts applied

often as in centre pivot irrigations (e.g. 25 mm/week) is better than larger amounts

applied less frequently (e.g. 50 mm/2 weeks), especially on light soils.

11 Environmental effects on crop growth

11.1 Soil and air temperature

Cereals can be sown in any soil temperature and have frost tolerance during emergence and

early development. After germination, crop growth is comparatively slow at temperatures below

4ºC. Crops sown later will develop faster and yield less, with barley being slightly less tolerant of

cooler soil temperatures than wheat or triticale. Crops at flowering can be affected by

unexpected frosts in November/December, causing loss of individual florets within an ear, and

reduced fertilisation, but this is rare for spring-sown crops. High temperatures at any time,

especially during grain filling, will hasten crop maturity and reduce yields and quality.

11.2 Rainfall

Excess rain and drought, can both influence yield and quality of WCS. Soil moisture deficit has

effects on leaf size during leaf development and causing early leaf death and reduction in grain

size. Excess soil water in early development stages strongly reduced growth in barley, but

wheat and triticale is less affected. Excessive rainfall can cause the freely available nitrate N to

be leached from the root zone, causing yield loss and potential environmental pollution.

11.3 Radiation

Solar radiation is the main driver for yield accumulation in cereal crops, so it is important to

maintain a healthy crop canopy for maximum light interception. Up to 80% of the yield can come

from the solar radiation intercepted by the top three leaves. Flag leaves in wheat and triticale

have a high proportion of the functional leaf area, whereas in barley the flag leaf is small that

the lower leaves and therefore a higher amount of light interception by lower leaves, especially

in erect leaf and culm types. If solar radiation is reduced during the maximum growth period

(November–January) then yields will be equally reduced.




12 Harvest timing and harvest methods

Key points:

WCS quality is dependent on harvest when crop has achieved near maximum grain fill

and there is sufficient whole crop moisture for ensiling.

WCS is best harvested when the crop is between 35–40% total DM, with an optimum at

38%DM.

Crop species and cultivars differ in the rate of whole crop dry down.

All studies on %DM change during maturation have shown linear changes in %DM in

response to thermal time beginning at GS49 and progressing through to >50%DM.

Starting values for %DM are dependent on current growing conditions (soil moisture,

weather pattern) and cultivar/species.

The benefits of using Roundup® to accelerate or synchronise crop dry down were

limited as there is a potential yield cost. In rare situations of excessive green matter with

premature grain maturation use of Roundup may be warranted.

Maximum soluble sugars and starch (SSS) occurs at 40%DM of WCS.

Inoculant use is mandatory to promote ideal fermentation pathways and improve

fermentation efficiency and reduce aerobic deterioration on silage opening.

Fine chopping improves the compaction and therefore air exclusion in silage making.

Timely application of irrigation, NN fertiliser, fungicides and PGRs can be used to improve the

consistency of WCS quality (FAR 2002b, 2002d, 2007). These management options improve

green leaf retention and may change the rate and duration of crop dry down. High quality is

achieved by the harvested crop when there is sufficient crop moisture for ensiling, and the crop

has achieved a high level of grain fill (FAR 2002e, 2004). Windows for ‘safe’ harvesting for

silage need to be extended to reduce the risk of poor silage quality. Barley silage crops provide

a challenge for achieving best yield and quality (FAR 2004), as the optimum harvest window for

silage is very short.

Cutting at the correct whole crop percent dry matter (%DM) content is important for ensuring the

best quality for ensiling. The %DM influences compressibility and air exclusion from the silage

stack during rolling. Optimum %DM content at harvest will help minimise dry matter losses

during ensiling. As the crop standing biomass progresses rapidly though the drying stages

during late grain filling, the harvest window may be as short as 3–4 days for barley and 7–10

days for triticale, wheat and oats. WCS is best harvested when the crop is between 35–40%

total dry matter, with an optimum at 38%, when the grain from the mid-ear position is

green/yellow colouration and with a ‘soft cheddar’ texture (GS86). The %DM can change by as

much as 1% per day for triticale, wheat and oats and by 2% per day for barley, during natural

dry down. The ME value can increase by up to 0.25 MJ/kg per week but will decline when

starch accumulation is complete (at 40%DM in grain). This decline is associated with reduced

digestibility as the crop matures.




12.1 Decisions on harvest time – yield and quality

changes near maturity

Variation in time to harvest occurs in response to varying weather conditions. Therefore,

adjustments to the harvest date will be required for periods of wet or dry conditions during grain

filling. Typical patterns of dry matter and quality change for wheat and barley during grain filling

is shown in Figure 5. Changes in key quality indicators from booting through to the end of grain

development mean that the optimum timing for harvest is toward the end of grain filling, when

total soluble sugars + starch are at a maximum. This occurs in synchrony with changes in ME,

but is associated with declining protein and digestibility (Figure 5).

Figure 5. Conceptual pattern of yield and quality changes during the

booting to hard dough period. Units for metabolisable energy are MJ/kg dry

matter (DM). Yield is % relative to maximum at maturity, and digestibility is

%DM. The shaded area is the extended dry matter range (38–46%DM) for

ensiling. SSS = total soluble sugars + starch.

Between flowering and harvest, the protein content declines from 14% to 7% and it is possible

that late application of N fertiliser may slow this decline during grain filling. However, the protein

content of WCS is generally not high enough to maintain non-limited milk production if pasture

quality is low.

Total soluble carbohydrates (including starch) (SSS) progressively increases from 12% at

flowering to approximately 22% at maturity (Figure 6). This fraction is the main source of energy

value of WCS. The increase in SSS continues until the crop DM% reaches 40% (Figure 6),

which coincides with the end of grain filling. Energy as reported in ME (MJ/kg) is relatively

stable during grain filling although some small increases have been measured followed by a

decline toward maturity. This decline may not be real since the ME reported using near infrared

spectroscopy (NIRS) is invariably calculated from digestibility, which does decline during grain

filling, but other factors including the starch fraction contribute to the true ME. A discussion on

the under-estimation of ME in WCS is given in Section 12.1

6

8

10

12

14

16

18

20

22

0

10

20

30

40

50

60

70

80

90

100

20 25 30 35 40 45 50

% D

M o

r M

E (

)

Dig

esti

bili

ty a

nd

Yie

ld %

(

)

Development stage (%DM)

Digestibility

Total SSS

Metabolisable energy




Figure 6. Relationship between dry

matter content and total soluble

carbohydrates (soluble sugars +

starch) in spring barley whole crop

during grain filling. Solid line indicates

regression for dry matter content up to

40% only.

12.2 Development stage vs physical indicators for

harvest timing

The rapid change in whole crop %DM as the crop matures and a decline in overall quality with

maturation means there is a narrow ‘harvest window’. If in doubt, the crop should be harvested

early rather than late, as the potential losses can be significant if the silage is made when too

dry. Inadequate compaction, incomplete fermentation, aerobic losses and grain shattering are

main causes of losses. Yield loss from incomplete grain filling may occur with early cutting, but

this is preferred to poor fermentation and the associated waste that can occur with harvesting

too late.

Variation in time to harvest occurs in response to varying weather conditions. Therefore,

adjustments to the harvest date will be required for periods of wet or dry conditions during grain

filling. Typical patterns of dry matter change for wheat and barley during grain filling is shown in

Figure 7. All studies on dry matter change during maturations have shown linear changes in

%DM, beginning at GS49 and progressing through to >50%DM, occurs at a linear rate in

response to thermal time.

Crop dry down, as shown for indicator plot treatments (Figure 7) were best fitted with a

quadratic response to calendar days. Crops dried down at an increasing rate and passed

through the ideal silage harvest window of 35–45%DM in a 7-day period. This left little

opportunity for managing the silage harvest, and it appears that agronomic treatments designed

to extend or delay the harvest window were not particularly effective (de Ruiter and Maley

2013). Of note is that the rate of dry down is a comparatively stable parameter within crop

genotype. The effect of environmental conditions or management treatments is on the starting

%DM (at GS49). This then allows prediction of the subsequent dry down rate and therefore a

projected harvest date given information about the accumulated daily mean temperature in the

dry-down period. Over a longer term, this is also a conservative parameter giving some

certainty on the timing of projected harvest. Intermediate updates on the current state of %DM

may be used to fine-tune a predicted timing harvest (i.e. at 38%DM). A computer model utility

has been developed to assist in harvest timing prediction that also includes an economic

0

5

10

15

20

25

30

35

0 20 40 60 80

Dry matter content (%)

Carb

ohydra

te (

%)




analysis for grain or silage costs taking into account all management inputs, and calculating the

net return for selected end use (de Ruiter et al. 2007).

Figure 7. Progress of % dry matter (DM)

change during grain development for

‘Boss’ barley in Canterbury in response

to calendar days (A) and accumulated

thermal time (B, 2012–13; C, 2013–14).

In Figure A, data were fitted with a

quadratic function. In Figure B, data

were fitted to a linear model for values

below an observed threshold of

50%DM. Values between the limits 30–

50%DM represent the absolute range

for silage making. The ideal dry matter

content for silage is 35–45%. In C,

respective treatments were low (50 kg

N/ha), medium (50+50 kg N/ha) and

high (50+50+50 kg N/ha) fertiliser rates.

An example of crop dry down response is shown in linear trends when whole crop %DM is

plotted against accumulated thermal time with a reliable prediction range (20–45%DM),

(Table 13; Figure 7B). At >50%DM there was a transition into a higher rate, which has not been

repeated in other studies. Mostly, the dry down response is linear for the duration of dry down.

However, the initial dry down parameters were useful for predicting crop maturation with

termination at the upper end for ideal silage making (40–50%DM). There was no difference in

rate of dry down for the selected treatments. Differences due to N treatments were explained

solely by the starting %DM, and there were generally no differences in dry down for fungicide or

PGR treatments in the Canterbury site (Figure 7) (de Ruiter et al. 2013; de Ruiter and Maley,

2013). At other South Island sites, some effects of management were found to be effective in

changing the starting %DM. For example, at the Lincoln irrigated trial and Southland sites, both

N fertiliser and fungicide affected the starting %DM pattern of dry down. At two other sites and

0

10

20

30

40

50

60

70

80

90

0 5 10 15 20 25 30 35 40 45 50 55 60

Dry

mat

ter

(%)

Days after ear emergence

Irrigated -N

Irrigated +N

Dryland -N

Dryland +N

A

0

10

20

30

40

50

60

70

80

90

0 100 200 300 400 500 600 700 800 900 1000

Dry

mat

ter

(%)

Thermal time after ear emergence ( Cd)

Irrigated -N

Irrigated +N

Dryland -N

Dryland +N

B

10

20

30

40

50

60

70

Dry

mat

ter

(%)

Thermal time after ear emergence (°Cd)

Irrigated Trt 1 Dryland Trt 1



C




Lincoln dryland, fungicide was ineffective in changing the initial %DM for treated crops. Irrigation

and dryland treatments were different in the 2013–14 trial, but contrary to the previous season,

N treatments showed little different in dry-down characteristics (Figure 7C).

Table 13. Parameter values and errors for linear regressions relating %DM (dry matter) with thermal

time after ear emergence for crops of ‘Boss’ barley grown under dryland or irrigated conditions in

2012–13. Parameters are given for models with differing intercepts (α) and common slope (β)a.

Parameters and standard errors of estimates

Site N treatment a Intercept (α) se (α) Slope (β) se (β)

Dryland b

N1 (50 kg N/ha) 21.21 0.424

N2 (100 kg N/ha) 20.70 0.496 0.0418 0.0012

N3 (200 kg N/ha) 18.63 0.431

Irrigated c

N1 (50 kg N/ha) 20.21 0.379

N2 (100 kg N/ha) 17.42 0.409 0.0370 0.0008

N3 (200 kg N/ha) 15.45 0.386

a Variance due to N treatment within site was significant at p<0.001; b Effects of fungicide and plant growth regulator were not significant

(p>0.05); c Effect of fungicide was not significant (p>0.05) for a linear model y= α + βx.

A similar analysis was done for a spring trial (2012–13) and data for the drying rates for differing

N fertiliser treatments within irrigated and dryland barley blocks are given in Table 13. The

derived linear relationships allowed prediction of ideal harvest date (i.e. when the reaches

38%DM). This enabled predictions to be made as early as GS49, some 30 to 57 days before

harvest. Barley, wheat and triticale had quite different durations from GS49 to ideal silage

maturity (38%DM), (Table 14).

Table 14. Expected number of days to silage harvest.

Cultivar

Date of awn tip

appearance

(GS49) a

Mean b

temperature

(°C)

Date for whole crop to reach dry matter content of

32% 35% 38% 41% 44%

‘Boss’ barley 1 Dec 16 26 Dec 30 Dec 3 Jan 7 Jan 11 Jan

1 Jan 17 25 Jan 28 Jan 1 Feb 5 Feb 8 Feb

‘Rocket’ triticale

1 Nov 13 11 Dec 19 Dec 26 Dec 3 Jan 10 Jan

1 Dec 16 3 Jan 9 Jan 15 Jan 21 Jan 27 Jan

1 Jan 17 1 Feb 6 Feb 12 Feb 18 Feb 23 Feb

Sapphire’ wheat

1 Nov 13 3 Dec 8 Dec 14 Dec 19 Dec 24 Dec

1 Dec 16 27 Dec 31 Dec 4 Jan 9 Jan 13 Jan

1 Jan 17 25 Jan 29 Jan 2 Feb 6 Feb 11 Feb

a GS = growth stage; b Mean temperature in the 15-day period after awn tip appearance.




12.3 Synchronising harvest timing

Roundup™ is a possible option for synchronising harvest timing in forage cereals. There is also

anecdotal evidence that treatment with Roundup can increase the soluble sugar content of the

crop and therefore affect quality. However, there is also the possibility that desiccation

treatments will stop grain filling if applied too early and therefore reduce quality.

Application is ideally around the whole crop 30%DM stage, so that its effect is apparent when

the whole crop is in the range of 38–45%DM. A crop desiccation experiment (2013–14) involved

application of glyphosate (either 1 L/ha or 3 L/ha) at 30%DM and at 3-day intervals thereafter.

Figure 8. Progress of percent dry matter (%DM) change for two Roundup treatments (1 L/ha and

3 L/ha Roundup) with applications at 30%DM (A); and at 4 days (B), 7 days (C) or 11 days (D) after

the crop reached 30%DM, respectively.

Whole crop dry matter increased in all cases with application of Roundup compared with the

control (untreated). Visual leaf colour changes were observed within 4 days of application and

continued to dry down at a faster rate than untreated crop (Figure 8A to 8D). The rate of %DM

change was strongly related to thermal time accumulation using a time ‘zero’ from the point of

application. These responses can be used predictively to estimate expected thermal duration to

harvest time but the rate response was dependent on the timing of application. Therefore,

without further work detailing the response rates over time, there appears to be little value in

trying to predict when a crop will be at the ideal developmental stage for harvest. If Roundup is

used to accelerate drying, then the best approach is to monitor the crop closely and proceed

with harvest when there is still some green leaf area remaining and the whole crop DM% is in

the appropriate range (35–45%DM).

10

20

30

40

50

60

70

80

0 100 200 300 400 500 600 700 800

Dry

mat

ter

%

Timing 1, 1 L/ha

Timing 1, 3 L/ha

Control

Timing 1

A

10

20

30

40

50

60

70

80

0 100 200 300 400 500 600 700 800

Timing 2, 1 L/ha

Timing 2, 3 L/ha

Control

Timing 2

B

10

20

30

40

50

60

70

80

0 100 200 300 400 500 600 700 800

Dry

mat

ter

%


Timing 4, 1 L/ha

Control

Timing 4

D

10

20

30

40

50

60

70

80

0 100 200 300 400 500 600 700 800

Dry

mat

ter

%


Timing 3, 1 L/ha

Timing 3, 3 L/ha

Control

Timing 3

C




A consequence of applying Roundup is that yield is prematurely halted because of the rapid

onset of senescence. There were significant rate (p=0.040) and timing (p=0.037) effects, but no

significant (p=0.79) rate x timing interaction (Figure 8). The final whole crop yield for the

respective Roundup timings spanning a 6-day period (at 30, 32 and 34%DM) were 10.4 11.6

and 12.5 t/ha; respectively. Therefore, if Roundup is used during a time when there is active

photosynthetic activity, there is a cost in total DM accumulation in the order of 2 t DM/ha, and

this will strongly outweigh any advantages in synchronising the harvest timing. Analysis of grain

yield showed there was a significant timing effect (p=0.026) with a 1 t DM/ha increase in yield

from early to late application. This difference was not accounted for by either harvest index or

grain number per ears. There was no effect of Roundup rate or timing on quality of silage.

12.4 Use of inoculants and chemical additives

Whole crop when cut for silage contains natural populations of bacteria that will assist the

anaerobic fermentation. Inoculants with desirable bacterial species increase the production of

acetic and propionic acid as fermentation end products, and reduce the activity of undesirable

(enterobacteria and clostridia) fermentation pathways. Specifically selected strains of lactic acid

bacteria can convert plant sugars more efficiently and are more competitive than bacteria and

yeasts already present on the plant. These are homofermentative strains, often from the

species Lactobacillus plantarum. Heterofermentative strains (Lactobacillus buchneri) produce

less heating on exposure to air on opening the silage. These types form the basis of silage

inoculants that can improve fermentation efficiency. Inoculants reduce dry matter and quality

losses that occur when stack management is not ideal. Inoculants are mostly added at the time

of cutting as a routine practice to:

a. Improve the fermentation, especially when used on low DM forages or legumes.

b. Reduce aerobic deterioration when the stack is opened.

c. Increase the concentration of acetic, propionic and lactic acid forming bacteria, and

reduce the activity of aerobic fungi (yeasts). To be effective, inoculants should be

applied at greater than 100,000 viable colony forming units per gram of fresh forage.

Using a good inoculant will supply large numbers of selected live bacteria capable of

efficient organic acid production under specific moisture, soluble sugar concentrations

and pH conditions. depending on the stage of fermentation.

Selected enzymes and silage stabilisers are also added to inoculants to release more nutrients

and to break down longer chain carbohydrates into fermentable forms. A list of silage inoculant

products on the market in New Zealand is given in FAR (2016a).

a. In later cut cereal crops (40–45%DM), soluble sugar levels may be low and these crops

may benefit from additives containing enzymes.

b. Chemical silage additives may also reduce aerobic deterioration between stack opening

and feed out.

c. Research data on WCS in experimental silos has shown positive benefits of inoculation

by promoting higher lactic acid and lower butyric acid (Table 14). Use of silage additives

has also been shown to improve intake, improve palatability and raise milk production.




Table 14. Effect of silage inoculant on pH and volatile fatty acid (VFA) composition of whole crop

silage (Plant & Food Research, Lincoln).

Cultivar Inoculant a pH Lactic acid Iso-butyric acid Total VFA

mg/g DM

‘Rocket’ triticale – 4.7 71 7.7 106

‘Sapphire’ wheat – 4.8 74 4.4 107

‘Boss’ barley – 5.0 73 1.5 102

‘Rocket’ triticale + 4.5 302 0 330

‘Sapphire’ wheat + 4.5 255 0 280

‘Boss’ barley + 4.8 262 0 282

a treatments were control (–) or inoculated (+).

12.5 Chopping

The chop length for WCS should be about 10–15 mm to assist with compaction (Figures 9 and

10). At this chop length, all the grain will be threshed from the heads, so attention should be

given to ensure high utilisation efficiency when feeding to limit the grain loss.

Figure 9. Finely chopped sample of ‘Rocket’

whole-crop cereal silage. Chopping to lengths

less than 2 cm will ensure good compaction.

Figure 10. A well compacted ‘Rocket’ triticale

silage stack showing flattened stem fractions.

12.6 Cutting height

Cutting height will determine the proportion of straw relative to the grain content (the grain to

straw ratio) in the final product. The ME of straw is 7.0–8.0 but the grain fraction exceeds

11.0 MJ/kg. The grain to straw ratio for well-managed WCS crops is normally around 0.50 on a

DM basis. Increasing the cutting height can increase the grain percentage with each 10 cm

increase reducing straw dry matter yield by approximately 1 tonne. Similarly, cutting height will

determine the amount of nutrients removed. Table 15 shows typical data for ME value of grain

alone.




Table 15. The metabolisable energy (ME) content of the grain fraction and the

percent of ME in the grain as a proportion of the whole plant.

Species ME of grain

(MJ/kg dry matter) % of ME in grain

Barley 13.8 65

Triticale 13.9 63

Wheat 14.5 48

Oats 11.0 32

12.7 Quality losses during ensiling

During ensiling, lactic acid bacteria convert soluble carbohydrates rapidly to lactic acid and

other short-chain organic acids with a reduction in pH to <4.5. This inhibits the growth of

clostridia that can cause protein degradation to ammonia, CO2 and amines. Harvesting within

the range (35–45%DM) will maximise the nutrient and energy value and the fermentation

characteristics, with minimum DM losses during crop processing and ensiling. This will also

minimise the microbial breakdown losses, e.g. protein degradation in the stack and reduce

secondary DM losses through aerobic deterioration (heating) after opening. Some

consequences of harvesting at differing %DM are given in Table 16.

Table 16. Features of ensiling at various moisture contents

DM (%) Description

20

Anaerobic fermentation

Protein degradation

High soluble Nitrogen

High (>10%) ammonia N as a proportion of total N

Potentially high butyric acid production

20–30

Requires wilting

Wilting reduces risks of clostridial fermentation

Relatively hard to ensile

30–35 Suitable for direct chop

Crop still short of yield maximum

35–40

Ideal for natural preservation

Presence of a suitable natural microbial population

Adequate amount of fermentable carbohydrate utilised by bacteria within 5 days of covering

With good compaction anaerobic conditions during fermentation will ensure good silage

40–45 Hard to ensile as it is springier and harder to compact

Water soluble carbohydrates may be lower than optimum

45–50 Oxidative fermentation and rapid loss of quality




12.8 Stack management

When WCS is exposed to air, various bacteria and yeasts that thrive in the presence of air

begin to consume soluble carbohydrates and sugars in the silage. The pH rises and the silage

starts to heat. As silage starts to deteriorate, dry matter is lost. This may be as little as 1% in

well-managed stacks and 3–5% or even more in poorly managed situations.

Disturb the face as little as possible when removing the silage from the stack. The use of a

shear grab is recommended. It is best to leave the face uncovered as re-sheeting overnight

forms a warm moist air pocket between the sheet and the face. Netting can be used to prevent

bird damage and spoilage of an open stack. Only feed out the amount required for immediate

consumption and do this as close as possible to when the cows are due to consume it.

If there is spoilage on the top or shoulders of the stack, this should be forked off for compost,

not fed to the stock with the silage. Any loose material at the base of the face should be tidied

up and fed out each day. Recent research showed that digestibility of fibre was significantly

reduced when small proportions (<5%) of spoilage were included in the silage ration.

13 Feed quality

Key points:

Protein content is lower in WCS than animal requirement in a complete diet. So WCS is

best used as a supplement to other primary feeds.

The ME range for WCS is 9.5–10.4 MJ/kg DM.

Cereals have moderate to low crude protein (CP) content, with means ranging from

9.2%DM (barley) to 14.1%DM (oats).

Barley, wheat and triticale silages had >90% of entries with a CP concentration less

than 16%.

The neutral detergent fibre (NDF) content ranges from mean of 44.8 (wheat) to

49.7%DM (barley).

Protein content and SSS are inversely correlated.

In vivo tests for ME have indicated that analysis of ME by NIRS results in an

underestimation of the true ME by as much as 1.0 MJ/kg DM.

In sacco digestion of barley WCS and comparisons with grass silage, maize silage and

lucerne hay showed that WCS has highest initial DM disappearance in the 0–20 h

period. Final DM disappearance was similar to maize silage. NDF disappearance was

also higher initially that the comparative crops indicative of a high soluble fibre fraction

in barley silage.

Mineral content of WCS is lower (except for K) than the requirements for ruminants.

Dietary cation anion difference (DCAD) is generally low (28–177 me/kg) and therefore

useful for managing milk fever, and stimulating Ca mobilisation in early lactation.




13.1 Forage quality indicators

Measurements of feed quality of WCS obtained from a spring sown trial at Lincoln are shown in

Table 17 (de Ruiter et al. unpublished).

Table 17. Mean yield and nutritive value of pre-ensiled herbage for whole crop silage. Data were

from trials conducted at Lincoln. Samples were taken at 38–45%DM.

Species a DM yield

(t/ha) ME b

(MJ/kg) Protein

(%) Total SSS b

(%) NDF b (%)

ADF b (%)

OM digestibility a

(%)

Triticale 17.2 10.1 7.9 26.0 41.4 24.6 70.4

Wheat 16.9 9.8 8.5 27.0 40.6 26.0 68.6

Barley 14.0 9.7 8.0 24.7 43.8 27.4 68.1

a mean of cultivars ‘Omaka’ and ‘Boss’ barley; ‘Sapphire’ wheat; ‘Rocket’ triticale. b ME = Metabolisable energy; SSS = total soluble sugars and starch; NDF = neutral detergent fibre, ADF = acid detergent fibre; OM =

organic matter.

Maintaining a high protein content of WCS is an advantage for rumen microbial growth, but high

protein is often not achieved for WCS. Readily fermentable carbohydrate and total fibre for

roughage are also important for efficient rumen function and WCS is a good source of these

forage quality components. The overall digestibility of the herbage has a strong influence on the

acceptability of the product to animals.

Spring or autumn pasture is usually high in protein and relatively low in fibre and water-soluble

carbohydrates. Cereal silage has a complementary profile to pasture and therefore an ideal

complementary feed in supplying soluble carbohydrates and fibre in a balanced ration in

ruminant diets.

If cows are fed high quality pasture ad lib, the WCS may substitute pasture at a rate exceeding

0.8 kg DM per kg of WCS intake and therefore will lower total ME intake. This underlines the

importance of aiming for a high digestibility (>70%) and high ME content (>10 MJ ME/kg DM) in

the WCS. In late lactation, or during wintering, it is still important but less critical.

The feed quality attributes of WCS make it an excellent supplementary feed for pastoral

livestock systems in New Zealand. The energy content is usually 1–2 ME units lower than grass

silage and up to 1 ME unit lower than maize silage. However, yield is much higher than grass

silage and often comparable to maize. Wide sowing date options for WCS adds to its flexibility

for its use in rotations compared with maize. Like maize, much of the feed quality of cereal

silage is derived from the grain component, so agronomic treatments and harvest timing options

need to be managed to achieve a high grain to straw ratio. Management of the crop also

extends to options that may affect the quality of the stem and leaf portions to enhance the value

of the feed at harvest. Cereal silage is a complementary feed to pasture, and its value as fibre

and starch source is underestimated. The energy value from soluble sugars and starch

compensates for the low protein content providing good balance with pasture that is already

high in protein. The high NDF content contributed from the stem and leaves help balance

pasture that that is sometimes too low in fibre (<35% NDF) for good rumen function.




13.2 Quality of WCS

The range and variability of forage quality for key cereal, grass and legume forages from

sample sets collected by Plant & Food Research over the last 15 seasons are summarised in

Table 18. In general, predictions of mean ME for cereals by ARL Laboratory, Napier were low

for barley (9.5 MJ/kg DM), wheat (9.6 MJ/kg), triticale (9.8 MJ/kg DM) and oats (10.4 MJ/kg

DM). The barley, wheat and triticale were all mature WCS, and oats were invariably taken at the

green chop stage. Occasionally, ME in excess of 10.7 MJ/kg have been reported for well-made

WC barley silage, thus similar to maize silage. Invariably, the ME values reported are well below

this and reasons for this are discussed in Section 12.1.

Cereals have moderate to low CP levels, with means ranging from 9.2%DM (barley) to

14.1%DM (oats). Oats were generally higher in protein as they were usually harvested at the

green chop stage compared with other cereals, which were taken through to whole crop silage.

In the database, cereal silage CP and soluble sugar and starch content (SSS) content varied

with cereal type. Barley, wheat and triticale silages had >90% of entries with a CP concentration

less than 16%. A high proportion of wheat and barley silage samples contained more than

25%DM as SSS; with triticale, oats and ryecorn having lower SSS content. Therefore, there is

potential for significant feed value in terms of protein and SSS content if crops are managed for

high quality, and cultivars chosen with high quality characteristics.

The NDF content in historical database entries (Table 18) ranged from a mean of 44.8 (wheat)

to 49.7 (barley), with invariably lower % organic matter digestibility (OMD) compared with

ryegrass, lucerne and maize. Low in vitro digestibility was the reason for low ME values as

these were calculated from linear functions of digestibility as predicted by NIRS, (Table 18).

Occasionally, ME values in excess of 10.7 MJ/kg have been reported for well-made WC barley

silage, thus similar to maize silage. Invariably, the ME reported is well below this. Anecdotal

evidence from farmer experience that animals generally perform better than expected given the

laboratory values reported for metabolic energy value (ME). A strong factor in the slow adoption

of WCS as a value fed for ruminant industries its sometimes erroneous assessment of ME.

A sample set of several thousand commercial silages from the South Island held at Lincoln

University showed that the mean ME value was between 10–11 MJ/kg DM, with WCS at the

lower end or below this range at 8–10 MJ/kg (Dalley et al. 2017). Resolving the feed quality

disparities would therefore likely restore WCS as a supplementary feed option and provide

further opportunities for more widespread use of WCS as a feed supplement.




Table 18. Means and standard deviations for herbage quality variables for entries in the Plant & Food

Research database of cereal, ryegrass, lucerne and maize. Values in parentheses are standard errors.

All samples were analysed by Analytical Research Laboratory (Napier).

Crop ADF Ash

Crude protein

Digest-ibility

Lignin DCAD

%, w/w me/100 g

Barley 27.4

(5.99) 6.1

(1.33) 9.2

(2.52) 57.4 (2.5)

4.0 (1.78)

345 (141.8)

Wheat 27.6

(5.40) 5.8

(2.29) 11.0

(3.55) --

3.8 (0.44)

123 (98.2)

Oats 28.5

(4.29) 8.9

(3.00) 14.1

(6.89) --

4.7 (0.98)

413 (167.7)

Triticale 29.0

(5.68) 6.4

(3.03) 11.1

(5.57) --

4.5 (1.16 )

226 (177.2)

Maize 18.6

(8.67) 3.4

(0.91) 13.8

(10.35) --

--

180 (35.4)

Ryegrass 25.8

(4.42) 8.7

(0.78) 15.2

(3.91) 67.7

--

366

Italian ryegrass 24.3

(2.78) 10.6

(1.70) 20.8

(5.95) --

3.8 (0.27)

661 (160.2)

Lucerne hay 39.5

(4.89) 7.8

(0.87) 14.8

(0.96) --

--

--

Crop Lipid NDF

Organic matter

digestibility Starch

Sol sugars

+ starch ME

%, w/w MJ/kg DM

Barley 2.9

(1.38) 49.7

(8.28) 67.3

(8.75) 23.6

(2.36) 23.9

(7.58) 9.5

(1.07)

Wheat 3.5

(1.91) 44.8

(8.74) 65.8

(7.06) 57.7

(8.42) 21.5

(9.10) 9.6

(1.21)

Oats 3.1

(1.67) 48.0

(7.31) 71.8

(10.22) 0.5 (-)

14.9 (4.19)

10.4 (1.43)

Triticale 2.8

(1.28) 48.5

(9.71) 66.6

(8.17) 5.9

(1.77) 19.3

(7.12) 9.8

(1.15)

Maize 2.6

(0.64) 43.0

(5.72) 80.8

(23.12) --

39.8 (5.29)

10.7 (0.61)

Ryegrass 2.7

(1.10) 44.6

(4.13) 67.0

(4.53) 0.5 (-)

11.8 (0.74)

10.7 (0.50)

Italian ryegrass 2.9

(0.90) 44.6

(7.03) 87.0

(8.79) --

17.0 (6.87)

12.7 (1.05)

Lucerne hay 1.0

(0.22) 51.2

(7.56) 72.4

(24.12) 0.5 (-)

4.7 (2.15)

8.0 (0.90)

ADF = acid detergent fibre; DCAD = Dietary cation anion difference; ME = metabolisable energy; NDF = Neutral detergent fibre.

Comparison of protein and total soluble sugar + starch (SSS) levels in WCS crops (de Ruiter et

al. 2013) showed that there was a strong inverse relationship between these variables. This can

be explained by a dilution effect of soluble sugar and starch accumulation during grain fill

combined with a reduction in N uptake in the later growth stages resulting in a reduction in the

C/N ratio with maturation. Protein and total SSS composition for a barley trial at Lincoln harvest




at beginning, middle and end of the silage harvest window are given in Figure 11. Within time

event or irrigated vs dryland treatment there is a net substation of protein and SSS. Also, over

time the SSS continues to increase throughout the harvest period (32–45%DM) commensurate

with an overall decline in the mean protein content.

Figure 11. Relationship between protein content of barley silage (‘Monty’) and the soluble sugar and

starch content for successive harvests: H2 (A, D), H3 (B, E) and H4 (C, F) spanning the silage harvest

window. Respective harvests were taken when plots reached 32, 38 and 46%DMdry matter. Data

points are for individual plots within the irrigated (A, B, C) and dryland (D, E, F) block.

A summary of all data for quality (SSS and protein) of whole crop silage in the seasons 2012–

13 to 2015–16 is given in Figure 12. The overall mean SS was 25.8% DN and protein 9.0%DM.

Figure 12. Pooled data for relationship between total soluble carbohydrates

and starch (SSS) and protein for multiple WCS trials (2012–13 to 2016–17).

Box plots indicate the median, 25–50 and 50–75% quartiles; and points are

<10% and >90% frequency distribution.

y = -0.3805x + 16.077R² = 0.63

4

6

8

10

12

14

0 5 10 15 20 25 30 35 40

Pro

tein

(%

)

Soluble sugars + starch (%)

A: Lincoln irrigated, H2

y = -0.1926x + 13.244

R² = 0.37

4

6

8

10

12

14

0 5 10 15 20 25 30 35 40

Pro

tein

(%

)


B: Lincoln irrigated, H3

y = -0.1819x + 12.639

R² = 0.41

4

6

8

10

12

14

0 5 10 15 20 25 30 35 40

Pro

tein

(%

)


C: Lincoln irrigated, H4

y = -0.4807x + 20.33R² = 0.59

4

6

8

10

12

14

0 5 10 15 20 25 30 35 40

Pro

tein

(%

)


D: Lincoln dryland, H2

y = -0.3106x + 17.575R² = 0.63

4

6

8

10

12

14

0 5 10 15 20 25 30 35 40

Pro

tein

(%

)


E: Lincoln dryland, H3

y = -0.1758x + 12.829

R² = 0.26

4

6

8

10

12

14

0 5 10 15 20 25 30 35 40

Pro

tein

(%

)


F: Lincoln dryland, H4

r = 0.70

Protein (%)

2 4 6 8 10 12 14 16 18

Solu

ble

Su

gars

an

d S

tarc

h (

%)

10

15

20

25

30

35

40

45

Protein (%)

2 4 6 8 10 12 14 16 18

Solu

ble

Su

gars

an

d S

tarc

h (

%)

10

15

20

25

30

35

40

45




When data was partitioned for management factors influencing this relationship, there were only

small shifts in the relationship. There was little difference wheat and triticale (Figure 13A);

however, the difference between geographical location (Canterbury and Southland) was

significant (Figure 13B). Likewise there were similar shifts related to PGR treatment vs no PGR

(Figure 13C); and spring vs autumn-sown crops (Figure 13D).

Figure 13. Effect of crop management (A: species selection; B: location, C: plant growth regulator

(PGR) treatment, and D: spring and autumn sowing) on the relationship between total soluble

sugars and starch and crude protein).

13.3 Validation of ME of whole crop silage

Digestibility tests on fibrous cereal feeds have historically shown results that are inconsistent

with observed animal responses and therefore are not represented fairly in NIRS predictions of

ME. WCS shows lower lab-based ME than expected when compared to in vivo animal

performance. Net ME was determined by calorimetry with correction for methane and excretion

losses to determine the true ME of a WC barley silage. Results were compared with ME

determinations by NIRS prediction in three commercial labs (de Ruiter and Gibbs 2017. The in

vivo digestibility validation is rarely done because of the high cost of animal digestion

experiments in metabolism crates, but was necessary to validate WCS barley silage quality

against other feed standards (e.g. maize silage, pasture silage and lucerne hay).

Digestibility tests on fibrous cereal feeds have historically shown results that are inconsistent

with observed animal responses and therefore are not represented fairly in NIR predictions of

ME. WCS, in particular, shows lower lab-based ME than expected compared to in vivo animal

performance. Net ME was determined by calorimetry with correction for methane and excretion

losses to determine the true ME of a WC barley silage. Results were compared with ME

determinations by NIRS prediction in three commercial labs (de Ruiter and Gibbs 2017. The in

10

15

20

25

30

35

40

45

50

0 5 10 15 20So

lub

le S

uga

rs a

nd

Sta

rch

(%

)

Crude Protein (%)

Barley

Wheat

Triticale

B

10

15

20

25

30

35

40

45

50

0 5 10 15 20

Solu

ble

Su

gars

an

d S

tarc

h (

%)

Crude Protein (%)

Canterbury

Southland

r = 0.72

r = 0.71

A

10

15

20

25

30

35

40

45

50

0 5 10 15 20

Solu

ble

Su

gars

an

d S

tarc

h (

%)

Crude Protein (%)

Control ( - PGR)

+PGR

D

10

15

20

25

30

35

40

45

50

0 5 10 15 20

Solu

ble

Su

gars

an

d S

tarc

h (

%)

Crude Protein (%)

Spring-sown

Autumn-sown

C




vivo digestibility validation is rarely done because of the high cost of animal digestion

experiments in metabolism crates, but was necessary to validate WCS barley silage quality

against other feed standards (e.g. maize silage, pasture silage and lucerne hay) with proven

calibrations for ME as predicted by NIRS. This was followed by assessment of in sacco

digestion characteristics of the four feed within a background feed diet comprised of base feeds

supplemented with standard straw and green pasture. The design was four dietary feed

allocations x four animal assignments replicated in four in consecutive feeding periods. In sacco

feed incubations were arranged so that each feed was represented within each animal with

bags removed at timed intervals from 4 hours to 72 hours of incubation.

13.3.1 Feed sample preparation

Methods used to prepare WC barley and maize silage were prepared as follows: Bulk silages

were extracted from on-farm silage stacks and transported to a packing shed where 20 kg FW

bags (120 micron) were evacuated, and residual air partially replaced with CO2 then sealed with

a thermal press while under suction. This ensured a stable gaseous environment and long term

preservation with consistent quality of silage for the duration of the feeding experiment. Initially,

the bags were stored at room temperature and mid-way through the experiment they were

transferred to a walk-in refrigerator to ensure stability. There was little visible aerobic

deterioration of the silage for up to 6 months after bagging.

Samples for animal testing were prepared as either as bagged silage (barley and maize), or

bulk lucerne hay or stack pasture silage. This material was used for diet evaluation in two

experiments: (1) with sheep to determine the comparative true digestibility and ME value of the

four feeds in open pens where total urine and faecal collection and methane production were

measured; and (2) with steers to determine the NDF fibre digestion and in vivo digestibility of

the four feeds.

13.3.2 In vivo digestion study– sheep

Diets for an in vivo digestion study using sheep were comprised of varying proportions of cereal

silage supplemented with lucerne hay. Eight sheep were fed four diets in four repeat runs over

time, with increasing WCS content in the diet. The feed sequence started with 100% lucerne

hay, then 50% lucerne hay + 50% WCS, then 15% lucerne + 75% WCS, then 100% WCS. All

the diets were fed at maintenance energy intakes and the N intake was kept constant across all

diets using supplementary urea. The diets were fed for 14 days initially to adjust the sheep to

the new feed, then faecal and urine collections were undertaken for 7 days in each trial. Net

energy of the feed was calculated using calorimetry and corrections made for the energy loss in

methane. The net ME from feed intake less excretion and methane output was determined for

the combined feed and corrected for WCS component alone and determination of an ‘apparent

% dry matter disappearance (DMD%) for replicate sheep for the 7-day measurement period.

Similarly, both digestibility of organic matter in dry matter (DOMD%) and NDF digestibility was

obtained by calculation. A calculation of the ME of the diets was also made from the DOMD%

values, using both a range of expected methane energy emissions, and a third estimate simply

from a ryegrass pasture-based formula used widely in New Zealand, namely DOMD% x 0.16 =

ME (MJ/kg DM).

The sheep digestion experiment showed that the ‘true’ ME value of WC barley silage was

between 10.1 and 10.6 MJ/kg. This is the first known calculation of ‘true’ energy value of whole

crop silage from in vivo experimentation in New Zealand. Predictions of ME have historically




been made by analytical labs using NIR calibrations based on grass standards, and often low

values have been reported. This has resulted in farmer distrust in the value of WCS.

The animal digestion experiment confirmed that WC barley silage was an equally valuable

supplementary feed source as maize. The WCS ‘true’ ND fibre digestion and DM digestibility

are comparable if not higher than maize.

13.3.3 In sacco digestion study – steers

The second experiment with two fistualed steers in each of four silage diets (pasture silage

alone, maize silage + pasture silage, lucerne hay + pasture silage, and WC barley silage +

pasture silage) was used to determine the in vivo digestibility of the supplement component.

Each feed was supplied as 25% supplement and 75% grass silage in the respective mixes.

These ratios were based on standard allocations used to determine differences between

supplement (treatment) feed samples.

Maize silage and barley silage samples for in sacco digestion by steers were prepared in the

same way as lucerne and pasture samples, by freeze drying and grinding to pass a 4 mm

screen. Well mixed 5 g (DW) samples in triplicate were weighed into nylon mesh bags.

Triplicate bags of each treatment feed were recovered from each cow at 3, 6, 9, 12, 24, 48 and

72 h of incubation. On removal, the bags were rinsed, washed for 30 minutes in a cold cycle

washing machine, and oven dried for 48 h, to a constant weight. They were then weighed, and

bulked within sampling time and within cow. The samples were then ground to pass a 1 mm

screen and analysed for NDF content using an ANKOM analyser (ANKOM reference manual).

The WCS used in the nylon bags and fed to the cows was identical to that used in the sheep in

vivo trials, to enable a comparison of total tract digestion and time series DM and NDF

degradation.

13.3.4 Laboratory testing

Barley silage ME reported by laboratory near infrared methods was under-estimated by

Laboratory 1 relative to the others, whereas other crops and pasture components were slightly

over-estimated. Maize results appeared to be relatively consistent over three laboratories.

There was evidence for a breakdown of prediction rigour when NIR predictions of ME were

compared with a ‘Wet Chem’ value produced by Laboratory 1. The reported ME by ‘Wet Chem’

is itself a prediction based on sample digestion, so there was potential error introduced by

relating an in vitro derived or NIRS-derived digestibility to ME. Moreover, the relationship

between digestibility and ME is an empirically derived one and not validated against an in vivo

ME. The in vivo digestion results from this study provide confirmation of the ’real’ ME value of

barley silage and a correction is justified that raises the NIRS predicted value reported in

historical quality test by an average of 1 unit of MJ/kg.

Metabolisable energy derived from ‘Wet Chem’ quality indicators (Laboratory 1) did over-

estimate the NIR-based ME predictions by other laboratories for barley silage. Lucerne silage

and pasture silage were over-estimated. This amplified the difference between barley silage and

other feeds and further disadvantaged barley silage against other feeds when using NIR to

predict ME but over-estimated ME when using in vitro ‘wet chem’ predictors. The animal

digestion experiment showed that barley silage was in fact a better feed than laboratory testing

indicated, and that the dry matter disappearance (Figure 14) and NDF disappearance (Figure

15) during in vivo digestion was superior to maize silage. Further work is needed to better




understand the fraction that was rapidly solubilised in the in vivo animal trials and which should

be accounted for in the lab-based estimates of feed value of WCS.

Figure 14. The mean (of eight cows) dry matter disappearance

(%DM, w/w) of grass silage, whole crop silage, maize silage,

and lucerne hay from in sacco nylon bags incubated in the

cow rumen and recovered at time intervals to 72 h. Error bars

are standard error of means.

Figure 15. Neutral detergent fibre disappearance (%) of

whole crop silage, grass silage, maize silage, and lucerne

hay from in sacco nylon bags at time intervals to 72 h. Error

bars are standard error of means calculated from eight cows

per treatment.

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60 70 80

Dry

mat

ter

Dis

app

eara

nce

(%

)

in vivo Incubation (hours)

Whole crop silage

Grass silage

Maize silage

Lucerne hay

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60 70 80

ND

F D

isap

pea

ran

ce (

%)

in vivo Incubation (hours)

Whole crop silage

Grass silage

Maize silage

Lucerne hay




13.4 Mineral content and value of nutrients

Differences in the composition of minerals in the grain and stem fractions have consequences

for their use in animal feeding. Most minerals in whole-crop herbage occur in sub-optimal

concentrations for high-producing dairy animals. However, significant gains in N, P and Mg

concentrations can be made by raising the cutting height, thus increasing the proportion of grain

in the cut forage. In contrast, straw is valuable for its K and Ca content.

The overall concentration of minerals in mature WCS is characteristically low relative to the

requirements for high-producing dairy animals and when compared with high quality grass.

Barley has lower Ca and P concentrations but higher potassium than wheat, triticale or oats.

Triticales tend to be lower in S than other species, but higher in Mg. Requirements for

macronutrients by lactating animals are given in Table 19. The elemental concentrations of all

macronutrients in WCS were insufficient to support lactation at 2.0 kg milk solids /day. In

contrast, mineral concentrations in typical pasture are significantly higher (Table 19).

Table 19. Range of macronutrient (%) and trace elements (mg/kg dry matter (DM)) levels in whole crop

silage compared to pasture and the typical requirements to support high production (25 litre/day milk

or 2.0 kg milk solids (MS)/day.

Nutrients Cereal silageb

Typical pasture

Dairy cow requirement for 2.0 kg MS/daya Barley Wheat Triticale Oats

Macronutrients (%)

Phosphorus 0.06–0.10 0.15–0.21 0.16–0.18 0.19 0.35–0.45 0.3–0.35

Potassium 1.79–2.05 1.43–1.63 0.95–1.63 1.29 2.0–2.5 1.0 +

Calcium 0.23–0.25 0.30–0.36 0.30–0.33 0.34 0.4–0.6 0.6–0.8

Sulphur 0.13–0.17 0.17–0.19 0.12–0.15 0.19 0.27–0.32 0.23

Magnesium 0.069–0.093 0.069–0.098 0.095–0.109 0.145 0.015–0.25 0.22–0.28

Sodium -- -- -- -- 0.1–0.25 0.20

Trace elements (mg/kg DM)

Cobalt 0.04–0.07 0.07–0.15 0.11

Copper 4–6 8–12 12

Selenium 0.03–0.06 0.01–0.15 0.3

Zinc 18–25 25–45 40

a DairyNZ farm facts; b data from trial at Highbank, Canterbury.

Dietary cation anion difference (DCAD) for whole crop herbage was comparatively low for silage

harvested in all trials and therefore a potentially valuable complementary herbage to fresh

pasture that commonly is high in DCAD. Mean DCAD (me/kg) for barley, wheat, triticale and oat

were 122–177, 74–107, 28–72 and 83, respectively. Barley cultivars tend to have higher DCAD

than other cereals. WCS can be used to reduce milk fever an improve calcium nutrition in cows

during early lactation when silage is a significant component of the diet. WCS with a high grain

component can be used to specifically to enhance calcium mobilisation post-calving, therefore

reducing the requirement for calcium and magnesium supplements.




Specific care should be taken to feed supplement Ca and P to meet allowances for production

levels. In particular, there is some evidence to show that P nutrition is sub-optimal in animals

fed significant quantities of WCS. Add Mg and Na to balance pasture, especially when K levels

are high.

The grain component of WCS is important from the animal nutritional perspective and also

because the grain contributes a high proportion of the total herbage harvested. The grain

fraction contributes as much as 73% of the NN, 80% of the P, 63% of the Mg and 55% of the S.

As little as 36% of the K, 16% of the Ca and 11% of the Na occurs in grain.

If WCS comprises more than one-third of animal diet, it is necessary to calculate cow

requirements for protein. No additional protein is required in mixed pasture and supplement

diets when cereal silage contributes less than one-third of the diet and the rest is high quality

pasture.

14 Cost of production/margins for WCS and grain

crops

Key points:

Gross margin analysis for autumn wheat shows that it is equally profitable to produce

cereals for silage or grain (including baled straw)

In spring crops, the break-even whole crop yield for silage is around 8 t DM/ha.

Therefore significant profit can be gained with expected harvestable yield of 16 t/ha or

more.

14.1 Autumn wheat for silage or grain

Autumn- and winter-sown wheat crops can be used as either total biomass product or grain for

milling, feed or protein production. Traditionally, the crop is grown for the human food industry

and the residues following harvest are conserved for animal feed in bales. The grain is also

used for pig and poultry feeding, and to a lesser extent as a supplement for dairy cows. Grazing

of wheat at the green chop stage, or saving the crop for whole crop silage is increasing in

popularity, and driven by demands for off-paddock supplementary feeding, and concerns about

the high rate of N return in excreta while grazing in situ, with an accompanying increased risk of

soil nitrate accumulation and N leaching losses.

Gross margin analysis for autumn wheat shows that it is equally profitable to use the biomass

for feed or grain. The bulk residual after whole crop silage harvest can be as much as 3.0 t

DM/ha, which also contains a significant component of chaff and fine particle stem and leaf

material that is not recovered in the straw baling. This is incorporated into the soil in following

cultivation. The N composition of this residue and fine particle crop material returned to the soil

is low at around 0.5–0.9%N, meaning a recycling of 15–27.0 kg N/ha.

For ease of calculation, it is assumed that a similar bulk of residue was left after grain harvest

and straw baling compared with WCS removal. For the purpose of gross margin exercise, a

70% recovery of WCS biomass was assumed from total yield measurement from winter and




winter sown wheat for silage. The residue does contain some grain and leaf dropped during the

cutting and pick-up process. For a grain harvest, a crude estimate of harvest index of 50% grain

and 50% straw was assumed, with 70% of the total crop yield is taken off in grain + baled

herbage. Baled herbage was valued at 15 c/kg DM, compared with WCS at 25 c/kg and grain at

$275/t. The cultivars selected (‘Wakanui’ and ‘Morph’) were equally suitable for silage or grain.

The cost of growing the crops was the same irrespective of final use, i.e. grain + straw or whole

crop silage. Inputs (fixed costs) are summarised in Table 20.

Table 20. Base costs for winter wheat production with low and high fertiliser N rates.

Agronomic action Units Rate Cost/ha

Cultivation tractor and implement 3 hr 80 $/ha $ 240.00

Conventional drill – contract sowing 1 hr 80 $/ha $ 80.00

Seed Cultivar ‘Wakanui’ 134 kg/ha 1.11 $/kg $ 148.74

‘Morph’ 125 kg/ha 1.11 $/kg $ 138.75

Fertiliser Sulphate super

Sulphate super 200 kg 350 $/t $ 70.00

Spring basal

Urea 1 kg N/ha a 50 kg 690 $/t urea $ 75.00

Urea 2 kg N/ha a 50/100 kg 690 $/t urea $ 75/150

Urea 3 kg N/ha a 50/100 kg 690 $/t urea $ 75/150

Spreading 3 passes 25 $/ha/pass

$ 75.00

Growth regulator Moddus 0.25 L/ha 126.6

0 $/L $ 31.65

Cycocel 0.75 L/ha 9.21 $/L $ 6.91

Herbicide

Cougar 1 L/ha 66.6 $/L $ 66.60

Glean 15 g/ha 630 $/kg $ 9.45

Hussar 150 g/ha 161 $/g

$ 24.15

Fungicide

Proline 0.6 L/ha 96 $/L $ 57.60

Amistar 0.5 L/ha 100.8 $/L $ 50.40

Opus 3 L/ha 34.6 $/L $ 103.80

Insecticide Pirimor 200 g/ha 64.52 $/kg $ 12.90

Karate 120 mL/ha 684 $/L $ 82.08

Application (additional passes for chemicals) 7 passes 18 $/ha/pass

$ 126.00

Silage harvesting ha 400 $/ha $ 400.00

Grain harvesting ha 400 $/ha $ 400.00

Baling (straw) ha 300 $/ha $ 300.00

Irrigation water applied 115 mm 1.4 $/mm $ 161.00

a Low N = 50+50+50 kg N/ha; high N = 50+100+100 kg N/ha.

A fixed cost structure for 2013–14 autumn wheat trials, was used to determine the sensitivity of

profit covering a range of 8 to 20 t DM/ha for whole crop silage (Figure 16), or alternatively for a

combined grain plus the conserved baled residue. The profitability for grain plus baled straw is

given in Figure 17 for crop yields ranging from 7–22 t DM/ha.

Profitability of the WCS systems was slightly ahead of cereal for grain + baled residual. The

systems were compared with an assumed equivalent whole crop biomass. Grain and bales

required two biomass harvests meaning additional cost and potential additive losses. Both




silage and grain harvests were estimated at $400/ha. There was a difference in the calculation

for amount of residue returned to land. In the case of whole crop silage, the total biomass as

measured by quadrat harvest was reduced by 30% to account for potential field losses,

whereas the measured grain crop was assumed to fully recovered by mechanical harvest, but

the rate of recovery of the straw for baling was reduced by 30% (assuming a 50% harvest

index), and this accounted for the increased losses from chaff and fine material escaping baling.

The biomass return to the soil was a set proportion of the total silage crop biomass but was a

fixed proportion of the grain yield in the case of a grain + baled straw system. Break-even cost

was at 8 t/ha for silage (Figure 16A), 8 t/ha for grain alone (Figure 16 B), and 10 t/ha for

combine grain and baled straw (Figure 16C), with fixed costs of approximately $2000/ha for

silage and grain, with an additional $300/ha cost if straw from the grain crop is conserved as

bales (Figure 16C).

Profitability can also be defined as the average gross margin return per ha per day, i.e. adjusted

for the duration the crop is in the ground. High producing crops grown over a short period will

therefore be most profitable. This measure of production efficiency is increased by shortening

the number of days the crop is in the ground (i.e. sowing late or choosing cultivars that mature

earlier) but with equivalent yield.

Simulated break-even WCS yield was 8 t/ha for the high N input treatment, with profit in the

range of $2500–3000 /ha for a whole crop yield of 18 t/ha (Figure 17A and 17B). For equivalent

yield, the profitability was lowered because of the increases cost of applying N fertiliser.

However, the capacity of the crops to respond to N addition was dependent on whether the

crops were irrigated or not.

14.2 Spring wheat for silage or grain

Gross margin analyses for spring wheat crops were performed with equivalent protocols to the

autumn crops. Margins were again based on inputs and revenue (Table 21) for a trial in the

2013–14 season at Lincoln. Treatments comprised low, medium and high N fertiliser inputs for

irrigated and dryland crops. In these simulation not addition cost was allowed for except for

addition fertiliser cost for higher input systems.

Simulated break-even whole crop silage yield was 8 t/ha for the high N input treatment, with

profit in the range of $2500–3000/ha for a whole crop yield of 18 t/ha (Figure 17A and 7B). Profit

declined linearly with the reduction in yield. For equivalent yield, the profitability was lowered

because of the increases cost of applying N fertiliser. However, the capacity of the crops to

respond to N addition was dependent on whether the crops were irrigated or not.

These gross margins should only be used for comparing specific test treatments. Prices and

cost of inputs vary with time so the results may not be representative of other seasons. Input

costs and product prices should be updated if comparative margins are calculated for current

crop situations.




Table 21. Base costs for spring-sown wheat production with and without irrigation; and for low,

medium and high fertiliser N ratesa.

Agronomic action Units Rate Cost/ha

Cultivation tractor and implement 3 hr 80 $/ha $ 240.00

Conventional drill – contract sowing 1 hr 80 $/ha $ 80.00

Seed Cultivar ‘Wakanui’ 134 kg/ha 1.11 $/kg $ 148.74

Fertiliser CropZeal 16N (starter in drill pass)

24 kg N/ha 150 kg/ha 589

$/t $ 103.35

Spring basal

Urea 1 50/100 kg N/ha

a 690 $/t $ 75/150


a 690 $/t $ 75/150


a 690 $/t $ 75/150

Spreading 2 passes for low N

3 pass 25 $/ha/pass

$ 75.00

Herbicide

Cougar 1 L/ha 66.6 $/L $ 66.60

Glean 15 g/ha 630 $/kg $ 9.45

Hussar 150 g/ha 160 $/kg $ 24.15

Fungicide

Proline 1 0.2 L/ha 96 $/L $ 19.20

Proline 1 b 0.4 L/ha 96 $/L $ 38.40

Seguris Flexi c

0.6 L/ha 109.2

$/L $ 65.52

Insecticide Pirimor 200 g/ha 64.5

2 $/kg $ 12.90

Karate 1 40 mL/ha 684 $/L $ 27.36

Application (additional passes for chemicals) 5 d passes 18

$/ha/pass

$ 90.00

Silage harvesting 400 $/ha $ 400.00

Grain harvesting 400 $/ha $ 400.00

Baling (straw) 300 $/ha $ 300.00

Irrigation water applied

35/125 e mm 1.4 $/mm

$ 49/175

a Fertiliser costs are dependent on the rates and timing of N applied: Low N = 24 + 50 + 50 kg N/ha; Medium N = 24 + 100 + 50 + 50 kg

N/ha; High N = 24 + 100 + 100 + 100 kg N/ha. b, c not applied to low input crop; d 3 passes for low input and 4 passes for high input

crops; e 35 mm applied to dryland crop.




Figure 16. Sensitivity analysis for varying yield of whole

crop wheat silage (A), wheat alone (B), and wheat +

baled straw (C) given fixed production costs for winter

sowing and fertilised at low (50+50+50 kg N/ha) and

high (50+100+100 kg N/ha) N rates.

0

1000

2000

3000

4000

5000

4 6 8 10 12 14 16 18 20 22 24

Pro

fit

and

fix

ed c

ost

s ($

per

ha)

Whole Crop Silage Yield (t/ha)

Winter sowing, Low N


Fixed Cost, Low N

Fixed cost, High N

Expt data

A: Whole crop silage

-1000

0

1000

2000

3000

4000

5000

4 6 8 10 12 14 16 18 20 22 24

Pro

fit

and

fix

ed c

ost

s (

$ p

er h

a)

Grain Yield (t/ha)


Winter sowing, High N

Fixed costs, Low N

Fixed costs, High N

Expt data

B: Grain only

-1000

0

1000

2000

3000

4000

5000

4 6 8 10 12 14 16 18 20 22 24

Pro

fit

and

fix

ed c

ost

s (

$ p

er h

a)

Grain Yield + Straw Yield (t/ha)


Winter sowing, High N

Fixed costs, Low N

Fixed costs, High N

Expt data

C: Grain and baled straw




Figure 17. Sensitivity analysis for varying yield of irrigated whole

crop wheat silage (A) and dryland crop (B) with fixed production

costs for spring sowing with low (24+50+50 kg N/ha), medium

(24+100+50+50 kg N/ha) and high (24+100+100+100 kg N/ha) inputs

of N fertiliser (at sowing and in split applications during early crop

development). Irrigation water was applied at 35 mm for dryland (to

wash N fertiliser into soil), and 125 mm for the irrigated treatment).

-1000

0

1000

2000

3000

4000

5000

4 6 8 10 12 14 16 18 20 22 24

Pro

fit

and

fix

ed c

ost

s ($

per

ha)

Whole crop silage Yield (t/ha)

Spring sowing, low inputs Spring sowing, medium inputs Spring sowing, high Inputs Fixed costs, low inputs Fixed costs, medium inputs Fixed costs, high inputsExpt data 2013-14

A: Irrigated Whole crop silage

-1000

0

1000

2000

3000

4000

5000

4 6 8 10 12 14 16 18 20 22 24

Pro

fit

and

fix

ed c

ost

s ($

per

ha)

Whole crop silage Yield (t/ha)

Spring sowing, low inputs

Spring sowing, medium inputs

Spring sowing, high Inputs

Fixed costs, low inputs

Fixed costs, medium inputs

Fixed costs, high inputs

Expt data 2013-14

B: Dryland Whole crop silage




15 Summary

This report provides details of production and management of WCS as a supplementary feed.

Ideally, WCS is made from near-mature crops that are harvested as a standing crop at DM

content of 35–45%, or cut and wilted for a short period before chopping and ensiling. Cereals

harvested at booting stage (green chop) can also be made into good quality silage but must be

wilted to dry matter contents of 30–35%DM. Green chop silage has a higher protein content

than traditional WCS with equivalent energy value, but significantly reduced yield.

The flexibility of end use is a key feature of cereal forage. There are valid options for grazing a

vegetative crop, cutting at the mid-stem elongation stage for ‘green chop’ silage, saved for

whole crop silage at the mid dough stage, or harvested for grain (with the straw baled for use as

a high fibre roughage or bedding material). Advantages and disadvantages of forage and grain

options, the economic value, cost comparison and value of nutrients removed for each choice

are discussed. The place of WCS in cropping and pasture rotations, animal acceptability, gross

margins, versatility of use, and its potential as a catch crop for mopping N make whole crop

silage an attractive option for cropping farmers and graziers. Cultural practices for growing

whole crop silage are well established as there is little difference to the best management

practices developed for grain crops. Allowance must be made for withholding periods for

specific chemicals (herbicides, fungicides, insecticides and growth regulators) applied to the

crops, adhering to regulations set for product end use.

Integration of cereal crop silage into production systems can have benefits at a number of

levels. In addition to providing the specific feed requirements of the dairy, beef, and sheep or

deer industries, it is an economic short (spring-sown) or longer term (autumn-sown) crop that fit

well in rotations by following a winter grazed crop or used a cover during winter months. The

latter is a good ‘environmental’ option capturing N that is at risk of leaching in the spring. An

attractive rotation option is to produce cereal silage from paddocks leading into regrassing.

WCS suits the production patterns and feeding systems for both irrigated light land and heavy

soils. This is particularly the case for the dairying situation in the South Island where WCS

provides a low risk alternative to maize. Whole crop silage provides a good supply of energy

and fibre when there is a feed quality or quantity deficit between feed supply and feed demand,

or can be used to balance diets when fed with other supplements.

Maintaining high feed quality is important for developing a viable WCS industry. This can only

be achieved by good management of the growing crop, good silage preservation techniques

and efficient use of feed for energy requirements. Cereal silage made from near-mature crops

relies on the well-developed grain component to supply energy in the form of starch. It is

desirable to have a proportion of residual green leaf or green stem to raise the soluble

carbohydrate fraction. These are important substrates for rapid fermentation during the first few

days in the silage stack.

Farms equipped for cropping generally provide the most efficient platform for production.

However, the costs of transporting fresh herbage to sites for silage-making may alter the

economics of production.




16 References

Arnaudin ME, de Ruiter JM, Maley S, Pyke NB 2015. Managing whole crop cereal silage yield and

profitability of autumn-sown crops. Agronomy New Zealand 45: 26-37.

DairyNZ 2017. Facts and figures for New Zealand Dairy farmers 2nd Edition 163 p.

Dalley DE, Malcolm BJ, Chakwizira E, de Ruiter JM 2017. Range of quality characteristics of New Zealand

forages and implications for reducing the nitrogen leaching risk from grazing dairy cows. New Zealand

Journal of Agricultural Research (accepted)

de Ruiter JM, Arnaudin E. Maley S 2016. Performance and harvest timing of autumn-sown cereals for

silage: 2015-2016 trial results. A Plant & Food Research report prepared for: Foundation for Arable

Research. SPTS No. 13771, 34 pp.

de Ruiter JM, Dalley DE, Hughes TP, Fraser TJ, Dewhurst RJ 2007. Types of supplements: their nutritive

value and use Pp 97-115 in Pastures and Supplements for Grazing Animals. Rattray PV, Brookes IM, Nicol

AM. (ed.) New Zealand Society of Animal Production. Occasional Publication Number 14, Hamilton, New

Zealand.

de Ruiter JM, Zyskowski R, Cox G 2012. The cereal grain and silage calculator. PFR SPTS No. 6485, 31 pp.

de Ruiter J, Arnaudin E, Priergaard-Petersen H, Maley S, Pyke N 2013. Optimising harvest timing and

quality of a new awnless barley for silage. A report prepared for: Foundation for Arable Research. Plant &

Food Research: Contract No. 29964. Job code: P/411037/01. SPTS No. 8714.

de Ruiter JM, Maley S 2013. Effects of crop management on silage harvest timing for a new awnless barley

(cv Monty). Agronomy New Zealand 43, 41-54.

de Ruiter J, Gibbs J 2017. An assessment of metabolisable energy and quality of barley whole crop silage. A

Plant & Food Research report prepared for: AGMARDT and Foundation for Arable Research. Milestone No.

72249. Contract No. 34328. Job code: P/411210/01. SPTS No. 14616.

de Ruiter JM, Hanson R, Hay, AS, Armstrong KW, Harrison-Kirk RD 2002. Whole crop cereals for grazing

and silage: balancing quality and quantity. Proceedings of the New Zealand Grassland Association

Conference 64: 181-189.

Edwards GR, de Ruiter JM, Dalley DE, Pinxterhuis JB, Cameron KC, Bryant RH, Di HJ, Malcolm BJ,

Chapman DF 2014. Dry matter and body condition score change of dairy cows grazing fodder beet, kale and

kale-oat forage systems in winter. Proceedings of the New Zealand Grasslands Association 76: 81-88.

FAR 2002a. Whole-crop cereal silage option FAR Arable Extra No. 113, (http://www.far.org.nz). 2 p.

FAR 2002b, Nitrogen use for spring barley crops. FAR Arable Extra No. 117 (http://www.far.org.nz). 2 p.

FAR 2002c. Cultivars for whole-crop cereal silage FAR Arable Extra No. 114, (http://www.far.org.nz). 2 p.

FAR 2002d. PGRs on spring barley. FAR Arable Extra No. 122 (http://www.far.org.nz). 2 p.

FAR 2002e, FAR 2002d. Cutting times and quality of whole crop cereal silage FAR Arable Extra No. 124,

(http://www.far.org.nz). 2 p.

FAR 2003, Disease control in spring barley. FAR Arable Extra No. 139 (http://www.far.org.nz). 2 p.

FAR 2004. Changes in whole crop cereal silage at varied cutting times. FAR Arable Extra No. 140


FAR 2007. Spring sown barley disease control – susceptible variety FAR Arable Extra No. 188


FAR 2010. Disease control in cereals using new SDHI fungicides FAR Arable Update. 196





FAR 2011. Reducing Nitrous Oxide Emissions from Arable Farms. FAR Arable Update No 94,


FAR. 2013a. Nitrogen application in wheat and barley. FAR Cropping Strategies, Issue 4. Foundation for

Arable Research, Templeton. 9 p. https://www.dairynz.co.nz/feed/pasture-management/growing-

pasture/soil-fertility-for-pasture/

FAR 2013b. Crops for cows. FAR Focus Issue 10. (http://www.far.org.nz).

FAR 2015. Cereal growth stages ISBN: 978-0-9876673-9-7 27 p.

https://www.far.org.nz/assets/files/uploads/35448_FAR_ute_guide_-_cereal_growth_stages_(3).pdf

FAR 2016a. The role of silage inoculants. Arable Extra No. 121 4 p.

FAR 2016b. Crop Action Edition 142, 2 p.

FAR 2016c. Arable Update Issue 208. Harvesting whole crop silage, 2 p.

FAR 2018. FAR cropping strategies 5. Cereal disease management.

FAR 2019a. FAR Cultivar evaluation: Autumn sown wheat and barley 2018/2019.

FAR 2019b. FAR Cultivar evaluation: spring sown wheat and barley 2018/2019.

Grant CA, Moulin AP and Tremblay N 2016. Nitrogen management effects on spring wheat yield and protein

concentration vary with seeding date and slope position. Agronomy Journal 108: 1246-1256.

Grant CA, Wu F, Seles KN, Harker GW, Clayton GW, Bittman S, Zebarth BJ, Lupwayi NZ 2012. Crop yield

and nitrogen concentration with controlled release urea and split applications of nitrogen as compared to

non-coated urea at seeding. Field Crops Research 127: 170-180.

Horrocks A, Malcolm B, Scobie D, Edwards P, Pinxterhuis I, Beare M, Maley S, Teixeira E, Clement A,

McMillan N 2019. Guidelines for catch crops. https://www.far.org.nz/articles/1240/forages-for-reduced-

nitrate-leaching-guidelines-for-catch-crops

Malhi SS, Soon CA, Grant CA, Lemke R, Lupwayi N 2010. Influence of controlled-release urea on seed yield

and N concentration, and N use efficiency of small grain crops grown on Dark Gray Luvisols. Canadian

Journal of Soil Science 90: 363-372.

Milne GD. 2006. Cereal silage - a review of its use in the South Island. Proceedings of the New Zealand

Grasslands Association 68: 221-223.

MPI 2016. Feed Use in the NZ Dairy Industry: A review of feed volumes consumed by New Zealand dairy

cows since 1990-91, including future estimates to 2030-31.

NZFMRA 2009. New Zealand Fertiliser Manufacturers’ Research Association Managing Soil Fertility on

Cropping Farms. 64 pp. ISBN 978-0-9864528-3-3.

Rolston MP, Archie WJ, Reddy K, Dastgheib F 2003. Grass weed control and herbicide tolerance in cereals.

New Zealand Society of Plant Protection 56: 220-226.

Stevens DR, Platfoot GD, Hyslop MG, Knight TL, Corson, ID and Littlejohn RJ 2004. Dairy cow production

when supplemented with whole-crop cereal silages in spring and autumn. Proceedings of the New Zealand

Grassland Association 66: 75-82.

van Sanford DA, MacKown CT 1986. Variation in nitrogen use efficiency among soft red winter wheat

genotypes. Theoretical and Applied Genetics 72: 158-163.

Zadoks JV, Chang TT, Konzak CF 1974. A decimal code for the growth stages of cereals. Weed Research

14, 415-421.

https://www.dairynz.co.nz/feed/pasture-management/growing-pasture/soil-fertility-for-pasture/

https://www.dairynz.co.nz/feed/pasture-management/growing-pasture/soil-fertility-for-pasture/

https://www.far.org.nz/articles/1240/forages-for-reduced-nitrate-leaching-guidelines-for-catch-crops

https://www.far.org.nz/articles/1240/forages-for-reduced-nitrate-leaching-guidelines-for-catch-crops

http://www.plantandfood.co.nz




cereal silage crop management: current state of knowledge · [2] the new zealand institute for...

Documents