Systematic design and evaluation of crop rotations enhancing soil conservation, soil fertility and farm income

FACULTAD DE AGRONOMIA

Dr. Santiago DogliottiAttached Professor Plant Production Department

FACULTY OF AGRONOMY – UNIVERSITY OF THE REPUBLICURUGUAY

Layout of the lecture

� Introduction

� Impact of crop rotation on crop yields and soil fertility

� Design criteria

� Design tools

� Prototyping

� ROTAT

� Farm Steps

� Evaluation criteria and evaluation tools

“A crop rotation is a sequence of crops grown in succession on a particular field”

Block 1b

Block 5b

Block 2b Block 3b Block 4b Block 6b Block 7b

Bl 2a Bl 2a

Bl 1a

Bl 4a

Bl 4a Bl 4a

Bl 3a Bl 5a

Bl 6a

Rotation effects on farm systems results

� Physical, chemical and biological soil fertility

� Crop yields

� Labor and inputs requirements = production costs

� Temporal distribution of the demand of labor and other resources, and cash flow

Rotation effect on potato yield (Scholte, 1989)

RotationPotato yield

(g/m2)

% of stems infested with V. daheliae

Potato monocropping

99 c 49 a

Maize - Potato 131 b 39 b

Sugar beet - Potato 118 bc 50 a

Maize - Sugar beet - Barley - Barley -

Potato152 a 21 c

Rotation effect on wheat yield (Berzsenyi et al., 2000)

0

1

2

3

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5

6

monocultivo 2 trigo - 2 maíz 5 trigo - 3 alfalfa 2 trigo - 3alfalfa - 3 maíz

trigo - maíz -cebada - arveja

Ren

dim

ient

o (t

ha-1

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WheatY

ield(M

g/ha)

Monocropping 2 Wheat-2 Maize 5 Wheat-3 Alfalfa 2 Wheat-3 Alfalfa Wheat - Maize-3 Maize Barley - Peas

Effect of crop rotation on weeds population (Covarelli y Tei, 1988)

with weeding

without weeding

Maize monocropping

24500 55800 422

Maize - Wheat 18920 19300 161

Number of weed seeds per m2

RotationNumber of

weeds per m2

Effect of crop rotation and cover crops onsoil erosion and soil organic matterbalance

RotationEstimated

Erosion (Mg/ ha yr)

Soil Organic Matter balance

(kg/ ha yr)

Estimated Erosion

(Mg/ ha yr)

Soil Organic Matter balance

(kg/ ha yr)

4 years Grass&Clover pasture - Onion - Sweet Potato - Sweet Maize - Onion (8 years rotation)

6.8 + 22 6 + 71

4 years Grass&Clover pasture - Onion - Sweet Potato - Sweet Pepper - Onion (8 years rotation)

9.0 + 8 6.5 + 61

Onion - Autumn Potato - Sweet Maize - Sweet Potato - Sweet Maize (4 years rotation)

13.5 - 152 7.6 - 8

Onion - Sweet Potato - Sweet Pepper - Sweet Maize (4 years rotation)

15.5 - 173 11.6 - 24

Traditional soil management Including Cover Crops

Soil erosion estimated using RUSLE (Renard et al., 1997) and Soil Organic Matter balance estimated using ROTSOM (Dogliotti et al., 2004)

Effects of cover crops as inter-crop

activity in crop rotations(Scholberg et al., in press)

Process

Cover crops

Canopy functions

Root functions

Soil cover

Primary effects

Biomass production

Nutrient storage

Soil/nutrient retention

Root symbiosis

Root growth & exudates

Ecological functions

Secondary effects

• Food, fuel, forage (+)• Soil amendment (+)• Mulch layer (+)

• Crop production (+) • Nutrient leaching (-)• Resource depletion (-)

• SOM (+)• Carbon sequestration (+)• Production costs (+/-)

• Weed suppression (+)• Wind/water erosion (-)• Runoff (-)• Soil temperature (-)• Soil moisture (+)

• Soil nutrient supply (+)

• SOM (+)• Crop water use effic. (+) • Crop production (+)• Sediment losses (-)• Nutrient leaching (-)

• Biodiversity (+)• Habitat (+) • Pest dispersal (-)

• Beneficials (+)• Pests (-/+)• Crop production (+/-)

• Wind/water erosion (-)• Nutrient retention(+)

• SOM (+) • Crop production (+) • Environm. impacts (-)

• Water infiltration (+)• Water retention (+)• Soil compaction (-) • Runoff (-) • Nutrient availability (+)• Weed suppression (+)

• Nitrogen fixation (+) • Mycorrhizal symbiosis(+)

• SOM (+)• Crop production (+)• Flooding (-)• Groundwater recharge (+)• Environm. impacts (-)

• Nutrient imbalance (-)• SOM (+)• Crop production (+)

Designing a crop rotation

Which are the main characteristics that define a crop rotation?� Crop species and families

� Frequency of each crop and crop family

� Sequences of crops

� Rotation length (time to complete a cycle)

Designing a crop rotation

1. Selection of crops• Profitability, market, constraints related to

farm resource availability

• Soil quality, water demand and climate requirements of crops

• Ensure variability in:� Botanical families

� Harvested organ

� Soil cover

� Residue/yield ratio

� Growth period

2. Crop sequences (Vereijken et al., 1997)� Never schedule successions of the same species

or the same family or crops sensitive to a soil borne disease relevant in the region.

� After a crop with a negative effect on soil fertility schedule a crop with positive effect: soil cover, rooting system, organic resiudes, harvested organ, N left.

� Take into account harvest and sowing periods of each crop including enough time for appropriate soil tillage.

Designing a crop rotation

3. Crop frequency

Estimated effect of crop frequency in the rotation on yield reduction from maximum yield (Molendijk y Mulder 1996).

Designing a crop rotation

1:2 1:3 1:4 1:5 1:6 1:7

Potato Globodera 0.25 0.5 0.75 0.9 1 1

Verticillum 0.85 0.9 0.94 0.97 1 1

Rhizotocnia 0.9 0.93 0.95 0.98 1 1

Rhizomanie 0.9 0.92 0.93 0.94 0.95 1

Onion and Ditylenchus 0.5 0.75 0.85 0.9 1 1Garlic Scl. Cepivorum 0.5 0.6 0.65 0.7 0.75 1

Fusarium 0.2 0.4 0.6 0.7 0.75 1

Maize Ditylenchus 0.75 0.9 1 1 1 1Wheat 0.75 0.9 1 1 1 1

Frequency in the rotationCrop Diseases

Designing a crop rotation4. Rotation Length or duration (years)

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Block 5b

Block 2b Block 3b Block 4b Block 6b Block 7b

Bl 2a Bl 2a

Bl 1a

Bl 4a

Bl 4a Bl 4a

Bl 3a Bl 5a

Bl 6a

RotationLength

(yr)

IrrigatedBeans Leek

WCCTable

tomatoWCC

Sm Squash

WCCSw

MaizeLeek

Ind Tomato

WCCSw

MaizeWCC 6

Rainfed Onion WCC Squash WCC Maize 74 years Grass clover pasture

Inter-crop activities : Aims

� Reduce soil erosion

� Increase soil organic matter content

� Reduce nutrient losses

� Improve soil structure

� Reduce weed seed bank

� Reduce the incidence of soil borne diseases

Tools to aid crop rotation design

� Prototyping (Vereijken et al, 1997)

� ROTAT

� FarmSTEPS

Evaluation of a crop rotation in prototyping approach (After Vereijken et al., 1997)

Crop cover:No cover in autumn or winter = 0No cover in spring or summer = 1Partial cover in autumn or winter = 2Partial cover in spring or summer = 3Good cover = 4Very good cover = 5

Organic matter input:<1000 kg MS/año = 01000-2000 kg MS/año = 12000-3000 kg MS/año = 22000-3000 kg MS/año = 33000-4000 kg MS/año = 4>4000 kg MS/año = 5

Crop Soil coverCompactation due to tillage and harvest

Effect of roots on

soil structure

Organic Matter in residues

Letuce 0 2 0 0Cabbage,

Cawliflower2 2 1 0

Peas 1 2 0 0Carrots 2 a 3 0 0 0Onion 0 1 0 0Garlic 0 1 0 0Potato 2 a 3 0 0 0

Tomato (table) 2 2 1 0Tomato (industry) 3 2 1 1

Sweet pepper 2 2 1 1Sweet potato 4 0 1 1

Squash 3 2 1 1Water melon 2 2 1 0Sweet maize 3 2 2 2

Wheat 4 3 4 2Winter green

manure4 3 4 4

Summer green manure

3 3 4 4

G&L pasture 5 4 4 5

Effects on soil fertility

ROTAT♦Crop list♦Rules and filters

ROTYIELD

Potential Crop Yields

Crop Growth Simulation models or experimental yields

Yield Reduction

Factors

♦ Cropping frequency (single crop, groups of crops)

♦ Inter-crop management and crop-crop successions

♦ Production techniques such as: irrigation, crop protection, mechanization

Production Activities filesClassified by soil type and management type with the yield of each crop in the rotation

DATABASE

Quantification Field level

RUSLE for crop rotationsROTEROSION

Long-term fate of soil organic matter

ROTSOM

N – P – K balance

EEP - calculator

Fodder calculator: energy, protein and qm

Labor distribution calculator: half month periods

Data handling program

SmartFarmerFarming systems

design program (MILP)

Farm Scale

Gross and Net margin, capital requirements at field level

Water balance at crop or crop rotation level

Software to aid design and evaluation ofrotations, explorative approach (Dogliotti, 2003)

Design and evaluation results

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Gross margin, soil erosion, N surplus, EEP-soil and rate of change of SOM as a function of the labour requirement per ha of productionactivities designed for high mechanisation level (Dogliotti et al., 2004)

The Farm STEPS approach

1. The crop plan: Based on the current crop and animal activities of the farm and only few new activities, it optimizes family income subject to constraints related to resource availability and agronomic rules

2. The cropping plan: Based on the history and eligibility of each field, the crop plan and agronomic rules, it allocates crop sequences to fields to produce a land use plan for the next few years.

3. Ex-ante evaluation of the plan: Based on technical coefficients and semi-quantitative indicators it evaluates the economic and environmental results of the cropping plan