viii. wairarapa plains dryland, masterton

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This article was downloaded by: [Fondren Library, Rice University ] On: 02 December 2014, At: 16:18 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK New Zealand Journal of Experimental Agriculture Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tnzc19 VIII. Wairarapa plains dryland, Masterton G. Crouchley a b a Ministry of Agriculture and Fisheries , Masterton Field Research Area , R.D. 7, Masterton , New Zealand b Ministry of Agriculture and Fisheries , P. B., Hastings , New Zealand Published online: 30 Jan 2012. To cite this article: G. Crouchley (1979) VIII. Wairarapa plains dryland, Masterton, New Zealand Journal of Experimental Agriculture, 7:1, 31-33, DOI: 10.1080/03015521.1979.10426158 To link to this article: http://dx.doi.org/10.1080/03015521.1979.10426158 PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions

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Page 1: VIII. Wairarapa plains dryland, Masterton

This article was downloaded by: [Fondren Library, Rice University ]On: 02 December 2014, At: 16:18Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registeredoffice: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK

New Zealand Journal of ExperimentalAgriculturePublication details, including instructions for authors and subscriptioninformation:http://www.tandfonline.com/loi/tnzc19

VIII. Wairarapa plains dryland, MastertonG. Crouchley a ba Ministry of Agriculture and Fisheries , Masterton Field ResearchArea , R.D. 7, Masterton , New Zealandb Ministry of Agriculture and Fisheries , P. B., Hastings , New ZealandPublished online: 30 Jan 2012.

To cite this article: G. Crouchley (1979) VIII. Wairarapa plains dryland, Masterton, New Zealand Journalof Experimental Agriculture, 7:1, 31-33, DOI: 10.1080/03015521.1979.10426158

To link to this article: http://dx.doi.org/10.1080/03015521.1979.10426158

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all the information (the“Content”) contained in the publications on our platform. However, Taylor & Francis, ouragents, and our licensors make no representations or warranties whatsoever as to theaccuracy, completeness, or suitability for any purpose of the Content. Any opinions andviews expressed in this publication are the opinions and views of the authors, and are notthe views of or endorsed by Taylor & Francis. The accuracy of the Content should not berelied upon and should be independently verified with primary sources of information. Taylorand Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs,expenses, damages, and other liabilities whatsoever or howsoever caused arising directly orindirectly in connection with, in relation to or arising out of the use of the Content.

This article may be used for research, teaching, and private study purposes. Any substantialor systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply,or distribution in any form to anyone is expressly forbidden. Terms & Conditions of accessand use can be found at http://www.tandfonline.com/page/terms-and-conditions

Page 2: VIII. Wairarapa plains dryland, Masterton

N.z. Journal of Experimental Agriculture 7 (1979): 31-3 31

Nitrogen fixation in pasture VIII. Wairarapa plains dryland, Masterton

G. CROUCHLEY·

Masterton Field Research Area, Ministry of Agriculture and Fisheries, R.D. 7, Masterton, New Zealand

N fixation in pasture yielding 9.4 - 12.2 t DM/ha varied from 90 to 241 kg N/ha/annum over two consecutive years. Factors appearing to effect N fixation and clover growth included soil moisture deficits, clover root cyst nematode predation, and possibly clover flowering. There was a large growth response to a winter fertiliser N treatment over the f.-st 2 years of the trial, but no response in the third winter, after a season of exceptionally high N fixing activity.

INTRODUCTION The flat and rolling country of Wairarapa has

moderate limitations to pastoral and arable production because of its soils and climate. Frosts occur in sheltered places and mean temperatures range from 5-6°C (winter) to 17-18°C (summer). Because of a relatively low (900 mm) and very variable rainfall, often accompanied by strong winds, droughts, and dry spells occur, particularly from November to May. These result in a lowering of ryegrass and clover vigour in pasture and an ingress of browntop (Agrostis tenuis Sibth.). Farming in this area concentrates on fat lambs, some cereal cropping, and cattle finishing. Fodder crops are also grown for stock.

The trial reported here estimates pasture production and associated nitrogen fixation, in a stable pasture typical of those on the yellow-grey earths.

METHODS The trial at the Masterton Field Research Area ~as

on Kokotau silt loam, a moderately leached and strongly gleyed soil representative of the central yellow grey earths in southern parts of the North Island (N .Z. Soil Bureau 1968). Superphosphate at 250 kglha had been applied annually in early autumn for some years, and the site had been limed recently.

A core flock of 10 ewes was rotated round the ten 0.05-ha paddocks of the trial, the rotation being lengthened during winter and summer stress periods and shortened when pasture growth rates were high. Additional ewes were brought in to control surplus herbage.

Herbage production, botanical composition, N fixation, and soil moisture were estimated by the methods described by Ball et al. (1979). N fertiliser subplots (equivalent to 100 kg N/ha) were laid down

·Present address: Ministry of Agriculture and Fisheries, P.B., Hastings, New Zealand Received 10 August 1978.

in July and October, to measure responses to applied N.

RESULTS During 1974-75 the spring was very wet and the

summer very dry with the reverse pattern for the second year of the trial (Table 1). Soil moisture was near field capacity over winter with a severe dry spell throughout the summer in the first year, while in the second year soil moisture levels were more favourable for growth for most of the year (Fig. Id).

The peak daily pasture growth rate occurred in early November each' year with rather more production during the second year (Fig la, Ib, Table 2). The dominant pasture species were 'Grasslands Ariki' ryegrass (Lolium (multiflorum x perenne) x perenne) (to 50%), browntop (Agrostis tenuis Sibth.) (to 30%), 'Grasslands Apanui' cocksfoot (Dactylis glomerata L.) (to 7%). White clover (Trifolium repens L.) contributed 1-30% of production depending on the season. Crested dogstail (Cynosurus cristatus L.), goose grass (Bromus mollis L.), and annual clovers, at times with considerable quantities of dead material, made up the remainder of the herbage sampled. The pasture had been sown in 1970 with pedigree 'Grasslands Huia' white clover. At present white clover in the trial area shows about 50% true Huia type and 50% small-leaved types of non-pedigree origin (Williams & CorI).ege 1979).

Legume DM production increased during the second year' of the trial as did the annual total of N fixed. High N fixation rates occurred in November of both years, but in the second year a second and higher peak of activity occurred in February (Fig. lc).

When soils were near field capacity, over 85% of N fixation activity occurred in the top 75 mm of soil, but

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32 N.Z. Journal of Experimental Agriculture, Vol. 7, 1979

TABLE 1 - Total monthly rainfall, monthly mean screen air and 0.1 m soil temperatures for the experimental period

Rainfall (mm) 1974-75 1975-76 6 yr

July 161 121 122 Aug 142 89 91 Sept 144 24 70 Oct 131 43 83 Nov 17 95 66 Dec 30 42 59 Jan 72 100 54 Feb 36 95 46 Mar 38 45 55 Apr 43 39 70 May 116 45 99 June 138 120 100 Total!

mean 1068 858 915

TABLE 2 - Herbage DM and N yields (kglha) and N fixed (kg N/ha) over the 2-year experimental period at Masterton

Clover yield Grass yield Clover N yield Grass N yield N fixed

1974-75 1 229 8238

51 236 90 73

1975-76 2 175

10 041

N fixed/t clover DM

80 ~60 ~ !40

~20

98 352 241 111

O~--------------~~--+-~~~

2-0 (c) N-fixation

I -'=1-0 Z

• 1\ 1\ 1\ I \

" I \ I' I \ /. 'I, ~

~ 'J .... _/' ... 1\ .. \

\

Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun

Fig. 1. - Pasture system characteristics during 1974-75 (--) and 1975-76 (- - -)

(a) Pasture growth rates (b) Clover growth rates (c) N fixation rates (d) Soil moisture (% dry soil basis 0-75 mm depth).

2-0

1-0

Mean air temp. 0.1 m soil temp. 1974-75 1975-76 6 yr 1974-75 1975-76 6 yr

8.4 6.7 7.0 6.4 4.8 5.3 7.9 8.9 8.1 6.8 6.4 6.4

11.1 9.6 10.3 9.6 7.9 8.7 11.9 12.1 12.5 11.3 11.1 11.4 14.7 12.3 14.2 14.0 11.9 13.7 17.3 14.2 16.1 17.8 14.9 16.2 18.8 16.6 17.4 19.0 16.5 17.3 18.2 14.2 17.6 17.5 13.4 16.7 16.9 15.3 16.2 16.0 14.9 15.1 13.7 12.2 14.0 11.9 11.1 12.0 11.5 9.3 10.9 9.9 7.2 8.5 6.7 6.7 7.6 5.7 5.4 5.8

13.1 11.5 12.6 12.1 10.4 11.4

at each sampling depth there was usually some activity throughout the year. As soils dried out, fixation activity in the 0-75 mm layer varied considerably, but usually over 90% of the total N fixation activity still occurred in the top 150 mm of soil. During the summer of 1974-7 5, high fixation rates were measured in the 0-75 mm and 150-225 mm layers with very little activity in the 75-150 mm and 225-300 mm samples.

In 1974 and 1975, fertiliser N raised production by 285% and increased average growth rates from 15.1 to 43.0 kg DM/haJday over 8 weeks from the end of July. The October N application gave an average increase in DM production of only 60%. The July 1976 fertiliser plots showed no response to N when the average growth rate was 60 kg DM/haJday.

Analyses of water flow from tile drains under the experimental area showed 14 ppm NO.-N and 0.5 ppm NH.-N in the first flow of water in the late autumn. After this initial flow of water the NO.-N content dropped to less than 1 ppm and NH.-N to O.l ppm. Topsoil chemical characteristics were: total N 4500 kglha 0-150 mm; % N 0.271; C/N ratio 12.4; pH 5.6.

DISCUSSION Average pasture production measured by Lynch's

(1966) rate of growth method at the Masterton Field Research Area is 10 880 kg DM/ha. During the trial DM production was typical for the area. The difference in production between the two years, caused by contrasting rainfall and temperature patterns (Table 1), shows the uncertainty of pasture production in this region and the consequently variable responses to fertiliser N.

The rate of N fixation generally reflected soil moisture patterns, with variation throughout the year and a large difference between years. The onset of

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Crouchley: Nitrogen fixation in pasture VIII 33

clover flowering coincided with a decrease in N fixation rates. During the second summer, high fixation rates in January and early February were the result of exceptional rainfall in mid January, which allowed vigorous clover leaf growth for several weeks before the onset of flowering. In this region, therefore, soil moisture seems to be a critical factor governing clover growth, N fixation rates, and the depth of N fixing activity in the soil.

N fixation and clover growth rates declined in the spring of both years, probably through predation by clover root cyst nematodes (Heterodera trifolii Goffart) which are active in this season (Yeates 1973). Control of nematodes with fumigants at this time can give a 40% increase in production from pure Huia white clover plots (Yeates et al. 1974).

After the slightly below average pasture growth in the first year, there was a very significant lift in production from a late winter N application. This is in contrast to the second year when above-average pasture production and very high N fixing activity were recorded and there was no response to a late winter N application. Pasture growth rates during this period were four times higher than those previously recorded for control plots and also exceeded growth rates measured in N fertiliser plots for the previous

two winter applications. These results suggest that a substantial recharge of soil N may occur in some years, even though some N is lost through leaching.

Acknowledgments The author is grateful to T. K. Wyeth and R. Tomlinson

for assistance in the field and to the staff of DSIR, Grasslands Division for laboratory services, herbage dissection, and soil analyses.

REFERENCES Ball, Roger; Brougham, R. W.; Brock, 1. L. ; Crush, J. R.;

Hoglund,1. H.; Carran, R. A. 1979: Nitrogen fixation in pasture I. Introduction and general methods. N.z. Journal of Experimental Agriculture 7: 1-5.

Lynch, P. B. 1966: Conduct of field experiments. N.Z. Department of Agriculture, Bulletin No. 399.

New Zealand Soil Bureau 1968: Soils of New Zealand Part 1. N.Z. Soil Bureau Bulletin 26 (1).

Yeates, G. W. 1973: Annual cycle of root nematodes on white clover in pastures. N.Z. Journal of Agricultural Research 16: 569-74.

Yeates, G. W.; Crouchley, G.; Whitehall, 1. T. 1974: Effect of soil fumigation on white clover growth in a yellow­grey earth infected with clover cyst nematode. Ibid. 18: 149-53.

Williams, W. M.; Comege, E. 1979: Nitrogen fixation in pasture Xl. White clover populations at nine sites in New Zealand. N.Z. Journal of Experimental Agriculture 7: 43-4 ..

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