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Nitrogen turnover and leaching in cropping systems with ryegrass catch crops

Aronsson, Helena (2000). Nitrogen turnover and leaching in cropping systems with ryegrass catch crops. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae. Agraria, 1401-6249 ; 214
ISBN 91-576-5739-4
[Doctoral thesis]

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This thesis deals with perennial ryegrass (Lolium perenne L.) catch crops and their short- and long-term effects on nitrogen leaching and nitrogen turnover in soils. Results are presented from three field experiments on a sandy soil in south-west Sweden, where undersown catch crops were used in cropping systems with and without applications of liquid manure. The effects of different tillage practices on soil mineral nitrogen and leaching were also studied. Two coupled simulation models, which describe water flow and nitrogen transformations and transport in soil, were used for calculations of nitrogen mineralization and soil nitrogen balances. A more detailed study of the residual effects of ryegrass on the nitrogen supyly to the subsequent crops and nitrogen leaching was performed in lysimeters, using 'N-labelled ryegrass. Undersown catch crops efficiently reduced nitrogen losses when mineral fertilizer or manure was applied at normal rates (90-1 10 kg Nha). Over five years, undersown catch crops reduced nitrogen leaching by 60%, on average, compared with soil which was conventionally tilled in August-September. Incorporation of catch crops affected nitrogen mineralization mainly during the first growing season following incorporation, when approximately 20-30% of catch crop nitrogen was released. The results emphasize the importance of an early onset of nitrogen mineralization in spring after incorporation of catch crops. This is necessary in order to overcome the soil-depletion effect of nitrogen uptake induced by the catch crop. Simulations showed that incorporation of catch crop material in late autumn instead of spring can result in a time distribution of nitrogen mineralization more suitable for a subsequent cereal crop, but this was not verified by the results of the lysimeter experiment. It seems important to obtain further knowledge of how to improve the degree of synchronization between nitrogen mineralization after incorporation of catch crops and nitrogen demand of the subsequent crops. According to simulations, the main part of the catch crop nitrogen contributed to a long-term accumulation of soil organic nitrogen (+I0 kg N per hectare and year), while it slowly declined in autumn-tilled soil given mineral fertilizer (-30 kg N per hectare and year). However, the accumulation of soil organic nitrogen due to the catch crops was very modest compared with the total amount of organic nitrogen in the soil.

Authors/Creators:Aronsson, Helena
Title:Nitrogen turnover and leaching in cropping systems with ryegrass catch crops
Series Name/Journal:Acta Universitatis Agriculturae Sueciae. Agraria
Year of publishing :January 2000
Number of Pages:32
ALLI. Aronsson, H. & Torstensson, G. 1998. Measured and simulated availability and leaching of nitrogen associated with frequent use of catch crops. Soil Use and Management, 14,6- 13. II. Stenberg, M., Aronsson, H., Lindén, B., Rydberg, T. & Gustafson, A. 1999. Soil mineral nitrogen and nitrate leaching losses in soil tillage systems combined with a catch crop. Soil & Tillage Research, 50, 115-125. III. Torstensson, G. & Aronsson, H. 2000. Nitrogen leaching and crop availability in manured catch crop systems in Sweden. Nutrient Cycling in Agroecosystems (in press). IV. Aronsson, H. 2000. Contribution of "N-labelled ryegrass nitrogen to crop uptake and leaching after autumn or spring incorporation in lysimeters. (Submitted to Plant and Soil).
Place of Publication:Uppsala
ISBN for printed version:91-576-5739-4
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:T Pollution > T01 Pollution
Subjects:Not in use, please see Agris categories
Agrovoc terms:lolium perenne, catch crops, cropping systems, leaching, mineralization, nitrogen cycle, liquid manures, fertilizer application, water pollution, tillage, time, sweden
Keywords:catch crop, perennial ryegrass, nitrogen leaching, nitrogen mineralization, liquid manure, time of tillage, long-term effect, nitrogen balance
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ID Code:6
Department:(NL, NJ) > Dept. of Soil Sciences (until 081001)
Deposited By: Staff Epsilon
Deposited On:22 Apr 2002 00:00
Metadata Last Modified:02 Dec 2014 10:01

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