Mechanical control of clover improves nitrogen supply and growth of wheat in winter wheat/white clover intercropping

M. D. Thorsted^1,2, J. E. Olesen² and J. Weiner¹

Abstract
The major objective for clover in a winter wheat/white clover intercropping system is to supply nitrogen (N) for the wheat.

A field experiment was repeated in 2 years on a loamy sand in Denmark to investigate the possibilities for increasing N supply to the winter wheat by cutting and mulching the clover between the wheat rows.

The clover was cut with a weed brusher on three different dates in each year.

Intercropped wheat with unbrushed clover had a lower grain yield than wheat as a sole crop. Brushing increased wheat N uptake and wheat grain yields. Intercropping with two or three brushing dates gave higher wheat yields than wheat as the sole crop.

The largest increases in grain N uptake, 21–25 kgNha-1, were obtained for the brushings around wheat flag leaf emergence. The highest yield increases with a single brushing, 0.98–1.11MgDMha-1, were obtained when brushing was performed during the stem elongation phase. The largest grain yields for treatments with two brushings were obtained with a first brushing at start of stem elongation and a second around flag leaf emergence.

The first brushing probably provided N to increase the wheat leaf area index and thus the light interception, while the second brushing provided N to sustain the leaf area during grain filling and reduced clover biomass and therefore competition for water. Intercropping wheat and clover increased grain N concentrations by 0.11–0.39%-point compared with wheat as a sole crop.

Intercropping may thus offer possibilities for improving the bread-making quality of organically grown wheat.

Source
European Journal of Agronomy 24 (2006) 149–155

Author Locations and Affiliations
(1) Department of Ecology, Royal Veterinary and Agricultural University, DK-1958 Frederiksberg, Denmark
(2) Department of Agroecology, Danish Institute of Agricultural Sciences, P.O. Box 50, DK-8830 Tjele, Denmark

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Research Extension Courses Consumers -------------------------- Virtual Tours Student & Job Opportunities News Articles Standards -------------------------- Market Information Events Issues Animal Welfare Strategic Plans -------------------------- Links Award-winners Site Map	Mechanical control of clover improves nitrogen supply and growth of wheat in winter wheat/white clover intercropping M. D. Thorsted^1,2, J. E. Olesen² and J. Weiner¹ Abstract The major objective for clover in a winter wheat/white clover intercropping system is to supply nitrogen (N) for the wheat. A field experiment was repeated in 2 years on a loamy sand in Denmark to investigate the possibilities for increasing N supply to the winter wheat by cutting and mulching the clover between the wheat rows. The clover was cut with a weed brusher on three different dates in each year. Intercropped wheat with unbrushed clover had a lower grain yield than wheat as a sole crop. Brushing increased wheat N uptake and wheat grain yields. Intercropping with two or three brushing dates gave higher wheat yields than wheat as the sole crop. The largest increases in grain N uptake, 21–25 kgNha-1, were obtained for the brushings around wheat flag leaf emergence. The highest yield increases with a single brushing, 0.98–1.11MgDMha-1, were obtained when brushing was performed during the stem elongation phase. The largest grain yields for treatments with two brushings were obtained with a first brushing at start of stem elongation and a second around flag leaf emergence. The first brushing probably provided N to increase the wheat leaf area index and thus the light interception, while the second brushing provided N to sustain the leaf area during grain filling and reduced clover biomass and therefore competition for water. Intercropping wheat and clover increased grain N concentrations by 0.11–0.39%-point compared with wheat as a sole crop. Intercropping may thus offer possibilities for improving the bread-making quality of organically grown wheat. *Source* European Journal of Agronomy 24 (2006) 149–155 *Author Locations and Affiliations* (1) Department of Ecology, Royal Veterinary and Agricultural University, DK-1958 Frederiksberg, Denmark (2) Department of Agroecology, Danish Institute of Agricultural Sciences, P.O. Box 50, DK-8830 Tjele, Denmark en français
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Mechanical control of clover improves nitrogen supply and growth of wheat in winter wheat/white clover intercropping

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