Effect of annually repeated undersowing on cereal grain yields

H Känkänen,C Eriksson,M Räkköläinen

doi:10.23986/afsci.5693

Abstract

Cover crops can be used to reduce leaching and erosion, introduce variability into crop rotation and fix nitrogen (N) for use by the main crops. In Finland, undersowing is a suitable method for establishing cover crops in cereal cropping. The effect of annual undersowing on cereal grain yield and soil mineral N content in spring was studied at two sites. Red clover (Trifolium pratense L.), white clover (Trifolium repens L.), a mixture of red clover and meadow fescue (Festuca pratensis Huds.), and westerwold ryegrass (Lolium multiflorum Lam. var. westerwoldicum) were undersown in spring cereals in the same plots in six successive seasons, and their effects on cereal yield were estimated. Annual undersowing with clovers increased, and undersowing with westerwold ryegrass decreased cereal grain yields. The grain yield was only slightly lower with a mixture of red clover and meadow fescue than with red clover alone. Westerwold ryegrass did not affect soil mineral N content in spring and the increase attributable to clovers was small. The mixture of red clover and meadow fescue affected similarly to pure red clover. Soil fertility was not notably improved during six years of undersowing according to grain yield two years later.

Highlights

Introduction tumn and winterLegumes can fix nitrogen (N)to the benefit of other crops in the rotation
In 1993 at Laukaa the N yields were only 3–5 kg ha–1 before autumn ploughing, when high rates of N fertiliser application were used on red clover, white clover and R.C. & M.F., and when low N fertilisation was used on westerwold ryegrass
The results suggest that annually repeated undersowing with nitrogen-fixing clovers is increasing cereal grain yields, because the positive residual effect is greater than the negative competition effect caused by clovers

Summary

Introduction

Introduction tumn and winterLegumes can fix nitrogen (N)to the benefit of other crops in the rotation. Growing cover crops after harvesting the main crop can reduce leaching and erosion during au-. H. et al Effect of annual undersowing on cereal grain yields. In addition to the competitive effect on the main crop, an undersown crop can affect the growth of the subsequent crop (Brandt et al.1989). These two effects of undersowing have usually been studied separately, whereas the combined effect of annual undersowing has been studied less. Because of the obvious sensitivity of undersown crops to the weather (Nilsdotter-Linde et al 1995), long-term experiments are needed to allow a more accurate understanding of the effects of undersowing

Objectives

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Discussion

Conclusion