Effect of annually repeated undersowing on cereal grain yields

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.

Meta-analysis of the effects of undersown catch crops on nitrogen leaching loss and grain yields in the Nordic countries

“…However, a disadvantage of undersowing catch crops is competition with the main crops for nutrients, soil moisture and light, resulting in a few-percent loss of grain yield (Jensen, 1991;Andersen and Olsen, 1993;Breland, 1996;Lyngstad and Børresen, 1996;Karlsson-Strese et al, 1998;Känkänen et al, 2001Känkänen et al, , 2003 or a statistically non-significant reduction of yield (Wallgren and Lindén, 1994;Ohlander et al, 1996).…”

Soil nitrate N as influenced by annually undersown cover crops in spring cereals

“…Time: 1 = in March before soil thawing, 2 = in May before sowing, 3 = between September 13 and 25 after cereal harvest, 4 = in October before autumn ploughing and 5 = in November near soil frosting. Känkänen, stantially due to westerwold ryegrass (Känkänen et al 2001). Drainage runoff and nitrate N leaching in Finland are normally highest in November, December and April (unpublished data from two leaching experiment fields at MTT).…”

“…Information on weather conditions during the experimental years is given in detail by Känkänen et al (2001). Vol.…”

“…During last four years, soil NO 3 -N content was measured on different dates in order to determine timing of N mineralisation. Moreover, as N fertilization decreased the yield of clovers and increased the yield of westerwold ryegrass (Känkänen et al 2001), also effects on soil N was expected, and therefore soil NO 3 -N content under different N fertilizer regimes was examined, too.…”

“…Grain yields in this study have been published in an earlier paper (Känkänen et al 2001). Annual undersowing with clovers increased, and undersowing with westerwold ryegrass decreased cereal grain yields.…”