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

Abstract

Cover crops can reduce leaching and erosion, introduce variability into crop rotations and fix nitrogen (N) for use by the main crops. In Finland, undersowing is a suitable method for establishing cover crops in cereals. The effect of annual undersowing on soil nitrate N 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 during six successive seasons, and a pure stand of cereal was grown in two years after that. In all years, the soil nitrate N was measured in late autumn, and in addition in different times of the season in last four years. The effect of undersowing on soil NO3-N content was generally low, but in one season when conditions favoured high N leaching, westerwold ryegrass decreased soil NO3-N. The negligible increase of N leaching risk in connection with undersowing clovers, associated with late autumn ploughing, supports the use of clovers to increase the cereal grain yield. The highest levels of soil NO3-N were recorded at sowing in spring irrespective of whether a crop was undersown or not. NO3-N contents were higher in sandy soil than in silt. Undersowing can be done annually in cereal cultivation either to fix or catch N. No cumulative effects on soil nitrate N were associated with undersowing after six years.;

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).…”

Cover Crop Effects on Corn Plant Sap Flow Rates and Soil Water Dynamics

“…The types of CC used and the planting and termination times could also affect the grain yield. Studies have emphasized mixed results of CC use on grain yield, reporting reduced grain yields with spring-sown CC due to high competition with primary crop for resources (Känkänen et al, 2003), no effects on grain yield (Ohlander et al, 1996), and reduced yields by monocropped CC and increased yields by legume and nonlegume CC mixtures (Abdalla et al, 2019).…”

The effect of interspecies interactions and water deficit on spring barley and red clover biomass accumulation at successive growth stages

“…The use of atmospheric N can also be considered as a form of niche differentiation (complementarity) [19]. The undersowing of legumes delivers positive effects by increasing N 2 fixation and making nitrogen available for cereals [37,39].…”