Perennial Clovers and Ryegrasses as Understorey Crops in Cereals

Bergkvist, G. 2003. Perennial clovers and ryegrasses as understorey crops in cereals. Doctor’s dissertation. ISSN 1401-6249, ISBN 91-576-6439-0 Perennial crops undersown in cereals provide ground cover from harvest of the cereal crop to sowing of the next crop. Such cover crops can e.g. reduce soil erosion, nutrient leaching and N fertiliser requirements of the succeeding crop. The objective of this thesis was to develop guidelines on how to prevent grain yield losses due to competition from the perennial crops or to increase the yield of the main crops. The effects of species and time of undersowing of perennial crops in spring cereals, and the management of an intercropping system in which winter oilseed rape or consecutive crops of winter wheat were established in a remaining crop of white clover, were studied. The biomass of undersown cover crops by the time of the harvest of spring barley was significantly reduced with each delay in the undersowing, but the