Cover crop effects on soil structure and early sugar beet growth

Abstract

AbstractCover crops can improve soil properties, especially soil structure, through organic matter input and rooting activity. However, large variations exist among cover crops, which may lead to differences in the extent of these effects. In this study, cover crops with differing properties were compared regarding soil structure and subsequent sugar beet growth. Field experiments were conducted at two Luvisol sites in Central Germany. Four cover crops (oil radish, saia oat, spring vetch and winter rye) were compared with fallow. Cover crop effects on soil water, Nmin content, soil structure and subsequent early sugar beet growth were studied. Additionally, sugar beet received either no or optimal N fertilizer application. Rye and radish had the highest and vetch the lowest above‐ and belowground biomass. Soil water content was hardly affected by cover cropping, while topsoil Nmin contents in April were increased. Penetration resistance was lowered, and aggregate stability was increased by the cover crops, especially oil radish, while values after spring vetch were similar to those of fallow. Differences among the cover crops might be because of a differing root biomass. Independent of N fertilizer application, sugar beet biomass in May tended to be higher after all cover crops, in particular under oil radish. The higher aggregate stability and lower penetration resistance were found to be beneficial for early sugar beet growth. Thus, sugar beet can benefit from a 1‐year cultivation of preceding cover crops. Modifications of this effect through cover crop root biomass and architecture as well as repeated cover cropping need to be investigated in further studies.