Advancing cover cropping in temperate integrated weed management.

Abstract

\n The effects of cover crops on weeds and the underlying mechanisms of competition, physical control and allelopathy are not fully understood. Present knowledge obtained reveals a great potential for using cover crops as preventive method in integrated weed management. Cover crops are able to suppress 70 - 95 % of weeds and volunteer crops in the fall-to-spring period between two main crops. Cover crop residues can additionally reduce weed emergence in the early development of the following cash crop presenting a physical barrier and releasing allelopathic compounds in the soil solution. Therefore, cover crops can partly replace the weed suppressive function of stubble-tillage operations and non-selective chemical weed control in the fall-to-spring season. This review describes methods to quantify competitive and allelopathic effects of cover crops. Insight obtained through such analysis is useful for mixing competitive and allelophathic cover crop species with maximal total weed suppression ability. It seems that cover crops produce and release more allelochemicals when plants were exposed to stress or physical damage. Avena strigosa for instance, showed a stronger weed suppression under dry conditions than during a moist autumn. These findings raise the question if allelopathy can be artificially induced. This article is protected by copyright. All rights reserved.\n