Allelopathy weeds inhibition species of cover in corn cropping

Abstract

Allelopathy is important for weed control and to reduce production costs and risks of human and environment contamination by herbicides. The following effects were investigated on Digitaria spp and Bidens sp. a) different extract concentrations of shoots, whole plants and roots of cover crops b) straw levels of cover crops, incorporated or not into the soil c) allelopathic effect of cover crops on the suppression of weeds in corn cropping. In laboratory, extracts of Raphanus sativus and aerial plant parts, in the higher concentrations, are the main source of allelochemicals to control Digitaria spp. and Bidens sp. In greenhouse, Lolium multiflorum straw causes greeter reduction in growth of Digitaria spp., where as for Bidens sp., R. sativus or Brassica napus straw show higher reduction. Straw on soil surface decreases Digitaria spp. and Bidens sp. growth. In field conditions the highest control of weed and growth of corn crop was observed for dessecated L. multiflorum with glyphosate and paraquat. The management of cover crops on the productivity of grains, depends on the used species. Application of nicosulfuron increased corn yield, independently of crop or management.