Allelopathic interference of Sonchus oleraceus L. with wheat and the associated weeds: a field study

A field study was conducted to examine the allelopathic potential of Sonchus oleraceus L. residue against the weeds associated with wheat crop. Residue application was carried out under field conditions in two doses: 150 and 300 g m−2. Weed richness, density and above-ground biomass were assessed at 6 and 12 weeks after application to evaluate the potential effect of S. oleaceus manure on weed control. Some growth criteria and the total yield of the cultivated wheat crop were also measured. The residue-containing quadrates attained lower weed richness, density and biomass. Unlikely, residue application reduced the grain yield of wheat. The available nitrogen and phosphorus were increased in soil at the higher application dose. These results suggest that S. oleraceus could interfere most of winter weeds, but affect productivity of wheat. Weed suppression could be attributed to the allelopathic potential of S. oleraceus residue. These results suggest also that the manure of this weed could be used successfully in the integrated weed management programs to reduce weed infestation in winter crops. However, another crop species may be selected.