Competition of some summer catch crops and volunteer cereals in the areas with limited precipitation

Competitive ability of six summer catch crops (Brassica napus, Lolium multiflorum, Lolium perenne, Phacelia tanacetifolia, Sinapis alba and Trifolium incarnatum) in volunteer winter wheat based on field trials was experimentally tested during the years 2004-2007 in central Bohemia (Czech Republic). The production of aboveground biomass and plant cover of sown catch crops, volunteers and weeds was assessed on experimental plots. General linear models revealed significant influence of catch crops, year and their interaction on dry-mass of the volunteers. The lowest average values of volunteer biomass at the end of the growing season (average from 2004-2007) were recorded on plots sown with S. alba (124.7 kg/ha) and P. tanacetifolia (186.3 kg/ha). The average biomass of volunteer plants in stands of S. alba was significantly lower than the biomass of volunteers in stands of L. perenne, L. multiflorum and T. incarnatum. The lowest average biomass of weeds was recorded also in S. alba stands.