The effect of row spacing and weed density on growth indices of canola in competition with wild mustard (Sinapis arvensis)

In order to evaluate the effect of row spacing and weed density on growth indices of canola (Brassica napus) in competition with wild mustard (Sinapis arvensis(a field experiment was conducted based on randomized complete block design with factorial arrangement and three replications at Agricultural Research Station of Agricultural Sciences and Natural Resources of Gorgan University, during 2009-2010 growing season. The factors included canola row spacings at 3 levels (12, 24 and 36 cm) and wild mustard densities at 4 levels (0, 4, 8 and 16 plant per m2). Results showed that growth indices of canola (leaf area index (LAI), crop growth rate, relative growth rate and total dry matter) decreased in competition with wild mustard in all row spacings of canola. The most leaf area of canola distributed at higher height of canola in row spacing of 12 cm as compared to 24 and 36 cm. According to the results, it seems that LAI and vertical distribution of canola’s leaf area in canopy are the effective indices in reducing wild mustard biomass and increasing competitive ability of canola in competition with wild mustard.