با استفاده از شاخص هاي رقابت TRITICUM AESTIVUM L. و گندم پاييزه SINAPIS ARRENSIS L. تحليل رقابت خردل وحشي

Analysis of competition between wild mustard (Sinapis arvensis L.) and winter wheat (Triticum aestivum L.) by competition indices

In order to describe competitive relationships between winter wheat and wild mustard by competition indices, an additive series experiment was conducted in 2001- 2002 at agricultural research station of Mashhad University. The experiment had 3 factors: 3 levels of wheat seed rate (175, 215 and 225 kg/ha), 2 levels of nitrogen rate at optimum and upper optimum rate of wheat (150 and 225 kg N/ha), and 4 levels of wild mustard density (0, 8, 16 and 32 plants/m2). Regression analysis was used to describe competitive relationships. The reciprocal of per plant model was used to determine intra and interspecific competitive coefficient. Plant relative competitive abilities (RCA) revealed that wild mustard was more competitors than wheat (based on wheat biomass RCA of 0.37 for wheat and wild mustard biomass RCA of 2.75 for wild mustard). Degree of nich differentiation for wheat and wild mustard decreased from 1.67 to 0.54 as nitrogen rate increased. Wheat relative competitive intensity (RCI) showed reduction in interspecific competition due to increasing in wheat seed rate.