Evaluation of the effect of spatial distribution of weeds on seed yield of lentil (Lens culinaris L.) in rainfed conditions

Weeds are one of the most important factors in reducing yield in legumes crops. Therefore, awareness of the interaction between weeds and crops as well as identification of their spatial variation pattern in the field is important. To investigate the the effect of  weeds on seed yield of lentil, and also to study the spatial distribution pattern of weeds under rainfed conditions, a field experiment was conducted in research field of agricultural and natural resources campus, Razi University, Kermanshah, Iran, in 2016. Systematic samplings and measuremnts weeds characteristics (density, canopy percentage, height and dry weight) and lentil (canopy percentage and seed yield) were carried out in two stages; pre-flowering and physiological maturity of lentil. The relationships between weeds and lentil were studied using regression and maps of weeds and lentil traits using Kriging interpolation method. The results showed that by increasing the density and canopy percentage of weeds from 0 to 10 (plants.m-2 or percentage), the seed yield of lentil decreased by 6.2 and 6.7 g.m-2, respectively. Furthermore, increasing weeds dry matter from 0 to 10 g.m-2 led to a decrease in lentil seed yield by 2.4 g.m-2. The spatial distribution maps also clearly showed the spatial variations of seed yield under the influence of weeds. In conclusion, the results of this study showed that spatial maps of weeds and lentil traits distributionas well as conventional statistical methods are complementary and accurate method for better understanding of the relationships between them.