Evaluation of yield, yield components and nitrate leaching in soybean cultivation affected by different types of fertilizers and weed interference

Among the several factors reducing plants yield, weed interference has great important. To investigate the effect of fertilizer types and weeds management on yield, yield components and nitrate leaching in soybean an experiment was conducted as split plots in randomized complete block design with three replications in Chalus city in summer of 2013 and 2014. Fertilizers types including chemical fertilizer, manure and nano-chelates spraying as the main plot and weed control in three levels including emergence to flowering, critical period of weed interference and no weeding were considered as sub-plots. The results showed that yield with weeding during the critical period as well as weeding until flowering was achieved in a statistical group and were significantly more than non-control treatment. The highest weeds dry weight was obtained in gweed infested treatment and increasing in weed control time caused their weight loss. Among the fertilizer treatments, the highest dry weed weight was observed by chemical fertilizer application. Maximum nitrate concentration at a soil depth of 80-100 cm were obtained by using chemical fertilizer. Weeds dry weight increased and the nitrate concentration decreased when the weeds control duration was reduced. In general, the results showed that weed control during the critical period increased the grain yield by increasing the yield components.