Modelling of Interaction between Fertilizer Rates and Nicosulfuron Herbicide Doses on Grain Yield and Biomass of Corn



In order to modeling the output required in corn, an experiment was conducted with a factorial arrangement based on a randomized complete block design with three replications at Research Fields of University of Tehran in 2007. Two factors including four levels of N fertilizer (0, 180, 270, and 360 kg ha-1of Urea fertilizer 46 %) and five doses of Nicosulfuron herbicide (0, 20, 40, 60, and 80 g. ai ha-1) were used. According to the equation fitted on data, to achieve high yield, 250 kg ha-1 N fertilizer and 38 g ai ha-1 Nicosulfuron herbicide dose (i.e reaching to the 50 % of the yield) are needed. Also, the data fitted by line level showed that the highest corn grain yield (almost 11 t ha-1) and corn biomass (8 t ha-1) were observed with 270 kg ha-1 N fertilizer and 80, 60 g. ai ha-1 Nicosulfuron herbicide treatments. Besides, the lowest corn grain yield and biomass yield (3 t ha-1) were obtained in the treatment used no N fertilizer and herbicide dose. The results showed that application of N fertilizer up to 360 kg ha-1 resulted in higher herbicide dose used for appropriate weed control. Consequently, N fertilizer must be applied in farm based on weed density and species.