Quantitative and qualitative response of peanut (Arachis hypogaea L.) to starter nitrogen application

In order to evaluate the quantitative and qualitative yield of peanut (Arachis hypogaea L.) in response to starter nitrogen rates two separate experiments were performed in 2013 and 2014 cropping season as randomized complete block design with three replications, in experimental field of Agricultural and Natural Resources Research and Education Center of Guilan Province, Rasht, Iran. Four rates of nitrogen including of zero, 100, 150 and 200 kg/ha comprised the experimental treatment. The results of this research showed that with increment of starter nitrogen application, duration of developmental stages in peanut enhanced. The greatest pod (3561 kg/ha) and seed yield (1740 kg/ha) of peanut, grain oil (49.86 percent) and nitrogen content (3.91 percent), oil yield (867 kg/ha) and protein yield (426.5 kg/ha) were obtained at 100 kg N/ha level. Application of 150 kg N/ha showed superiority for pod number per plant (21.30) and grain number per pod (1.39). Also, application of 200 kg N/ha caused to enhance plant height (73.35 cm) and grain phosphorus content (0.437 ppm) in peanut. In addition, there was negative and significant correlation between grain yield and some traits such as day number to initial flowering, day number to the end of flowering and maturity. The correlation coefficient between grain yield and oil (r= 0.99**) and protein yield (r= 0.89**) was positive and significant. In this experiment, oil and protein yield of peanut per unit area mostly related to grain yield. In general, results showed that the application of starter nitrogen up to 100 kg/ha enhanced pod and grain yield of peanut and oil and protein yield in Guilan province climatic condition.