The impact of integrated management of nitrogen fertilizers on growth indices, yield ‎and qualitative characteristics of potato (Savalan cultivar)‎

This experiment was conducted to investigate the influence of integrated management of nitrogen fertilizers on growth, yield and quality characteristics of potato (Solanum tubersom cv Savalan) in Behbahan Agriculture Research Stations from 2014 to 2016. This research was carried out in randomized complete block design including four treatments: lack of nitrogen fertilizer (control), plots that received 50% nitrogen from chemical fertilizer (as urea) plus 50% nitrogen from vermicompost (50%U+50%V), plots that received 75% nitrogen from chemical fertilizer plus 25% nitrogen from vermicompost (75% U+25%V), and plots that obtained 100% nitrogen from chemical fertilizer (100% urea) and three replications. The Results of growth analysis showed that the haulm and tuber growth rate increased during the early stages, while reached a maximum value, following decline in the late season. In the most sampling periods, the highest tuber and crop growth rate were recorded in 75% urea +25% vermicompost. Therefore the highest yield was observed in this treatment. Application of vermicompost significantly increased tuber number, total and marketable yield, nitrogen use efficiency and agronomic nitrogen use efficiency in 75% urea +25% vermicompost and 50% urea +50% vermicompost as compared with 100% urea. The tuber nitrate content in   75% urea +25% vermicompost and 50% urea +50% vermicompost was significantly lower than 100% urea. According to results, the yield and qualitative characteristics of potato (Savalan cultivar) and farmers’ incomes can increase in Khuzestan province by supply of 75% required nitrogen fertilizer through urea and 25% nitrogen from vermicompost.