Evaluation of agronomic parameters and seed quality of sunflower in response to different regimes of nitrogen, irrigation and zeolite

To decrease the use of chemical fertilizers and improving the yield and yield components of sunflower, a field experiment was conducted at the Reserch Farm of Tarbiat Modares University in 2014 and 2105. Three irrigation regimes (irrigation after depleting 40, 60 and 80 percent of soil water at field capacity (FC)), three soil fertility systems (100 percent farmyard manure (35 percent chicken manure 65 percent sheep manure), 50 percent farmyard manure 50 percent chemical fertilizer and 100 percent chemical fertilizer (urea)) and three zeolite rates (0, 5 and 10 ton ha-1) were studied in a split factorial arranged in a randomized complete block design with three replications, with irrigation regimes as the main plots, and factorial combination of the other two factors as the subplots. Over two experimental years, there were significant increases in grain yield and water use efficiency by applying either 100 percent farmyard manure (28.2 .6 ton sheep chicken manure ha-1, respectively) or integrated fertilizer (14.1 7.3 ton sheep chicken manure ha-1, respectively plus 65 kg urea ha-1) with 5 or 10 ton zeolite ha-1 under all irigation treatments. Based on the results, irrigation after depleting 40 percent of soil water at FC was revealed as most performance of all treatment combinations. The highest oil and protein concentrations of grain were obtained with zeolite application under non-stress conditions. Chemical fertilizer application increased grain protein concentration, while organic manure increased grain oil concentration.