Sunflower (Helianthus annuus L.) grain yield affected by fertilizer and plant density

In order to study the effect of fertilizer and crop density on some agronomic traits in sunflower, a field experiment was carried out as a split-plot based on randomized complete block design with three replications in the Agricultural Research Farm of Dasht-e-Naz in Sari, Iran. Main plots included four fertilizer treatments (N0p 0K0, N23p 25K25, N46p 50K50 and N69p 75K75) and sub-plots included four plant densities (D50= 50000, D60= 60000, D70= 70000, and D80= 80000 plant ha-1). The results indicated that there was a significant difference in grain yield, biological yield, kernel, and oil yield (p < 0.01) and individual biological yield and the number of empty rows (p < 0.05) by plant density. There was a significant difference in grain kernel ratio (p < 0.05) by fertilizers. F2 and F1 had the maximum and minimum grain kernel ratio with 77.40 and 76.30%, respectively. D50 and D80 had the lowest and highest grain yield with 5666 and 3633 kg/ha, respectively. Biological yield in D60 was the lowest but in D80 was the highest with 10853 and 16460 kg/ha, respectively.D60 and D50 had the lowest and highest individual biological yield with 180.90 and 225.90 g/plant, respectively. The maximum and minimum grain yield was obtained in F3 (4817 kg/ha) and F2 (3968 kg/ha), respectively.