ارزيابي روش هاي كاربرد نيتروژن بر عملكرد و اجزاي عملكرد هيبريد آلستار آفتابگردان

Evaluation of Nitrogen Application Methods on Yield and Yield Components in Alestar Sunflower Hybrid

In order to evaluate nitrogen effect on yield and yield components in sunflower, a split-factorial experiment was carried out at Agricultural Research Station of Tabriz Islamic Azad University. The experiment was arranged in a randomized complete block design with three replications. Treatments were time of nitrogen application to soil (N1. application of 1/2 nitrogen at planting time+ 1/2 at vegetative stage, N2: application of 1/3 nitrogen at planting time + 1/2 at vegetative stage + 1/3 at flowering stage and N3: application of 1/4 nitrogen at planting time+ 1/2 at vegetative stage + 1/4 at flowering time), foliar application of nitrogen at different growth stages ( S1: foliar application of N at 8-10 leaf stage and S2: foliar application of N at flowering stage) and foliar application of concentrated nitrogen ( C1: foliar application with 3% urea concentration and C2: foliar application with 5% urea concentration). When crop was harvested, traits such as head diameter, harvest index, seed number per head, filled seed number, 100 seed weight and seed yield per hectare were measured. Results showed that application of 1/2 N at planting time + 1/2 at vegetative stage resulted in higher seed yield than other treatments, by about 75.89% (3.04 T/ha). Foliar applications of N at 8-10 leaf stage was about 9.52% more effective in harvest index, filled seed number and seed number per head as compared with foliar application of N at flowering stage. Results also revealed that foliar application with 5% urea concentration increased head diameter, seed number per head and filled seed number by about 5.9% as compared to 3% urea concentration. It can, thus, be concluded that soil application method of nitrogen, due to its lower cost and ease of application, could be recommended to the farmers.