Effect of Different Levels of Nitrogen and Zinc Fertilizers on Qualitative and Quantitative Characteristics of Sunflower Seeds

To investigate the effect of nitrogen and zinc elements on the quantity and quality characters of sunflower plants (Jamah1cultivar), a factorial experiment in a randomized complete block design with three replications was conducted at the University of Zabol, Zabol, Iran in 2013. The experiment consisted of three nitrogen levels: 100, 200 and 300 kg ha-1 as the first factor and three levels of foliar application of Zinc including: 0 (control), 1.5 and 3 g L-1 of zinc sulfate solution as the second factor. Results showed that, application of nitrogen significantly increased the grain yield, biological yield, head diameter and 1000 seeds weight. The greatest grain yield, biological yield, 1000 seeds weight and head diameter were obtained at the 300 kg ha-1 of N treatment; it increased the latter attributes by 46.1, 7.2, 28.8 and 21.2% compared to 100 kg ha-1 respectively. In contrast to the potassium and oil content of the seeds, application of nitrogen fertilizer significantly increased the N, P and Zn content of the seeds. Foliar applied zinc led to significant increase in grain yield and all yield components; the grain yield increased by 21.5% at 3 g L-1 of zinc compared to the control. Foliar application of zinc also led to significant increase in the seed nitrogen, phosphor and zinc content. Application of 300 kg ha-1 of N along with 3 g L-1 Zn were found more appropriate for achieving maximal sunflower grain yield under the conditions of the present experiment.