Quantitative and qualitative reaction of common bean (Phaseolus vulgaris L.) to phosphorous and zinc sulfate application method under different rates of nitrogen starter fertilizer

To investigate the effect of application method of phosphate and zinc sulfate fertilizers on yield and seed protein percentage, phosphorus and zinc in common bean cultivar which was inoculated with Rhizobium leguminosarum, a factorial experiment was conducted in a randomized complete block design with three replications at Bu-Ali Sina University in 2015-2016. In this experiment, three factors consist of N fertilizer (0, 30 and 60 kg N ha-1), zinc sulfate (soil broadcasting and foliar feeding) and phosphate application method (soil broadcasting and placement near the seed) were considered. The highest number of pods per plant, number of seeds per pod, grain yield and biological yield of beans were 14.25, 4.98, 3180 and 10197 kg ha-1, respectively, which obtained from 30 kg N ha-1 + phosphate placement + foliar feeding of zinc sulfate and were increased 90, 81, 88 and 95.34%, compared to control treatment (soil broadcasting of phosphate and zinc sulfate without nitrogen). The phosphate placement at 0 and 30 kg ha-1 of nitrogen increased seed protein by 23.6% and 20.7%, respectively, and also increased the grain phosphorus concentration by 34%. Foliar zinc sulfate increased the protein and Zn concentration of the seed, by 16% and 13%, respectively, compared to soil broadcasted application. Based on the results, 30 kg ha-1 nitrogen starter application with phosphate placement plus zinc sulfate foliar spraying is a suitable treatment to improve the quantity and quality of bean seeds.