EFFECT OF POTASSIUM, ZINC AND MANGANESE ON AGRONOMIC TRAITS OF SOYBEAN

In order to evaluation of the potassium, zinc and manganese effects on agronomic traits of soybean, a factorial experiment was conducted on 2008 growing season with three replications at Kohne-kan research field in Bojnourd, Iran. This experiment was done based on RCBD design. Treatments were, potassium in three level( 0, 80 and 160 kg/ha K2O in form of potassium sulphate fertilizer) and application of micronutrients including of, control, Zinc Librel, Manganese Librel, Zinc + Manganese Librel (1.5/1000 v/v) and also Solopotash, trade mark for soluble potassium sulphate, spraying (2/1000 v/v). Results showed potassium had no significant effects on yield, but Zn2+ +Mn2+ , and Solopotash increased yield via effect on yield components. The highest seed yield was obtained from application of Solopotash alone, about 4767 kg/ha. This is a result of increasing in seed number per pod, branch number and seed weight at that treatment. The greatest seed per pod was obtained from 160 kg/ha K2O + Solopotash. Application of only Mn2+ , increased the harvest index.