Effects of Different Types of Urea on Nitrogen Accumulation and Nitrogen Use Efficiency of Soybean

A field experiment with 7 treatments of different types of urea and several nitrogen rates was conducted to study the effects of controlled-release urea on soybean agronomic characteristics,nitrogen contents and seed yield.Polypeptide urea(PU),long-acting sustain-released urea(LSU),large granule urea and sulfur-coated urea improved the dry matter,nitrogen accumulation,nitrogen use efficiency(NUE) and seed yield compared to the common urea.The treatments of 60 kg·ha-1 PU and LSU increased dry matter,total accumulated nitrogen and NUE obviously,and at the pod filling stage,the three indexes increased by 11.1 and 18.1 g·m-2,0.83 and 1.11 g·m-2,10.73% and 15.16%,respectively.The treatments of75 kg·ha-1 PU and 60 kg·ha-1 LSU had best yield-increasing effect,and seed yield increased by 9.5% and 11.0%,respectively.