Optimal Combination of Nitrogen Fertilizer and Spring Soybean Varieties in Chongqing

Three soybean varieties,including Tedou No.1,Zhechun No.3 and Tedou No.5 were selected,and three nitrogen level(0,90,120 kg·ha-1)were applied,to study the effect of N and variety combinations on main agronomic characters,yield and yield components of spring soybean.When Tedou No.5 was growing under 90 kg·hm-2 nitrogen,the seed nitrogen content,nitrogen utilization efficiency and yield were all higher than other treatments,and the yield reached 2 240 kg·ha-1.In three tested varieties,Tedou No.5 had higher nitrogen utilization efficiency,while Zhechun No.3 was sensitive to nitrogen.Significant interaction existed between nitrogen rate and varieties,and the treatment combination A2B3(Tedou No.5 growing under 90 kg·ha-1 nitrogen)got the highest yield.