Effects of Different Application N-fertilizer on Agronomic Characters of Spring Soybean

This experiment was carried out to design 4 kinds of top-application of N-fertilizer(150 kg/hm2) by the use of Jiyu 47 as material to study the effects of different growth period of agronomic characters of spring soybean.The result showed that with the nitrogen fertilizer increase,mid-upper internodes,mid-upper internode leaf area,mid-upper length of leaf stalk,leaf area index and stem diameter were redused,the included angle between mid-upper leaf stalk and main stem was increased,the pod number per plant,seed number per plant,yield per plant and the total yield were firstly increased,then decreased.There was no significant change in the top internode,the leaf area,the top length of leaf stalk,the weight of 100 seeds.The total yield was the highest when the spring soybean was treated with N-fertilizer of 45 kg/hm2 at initial podding stage.