Effects of Nitrogen Fertilizer on Growth and Water Use Efficiency of Maize in Sandy-loam Alluvial Soil

In order to ascertain the characteristics of growth and water utilization of maize under different amount of nitrogen fertilizer,a field experiment was conducted to investigate the effect of nitrogen fertilizer with dosage of 0kg/ha(CK),90kg/ha(N1),180kg/ha(N2),270kg/ha(N3),360kg/ha(N4),450kg/ha(N5),540kg/ha(N6)on soil moisture,maize agronomic characters,production elements,yield and water utilization.The results indicated that application of nitrogen fertilizer,especially 450kg/ha increased the upper soil water content,and promted the maize root deep growth,so the maize could rse more deep soil water.The corn morphological indexes of the treatment with 450kg/ha nitrogen in different growth period had better performance,and the production elements such as ear length,ear coarse,ear number of rows,row grains were higher compared with CK.With the increase of nitrogen rate,maize yield increased significantly,but when nitrogen fertilizer was higher than 450kg/ha,the increase rate of maize yield decreased obviously.And water use efficiency first increased and then dropped with the increase of nitrogen.The water use efficiency(WUE)of the treatment with 450kg/ha nitrogen was highest and the yield(12 093.0kg/ha)and WUE([24.4kg/(mm·hm2)])were 70.7% and 78.1% higher than CK.It was concluded that the treatment with 450kg/ha nitrogen was the most promising option.