Study on Nitrogen Fertilization in Rotation of Winter Wheat and Summer Maize in Southern Shanxi

The rotation of winter wheat and summer maize is a major planting system in southern Shanxi.This field experiment was conducted in a randomized design with four replicates to study the influence of nitrogen distribution on yield,net return,nitrogen agronomic efficiency and nitrogen use recovery in rotation of winter wheat and summer maize based on the amount of nitrogen controlled(420 kg/hm2).The results showed that the proportion of nitrogen distribution significantly affected the yield,net return and nitrogen use efficiency in the rotation.Under the condition of 420 kg/hm2 nitrogen fertilization,the proportion of 55%(231 kg/hm2) applied on winter wheat and 45%(189 kg/hm2) for summer maize could help obtain the highest production(13 026 kg/hm2) and net return(22 146 $/hm2),and the agronomic efficiency and recovery of nitrogen fertilizer was increased.This indicated that the proportion of nitrogen distribution in the rotation was feasible for southern Shanxi province.It was important to point out that as crop suffered from adverse weather at growth stage,it led low nitrogen agronomic efficiency and nitrogen use recovery with the average value only 4.6 kg/kg and 20.8%,respectively.