%0 Journal Article
%T The effect of nitrogen fertilizer rate on summer maize yield and soil water-nitrogen dynamics<br>施氮量对夏季玉米产量及土壤水氮动态的影响
%A Wang Xin
%A Wang Zhaohui
%A Li Shengxiu
%A <br>王西娜
%A 王朝辉
%A 李生秀
%J 生态学报
%D 2007
%I 
%X A field experiment was carried out to study the effect of nitrogen (N) fertilizer rate (0, 120 kg N hm -2 , and 240 kg N hm -2 ) on summer maize (Zea mays L. var. Shaandan 911) and soil water-nitrogen dynamics. The dryland study was conducted in the southern part of the Loess Plateau during the warm and rainy summer of 2004 on a soil with high amounts of residual mineral N. The results showed that appropriate N application rates increased crop biomass and grain yield. Over application of N fertilizer did not increase crop biomass or yield. In the over-fertilized plots, N use efficiency was only 3.9% and N residual efficiency was as high as 87.2%. Water distribution in the soil profile was significantly influenced by the N rate. The 240 kg N hm -2 treatment contained 593 mm of water at harvest and the water had moved to a depth of 200 cm. In comparison, the 0 kg N hm -2 treatment contained 561 mm of water and the 120 kg N hm -2 contained 553 mm of water. In both treatments, water had moved to a depth of 180 cm. Nitrogen rates significantly affected the accumulation and distribution of nitrate N in the soil profile, but had no significant effect on the amount or distribution of ammonium in the soil profile. At harvest, total nitrate N in the 0-200cm depth was 78 kg hm -2 in the 0 kg N hm -2 treatment compared to 148 kg hm -2 in the 120 kg hm -2 and 290kg hm -2 in the 240 kg hm -2 . Nitrate N had moved down to a depth of 60 cm in the 0 and 120 kg hm -2 treatments and 140cm in the 240 kg hm -2 treatment due to percolation during the summer rainfall. The results suggest that appropriate N application rates could promote the utilization of soil water and mineral N by summer maize and increase its biomass and grain yield. In contrast, over application of N results in the accumulation of a large amount of nitrate N in the soil profile and increases the risk of nitrate N leaching to the subsoil. In addition, it was observed that nitrate N leaching is significantly slower than the downward movement of soil water.
%K dryland soil
%K nitrogen fertilizer
%K summer maize
%K nitrate N
%K ammonium N<br>旱地土壤
%K 氮肥
%K 夏玉米
%K 硝态氮
%K 铵态氮
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=90BA3D13E7F3BC869AC96FB3DA594E3FE34FBF7B8BC0E591&jid=FE163E5DB2274E5937319DE98913EC37&aid=365577C8DDC99158&yid=A732AF04DDA03BB3&vid=DB817633AA4F79B9&iid=CA4FD0336C81A37A&sid=33FB38C01AEC91E0&eid=3FAC7B9717FE816128A9B51B8D5A7FC0&journal_id=1000-0933&journal_name=生态学报&referenced_num=16&reference_num=36