摘要
在黄土高原南部旱地有大量氮素残留背景的田块上，研究了不同氮肥用量对夏玉米生长及对土壤水分、硝态氮、铵态氮累积及其剖面分布的影响。结果表明：适量施氮可以提高作物产量；过量施氮没有表现出增产效果，其氮肥利用率只有3．9％，残留率则高达87．2％。施氮240kghm^-2时，0～200cm土层土壤水分达到593mm，且可以下渗到200cm土层；不施氮和施氮120kghm^-2以小区土壤的蓄水量分别为561和553mm，可下渗到180cm。对矿质态氮而言，施氮量可以显著影响土壤中硝态氮的累积和分布，但对铵态氮的影响较小；施氮0，120，240kghm^-2时．收获期土壤硝态氮累积量分别为78，148，290kghm^-2，硝态氮的下移前沿分别到达60，60，140cm。可见，适量施氮会促进作物对土壤水氮的利用。提高作物生物量和产量；过量施氮导致硝态氮在土壤中大量累积，提高硝态氮随水分淋溶危险；但硝态氮向下层土壤的移动显著滞后于水分。
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. vat. 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 nun 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-2in 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^-3 treatments and 140cm in the 240 kg hm^-5 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 wa
出处
《生态学报》
CAS
CSCD
北大核心
2007年第1期197-204,共8页
Acta Ecologica Sinica
基金
国家自然基金青年基金资助项目(40201028)
国家自然科学基金面上资助项目(40671107
30370843)
国家自然基金重点资助项目(30230230)
国家农业部"948"重大研究资助项目(2003-Z53)~~
关键词
旱地土壤
氮肥
夏玉米
硝态氮
铵态氮
dryland soil
nitrogen fertilizer
summer maize
nitrate N
ammonium N
