Nitrogen dynamics and budgets in a winter wheat-maize cropping system in the North China Plain
Nitrogen dynamics and budgets in a winter wheat-maize cropping system in the North China Plain
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DOI：
10.1016/s0378-4290(03)00068-6
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发表时间：
2003-08-20
影响因子：
5.8
通讯作者：
Christie, P
中科院分区：
文献类型：
--
作者：
Liu, XJ;Ju, XT;Christie, P
研究了华北平原粘壤土（草甸湖）冬小麦氮素动态和收支特征。和玉米（Zea mays L.）种植制度比较了四个氮水平（0，120，240和360 ka N ha（-1）尿素）的影响，每种作物两次超过2年。施用氮肥后，土壤剖面中铵态氮（NH 4-N）保持在较低的稳定水平（表层20 cm除外）。与此相反，硝态氮（NO3 N）水平显着改变施氮量。在小麦和玉米生长季节，每茬施氮量为240和360 kg/ha（N240和N360）时，NO3-N有从表层向下层（20-100 cm）迁移的强烈趋势。N240和N360处理土壤剖面中NO3-N的累积量显著高于N 0和N120处理（每茬0和120 kg N ha（-1）处理）。2年后，N120、N240和N360 0 0-300 cm深度土壤NO3-N含量分别为336、815和1141 kg ha（-1），其中一半以上分布在100-300 cm层。计算的总氮平衡表明，大部分肥料氮是有效的NO3-N在顶部300厘米的土壤剖面使用传统的施肥和灌溉措施。在随后的2年中，计算出N120中的氮损失相对较低，但N240和N360中的氮损失显著较高。气态氮损失的测量结果表明，NH3挥发和反硝化只包括一小部分的总氮损失在2年的旋转，而NO3-N淋溶从顶部100厘米的土壤剖面占大多数的N损失在所有的N率和实验年。氮素收支分析表明，在冬小麦-玉米种植系统中，NO3-N在100 cm以下的积累和淋溶是氮素流失的主要途径。推荐的施氮量为120 kg N ha（-1），在保持冬小麦和玉米高产和氮素利用的同时，最大限度地减少了土壤NO3-N的累积和淋失。(C)2003 Elsevier Science B. V.保留所有权利。
Nitrogen dynamics and budgets in a clay loam soil (Meadow Aqualf) in the North China Plain were investigated in a winter wheat (Triticum aestivum L.) and maize (Zea mays L.) cropping system comparing the effects of four N rates (0, 120, 240 and 360 ka N ha(-1) as urea) applied twice to each crop over 2 years. Ammonium nitrogen (NH4-N) in the soil profile remained at a low and constant level (except in the surface 20 cm layer) following application of fertilizer N. In contrast, nitrate nitrogen (NO3N) levels were significantly altered by the rate of applied N. A strong tendency of NO3-N to move from the surface layer to the lower layers (20-100 cm) was observed during the wheat and maize growth seasons in treatments of 240 and 360 kg N ha(-1) per crop (N240 and N360). The amounts of NO3-N accumulated in the soil profile were significantly higher in N240 and N360 than those in N0 and N120 (treatments receiving 0 and 120 kg N ha(-1) per crop). After 2 years, soil NO3-N levels at 0-300 cm depth in N 120, N240 and N360 amounted to 336, 815 and 1141 kg ha(-1) respectively, with more than half of these amounts distributed in the 100-300 cm layer. The calculated total N balance indicates that most fertilizer N was available as NO3-N in the top 300 cm of the soil profile using traditional fertilization and irrigation practices. Over the subsequent 2 years, N losses were calculated to be relatively low in N120 but significantly higher in N240 and N360. Measured gaseous N losses showed that NH3 volatilization and denitrification comprised only a small fraction of total N losses during the 2-year rotation, while NO3-N leaching from the top 100 cm of the soil profile accounted for most N losses across all N rates and experimental years. The N budget showed that accumulation and/or leaching of NO3-N below 100 cm depth (beyond the reach of most roots) was the main pathway for N losses in the winter wheat-maize cropping system. The recommended N application rate of 120 kg N ha(-1) minimized soil NO3-N accumulation and leaching losses while maintaining high yields and N utilization by winter wheat and maize. (C) 2003 Elsevier Science B.V. All rights reserved.