摘要
一个地实验被进行在冬小麦(Triticum aestivum L.) 和夏天玉米(Zea mays L.) 下面调查 15N 标签脲和它的剩余效果的命运诺思中国平原上的旋转系统。比作 360 kg N 的常规申请率哈 ? 1 (N360 ) ， 120 kg N 的减少的率哈 ?(N120 ) 1 导致了重要增加(P 【
0.05 ) 在小麦，产量和没有重要差别被作出对有利的裁决玉米。在在收获的 0 100 厘米土剖面，与 N360 相比， N120 不管多么导致了重要减少(P 【
0.05 ) 百分比剩余 N 和百分比未予说明的 N，它可能从管理系统反映了损失。在土剖面的剩余化肥 N 25.6%44.7%和20.7%分别地，，38.2%为 N120 和 N360 在器官的 N 水池0.3%3.0%和11.2%相应地，24.4%在硝酸盐水池，显示一个更高的潜力因为沥滤的损失以常规率与申请联系了。在由接替庄稼的土剖面的剩余 N 的恢复是不到 7.5% 应用 N。为 N120，全部的土壤 N 平衡是否定的；然而，仍然有可观的矿物质 N (NH+4-N 并且没有 ? 3-N ) 在在收获以后的土剖面。因此， N120 能在短期内被认为农学的联盟者可接受，要不是长期的可持续性， N 率应该基于土壤矿物 N 测试和植物组织硝酸盐测试被推荐维持土壤肥力。
A field experiment was conducted to investigate the fate of ^15N-labeled urea and its residual effect under the winter wheat （Triticum aestivum L.） and summer maize （Zea mays L.） rotation system on the North China Plain. Compared to a conventional application rate of 360 kg N ha^-1 （N360）, a reduced rate of 120 kg N ha^-1 （N120） led to a significant increase （P 〈 0.05） in wheat yield and no significant differences were found for maize. However, in the 0-100 cm soil profile at harvest, compared with N360, N120 led to significant decreases （P 〈 0.05） of percent residual N and percent unaccounted-for N, which possibly reflected losses from the managed system. Of the residual fertilizer N in the soil profile, 25.6%-44.7% and 20.7%-38.2% for N120 and N360, respectively, were in the organic N pool, whereas 0.3%-3.0% and 11.2%-24.4%, correspondingly, were in the nitrate pool, indicating a higher potential for leaching loss associated with application at the conventional rate. Recovery of residual N in the soil profile by succeeding crops was less than 7.5% of the applied N. For N120, total soil N balance was negative; however, there was still considerable mineral N （NH4^＋-N and NO3^--N） in the soil profile after harvest. Therefore, N120 could be considered ngronomically acceptable in the short run, but for long-term sustainability, the N rate should be recommended based on a soil mineral N test and a plant tissue nitrate test to maintain the soil fertility.
基金
Project supported by the National Natural Science Foundation of China (Nos. 40571071, 30390080 and 30370287)
the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT0511).
关键词
尿素
冬小麦
玉米
中国
平原
^15N-labeled urea, nitrogen recovery, nitrogen residual effect, North China Plain, winter wheat-summer maize rotation
