不同肥料结构氮在棉田生态系统中的吸收利用和去向研究

Study on Absorbing Utilization and Fate of Different Fertilizer Structure N in Cotton Field Ecosystem

采用^15N示踪方法，研究了棉田生态系统中化学N肥及其与绿肥、沼肥配合施用时N素的吸收利用和去向，结果表明：（1）在等N、P、K条件下，沼肥与化肥配施棉花增产效果显著，绿肥与化肥配施次之，单施化肥较差，这与单施化肥N素较多地积累在叶和无效蕾、花、铃中，有机肥与化肥配施N素较多地积累在生殖器官中密切相关。（2）棉株对土壤N的依赖性低于肥料N，但单施化肥棉株对土壤N的依赖性高于有机肥与化肥配施。棉株营养器官累积土壤N的比例大于生殖器官，说明棉株生育前期对土壤N的依赖性高于生育后期，充分说明棉花生产中重施花铃肥的重要性。（3）有机肥与化肥配施，肥料N在土壤中的残留率为单施化肥的2．5—3倍，而损失率后者为前者的1．4—1．6倍，表明有机肥与化肥配施改土效果明显。

With ^15N tracing method, this thesis studied chemical nitrogen fertilizer and the absorption and trace of nitrogen in it when it was used with green manure and methane manure together in cotton field ecosystem. The results were as follows： （ 1 ） Under the same quantities of nitrogen, phosphate and potassium, cooperative application of methane manure and chemical fertilizer had great effect on the increase of cotton yield, cooperative application of green manure and chemical fertilizer was the second, and sole application of chemical fertilizer was the worst. This result was because the nitrogen amount of sole chemical fertilizer was accumulated mostly in leaf and useless bud, blossom and bolls, while nitrogen amount in cooperative organic fertilizer and chemical fertilizer was mostly accumulated in reproductive organs. （2） The dependence of cotton plant on soil nitrogen was lower than that on fertilizer nitrogen, while the dependence on soil nitrogen under the condition of sole chemical fertilizer was higher than that under the condition of cooperative use of organic fertilizer and chemical fertilizer; the ratio of accumulated soil nitrogen in nutritive organ was higher than that in reproductive organ. All these showed that cotton plant depended on more soil nitrogen in the early period than in the latter period, which implied the importance of weightily using flower and boll fertilizer. （3） In cooperative application of organic fertilizer and chemical fertilizer, the remnant of fertilizer nitrogen in the soil was 2.5 -3 times comparably to that of sole application of chemical fertilizer, while the loss rate of the latter was 1.4- 1.6 times comparably to the former, which showed the effective result of soil improvement under the cooperative work of organic fertilizer and chemical fertilizer.