江苏太湖稻麦两熟地区生态、经济施氮量的初步研究

田间试验结果表明 ,水稻、小麦产量随着施氮量的增加而增加 ,但单位氮素的产量、边际产量以及生产弹性系数、产投比均随着施氮量的增加而下降。稻、麦籽粒氮肥当季利用率均随着施氮量的增加而表现为先增后降 ,秸秆氮素利用率基本上呈上升的趋势 ,说明在该地区稻麦两熟制度中存在着氮素奢侈吸收现象。应用传统经济学和环境经济学方法求算出当地稻麦两熟的周年生态、经济施氮量分别为 2 81 .9和 3 3 6.3 kg/ hm2 。

ECOLOGICAL AND ECONOMIC NITROGEN APPLICATION AMOUNT OF RICE AND WHEAT IN TAI LAKE AREA OF JIANGSU PROVINCE

Field experiment results show that yields of rice and wheat increase, but unit nitrogen yield, marginal yield, production elastic coefficient, ratio of output to input value decrease with the increase of nitrogen application amount. Current season nitrogen fertilizer utilization rate of seeds of wheat and rice increases first, then decreases, but that of straw is in increasing trend with the increase of nitrogen fertilizer application amount, which means that straw absorbs nitrogen extravagantly. Annual ecological and economic nitrogen fertilizer application amounts in this rice and wheat double maturing area are 281.9 kg/hm 2 and 336.3 kg/hm 2, respectively, with the calculation methods of traditional economics and environmental economics.