太湖流域稻麦轮作系统实际施氮量及其多重效应——基于农户调研的实证分析

研究运用分层随机抽样法,在常州市武进区开展农户问卷调查,并利用统计软件对问卷信息进行整理和分析,得到主要结论如下:①太湖流域稻麦轮作系统稻季平均施氮量为310.91 kg·hm^-2,麦季平均施氮量为202.18 kg·hm^-2,一年两季作物平均施氮量为513.09 kg·hm^-2,氮肥过量施用现象主要存在于稻季;②施氮肥对水稻和冬小麦都具有较好的增产作用,但是当施氮量达到一定值后,水稻和冬小麦的产量、氮素累积量、氮肥农学利用率和氮肥吸收利用率都出现下降的趋势;③太湖流域稻麦轮作系统土地氮剩余量和面源氮排放量随着施氮量的增加而持续增加,在目前的氮肥施入水平下一年两季作物的氮素流失量约为41.26 kg·hm^-2。

Actual Nitrogen Rate and Its Multiple Effects in Rice-Wheat Rotation System of Taihu Lake Watershed: Empirical Analysis Based on Household Survey

The authors carried out a one-week household survey with stratified random sampling in Wujin District of Changzhou in 2009, then organized and analyzed data from a total of 237 questionnaires using SPSS statistical software. Main conclusions are as follows: 1) Actual nitrogen rate in rice-wheat rotation system of Taihu Lake Watershed was 513.09 kg·hm^-2 per year with 310.91 kg·hm^-2 in the rice season and 202.18 kg·hm^-2 in the wheat season, which revealed that excessive application of nitrogen mainly existed in the rice season. 2) Nitrogen played an active role in increasing yield of rice and wheat, but their yield, nitrogen accumulation, agronomic efficiency and recovery efficiency tended to decrease when nitrogen rate climbed to a certain point. 3) Nitrogen surplus and loss continued to increase as nitrogen rate rose in rice-wheat rotation system of Taihu Lake Watershed and nitrogen loss was estimated to be 41.26 kg·hm^-2 per year under current nitrogen rate.