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利用三峡库区分区县农业统计资料,对OECD土壤表观氮平衡模型进行适当改进,计算分析三峡库区1980~2005年农业用地氮平衡时空变化格局及驱动机制.结果表明,1980~2005年库区氮总输入和总盈余量呈显著增长趋势,分别从23.4万t和14.4万t增长到45.6万t和30万t;氮总输出量1980~1995年呈增加趋势,从9.0万t到16.7万t,1995年后基本保持稳定趋势;单位面积氮盈余量1980~1998年总体呈持续增加趋势,从133.4 kg/hm2增长到310.3 kg/hm2,1998年后逐步趋向稳定,但空间分布区域差异性增强,主要集中在库中和库首区县,与库区移民数量空间分布具有一定的相似性;氮输入贡献主要来源于化肥、牲畜粪便、人粪尿和生物固氮,累计占总输入90%以上;1995年前库区氮平衡变化主要受国内大量使用化肥宏观环境影响,1995年后受水库淹没和移民影响较大,但其具体影响程度有待进一步分析;建议考虑适当发展副业、改变农业种植结构或进行生态移民等措施减少氮排放量.
Based on the agricultural statistical data of the Three Gorges Reservoir Area, the apparent surface nitrogen balance model of OECD was properly improved to calculate and analyze the spatio-temporal variations of nitrogen balance in agricultural land from 1980 to 2005 in the Three Gorges Reservoir Area and its driving mechanism.The results show that from 1980 to 2005, The total nitrogen input and total surplus in the district showed a significant increase, increasing from 234,000 t and 144,000 t to 456,000 t and 300,000 t respectively. The total nitrogen output increased from 90,000 t to 16.7 The average nitrogen surplus per unit area increased continuously from 133.4 kg / hm2 to 310.3 kg / hm2 from 1980 to 1998. The spatial distribution was significantly different The main contribution of nitrogen input comes from the fertilizers, livestock excrement, human excrement and biological nitrogen fixation, which account for 90% of the total input %; Before 1995, the change of nitrogen balance in the reservoir area was mainly affected by the macroeconomic environment of extensive use of fertilizers in China. After 1995, it was greatly affected by the inundation of reservoirs and immigrants, but the specific impact needs to be further analyzed. , Change the structure of agricultural planting or ecological migration and other measures to reduce nitrogen emissions.