粮食主产区土地确权背景下：化肥、农药与粮食产量均衡关系研究*——以河南为例

THE EQUILIBRIUM RELATIONSHIP BETWEEN CHEMICAL FERTILIZER, PESTICIDE AND GRAIN OUTPUT UNDER THE BACKGROUND OF CONFIRMATION OF RURAL LAND RIGHT IN MAJOR GRAIN-PRODUCING AREAS*——BASED ON HENAN PROVINCE

关键词:  土地确权化肥农药断点回归长期均衡

Key words:  confirmation of land right  chemical fertilizer  pesticide  regression discontinuity  long term equilibrium

摘要:

［目的］粮食产量可持续性与土壤生态有着重要关系，而产量短期内又和化肥和农药的施用量有关。土地确权政策的明确有可能影响农民追求土地的长远回报。文章基于土地确权背景，以期为河南粮食生产的可持续性和土地生态保护提供对策建议。［方法］依据1991—2015年河南省的统计年鉴相关数据，运用断点回归模型检验土地确权政策是否影响农民施用化肥、农药数量； 同时运用协整模型研究小麦产量与化肥、农药施用量之间是否存在长期均衡关系，并通过冲击响应分析单位化肥、农药施用量的变化对粮食产量的影响以及化肥与农药之间彼此关系。在这检验过程中也对影响化肥、农药施用量其他因素进行了理论和实证分析。［结果］实证结果显示土地确权政策对农民施用化肥和农药数量的影响统计量Z均小于05。这表明土地确权政策对化肥和农药的施用量没有影响； 同时小麦的产量与化肥、农药施用量存在长期依赖关系，其中小麦产量对化肥施用量的相关依赖程度为0574 8，对农药施用量的依赖程度为0388 1； 在短期内化肥单位施用量的变化会对粮食的产量产生正向冲击，对农药施用量也产生正向冲击。［结论］土地确权政策短期内，农户仍然不会因考虑土壤生态而减少化肥、农药施用量。据此该文建议政府应改变粮食补贴与粮食产量挂钩等相关政策。

Abstract:

The sustainability of grain output is closely related to soil ecology, and the output is related to the usage amount of chemical fertilizer and pesticide in the short term. The confirmation of rural land right may affect the long term return of farmers in pursuit of land. Based on the background of the confirmation of rural land right, this paper highlighted the sustainability of grain production and the conservation of land ecology. According to the relevant data in the Statistical Yearbook of 1991—2015, we adopted a regression discontinuity model to test whether the policy confirmation of rural land rights affected the quantity of chemical fertilizers and pesticide applied by farmers, also we used the co integrated model to study whether there was a long term equilibrium relationship between wheat yield and the usage amount of chemical fertilizers and pesticide, and analyzed the impact of chemical fertilizers, the usage amount change of pesticide on grain output and the correlation of chemical fertilizers and pesticide, through impulse response. The results showed that: (Ⅰ) The statistical significance of the land based rights policy on the amount of chemical fertilizers and pesticides applied by farmers was less than 0.5. This indicated that the land rights policy had no effect on the application rate of chemical fertilizers and pesticides; meanwhile, there was a long term dependence on the yield of wheat and chemical fertilizers and pesticides; (Ⅱ) The dependence of wheat yield on chemical fertilizer application rate was 0.574 8, and the dependence on pesticide application rate was 0.388 1;(Ⅲ) In the short term, the change in the application rate of unit chemical fertilizers would have a positive impact on the yield of grain, and would also have a positive impact on the amount of pesticide applied. In general, farmers still had not reduced the amount of fertilizers and pesticides, regardless of soil ecosystems. The government should change policies related to agricultural subsidies and grain output.