采用保护性耕作对减少水稻产量损失的实证分析——基于4省1080个稻农的调研数据

干旱和洪涝是造成水稻减产最主要的自然灾害,稻农通过采用保护性耕作可以减少其对水稻的产量损失。基于2013—2015年中国水稻主产区1 080个水稻农户的调研面板数据,论文采用内生转换模型,实证分析了稻农通过采用保护性耕作应对干旱或洪涝的效果,并分别估计了采用者和未采用者的水稻单产情况。实证结果表明:1)采用者的水稻单产远远高于未采用者的水稻单产;2)在反事实假设情况下,如果采用者未采用保护性耕作,其水稻产量将相应减产457.95 kg/hm~2(约7%);如果未采用者采用保护性耕作,其水稻产量将相应增产225 kg/hm~2(约4%);3)户主种植经验、受教育年限和公共服务可得性正向影响稻农的采用行为。最后,论文建议政府应大力推广保护性耕作技术,加大对抗逆水稻品种的培育,加强对农业生产资料的投入和管理,扩大公共服务的覆盖范围。

The Impact of Conservation Tillage on Reduction in Rice Yield Loss:Evidence from 1 080 Chinese Rice Farmers

Droughts and floods have become two kinds of major natural disasters causing rice yield loss. The challenges on food security caused by increasing natural disasters have drawn much attention of researchers. Recent studies have identified a variety of effective adaptation measures taken by farmers to cope with natural disasters. Conservation tillage, considered as one of the main adaptation measures, could help farmers reduce yield loss. A three-year survey of 1 080 Chinese rice farms was conducted in major rice producing provinces in China, Zhejiang and Jiangsu in the coastal area of eastern China, Sichuan in southwest China, and Hunan in central China. Based on the panel survey, we identified the factors influencing farmers’ taking measures of conservation tillage, and evaluated the effectiveness of conservation tillage as a main adaptation measure against droughts and floods. Particularly, the behavior of taking the measure of conservation tillage could be endogenous, which has not been well examined in the literature. Taking into account the endogeneity of the behavior, we employed an endogenous switching regression model to estimate the effects of whether or not taking the measure of conservation tillage. The results revealed that the coefficients of droughts and floods for taking the measure of conservation tillage are 0.099 and 0.315 respectively, and both are statistically significant. It is consistent to our common sense that rice farmers are more likely to take the measure of conservation tillage when they have suffered from droughts and floods. Besides, whether farmers take the measure of conservation tillage also depends on labor cost, local access to public services for coping with droughts and floods, the tolerant variety of rice, agricultural labor forces, famers experience on rice production and soil quality. The former four factors can encourage farmers to take the measure of conservation tillage, while more experience on rice production and better soil quality discourage farmers to take the measure of conservation tillage. Moreover, we found that taking the measure of conservation tillage increased the yield by 457.95 kg/hm² (about 7%). In contrast, the farmers who did not take the measure would increase the rice yield by 225 kg/hm² (about 4%) if they take the measure. These findings suggest conversation tillage does increase the rice production and help reduce the rice yield loss caused by drought and floods. It also indicates that the possible benefit for those who have not taken the measure of conservation tillage is much smaller than the benefit for those who have already taken the measure.