中国粮食生产环境效率及其影响因素分析

近年来,农业生产带来的环境问题引起日益广泛的关注,而测算环境效率能直观反映农业生产对生态环境的影响,使人们清楚地认识到农业生产所付出的环境代价,进而推动中国农业生产向更具可持续性的方向转变。有鉴于此,本文基于2004-2012年全国农村固定观察点数据,采用超越对数随机前沿分析方法测算了中国农户粮食生产的环境效率,并用Tobit模型考察农户粮食生产环境效率的影响因素。研究结果表明：①全国范围内农户粮食生产的技术效率与环境效率均值分别为0.802和0.489,并且两种效率之间具有较高的相关性;②考虑环境效率后,中国粮食生产的技术效率均值出现了略微的下降趋势,但东部、中部、西部依次递减的趋势没有改变;③环境效率地区间差异明显,呈现出中部、西部、东部依次递减的趋势。而且随着时间变化,各地区的环境效率均呈现出递减趋势;④不同规模农户的粮食生产环境效率也存在差异,具体而言,大规模农户粮食生产环境效率普遍高于中小规模农户;⑤农户特征、农业生产要素、农业技术培训以及土地细碎化等因素均会影响粮食生产环境效率。

Environmental efficiency and its determinants regarding China's grain production

Environmental issues caused by agricultural production have attracted wide concern. Estimating environmental efficiency is an intuitive way to reflect the impact of agricultural production on ecological systems,which can make people realize the environmental costs of agricultural production and contribute to sustainable production. We used the Rural Fixed Point Observation（RFPO）dataset from 2004 to 2012 for China and adopted a stochastic frontier translog production function to estimate the environmental efficiency of China’s household grain production. A Tobit model was then used to identify the determinants of environmental efficiency. We found that the average technical efficiency and environmental efficiency are 0.802 and 0.489 respectively. A strong and positive association was also detected between these two efficiencies. The estimated average technical efficiency dropped slightly after taking environmental efficiency into account,while the relative magnitude of technical efficiency in three regions remains the same. We found that environmental efficiency varies greatly across regions and Central China has the highest efficiency while Eastern China the lowest. A decreasing trend along with time change in environmental efficiency was found for all three regions,indicating a deteriorating agricultural ecological system in China. Farmers with different scales also presented different environmental efficiency. Large-scale farmer’s environmental efficiency is higher than small-scale farmers. Environmental efficiency was also influenced by farmer characteristics,agricultural inputs,training and land fragmentation. In particular,older and well-educated farmers have higher environmental efficiency;larger scale farms and more labor input also contributed to lower pollution. Agricultural training,land fragmentation,and intensive use of fertilizers and pesticides have negative impacts on environmental efficiency.