保护性耕作技术、种植制度与土地生产率——来自黄土高原农户的证据

Conservation tillage,cropping systems and land productivity for households on the Loess Plateau

经济效益是农户采纳保护性耕作技术的关键。本文基于黄土高原小麦玉米种植户的调查,采用扩展的C-D函数模型和多元回归模型分析了不同种植制度下农户保护性耕作技术采用对土地生产率的影响。研究发现:(1)保护性耕作技术对作物产量有显著的正向影响,但其作用的发挥具有缓释性;保护性耕作技术对一年两熟制和两年三熟制农户顷均利润有显著的正向作用,在考虑家庭劳动力投入的机会成本后,顷均利润的效果更明显。(2)种子费用、灌溉费用、机械服务费用对作物产量有正向影响,农药除草剂对作物产量的影响取决于其是预防性的还是控制性的。(3)户主的受教育程度对土地生产率有显著的正向作用;在不计家庭劳动力成本的情况下,农业劳动力规模对顷均利润有正向作用;土地经营规模与作物产量呈正相关关系,而土地的细碎化阻碍了农户顷均利润的增加。

Analysis of the impact of conservation tillage technology on land productivity can provide a reference for developing environment-friendly farming techniques and achieve sustainable agricultural development in the Loess Plateau region of China. Based on a survey of 476 wheat-maize planting households on the Loess Plateau, extended C-D function and multiple regression models were used to analyze the effect of conservation tillage technology on land productivity under different planting systems. We found that conservation tillage technology had a significant positive effect on crop yield, but its effect was slow-release. Conservation tillage technology had a positive effect on the profit of average ha in the area of two croppings per year system and three croppings per two-year system. The effect of conservation tillage on profit was more obvious when the opportunity cost of family labor input was taken into account. Seed costs, irrigation costs and machinery costs had a positive effect on crop yield, and the impact of pesticide and herbicide on crop yield depends on whether they were prophylactic or controlled. The education level of the head of the household had a positive effect on land productivity. Without considering family labor costs, the scale of family agricultural labor had a positive effect on average profit per ha. The scale of land management was positively related to crop yield, while land fragmentation hindered increases in farmers＇ profits. Irrigation convenience was beneficial to increase the profit of average ha in areas of more than one crop a year. Crop yields and profits were higher in flat areas than sloped areas.