作物种植专业化与化肥减量来源——兼顾经营规模的影响

以作物种植横向专业化和纵向专业化为切入点,运用中国13个粮食主产省份1980—2018年的面板数据,考察了作物种植专业化对农业化肥减量的影响及其作用机制。研究主要发现：（1）基础回归分析表明,作物种植横向专业化和纵向专业化均对化肥施用强度具有显著的削减效应,对化肥的利用效率有显著的增效作用。且作物种植纵向专业化或社会化服务卷入程度加深,能够增强横向专业化对化肥的减量增效作用。（2）影响路径分析表明,作物种植横向专业化通过扩大农地经营规模,进而增强了作物种植纵向专业化对化肥施用强度的削减效应和利用效率的增效作用。但也应警惕,通过扩大农地经营规模以增强作物种植纵向专业化的减量效应可能存在临界水平。此外,当作物种植横向专业化和纵向专业化积极配合时,可能推移临界点的到来。据此,通过发展作物种植横向专业化,鼓励农户通过服务外包卷入农业的纵向专业化分工以及发展农业适度规模经营,进而实现农业领域化肥的减量增效。

Crop specialization and chemical fertilizer reduction: The pathway of operation scale

This paper analyses the effects of crop specialization on the fertilizer reduction from two dimensions, horizontal crop specialization and vertical division of agricultural production process (vertical specialization). Based on the panel data of 13 major grain producing provinces in China from 1980 to 2018, the effect of crop planting specialization on the reduction of agricultural chemical fertilizer and its mechanism were investigated. The results indicate that, first of all, with the development of horizontal and vertical specialization the fertilizer application intensity reduces and the fertilizer use efficiency increases. The deepening in vertical specialization would enhance the positive effects of expanding horizontal specialization on fertilizer reduction. Secondly, the crop specialization may reduce the fertilizer via two pathways. Pathway 1 is that the increasing horizontal specialization could increase farm operation scale, which contributes to fertilizer reduction. Pathway 2 is that the increasing of horizontal specialization could increase farm operation scale, which further enhances the positive effects of vertical specialization on reduction. However, there is an optimal value for the proper operation scale, and it would be increased with deeper merger of horizontal and vertical specialization. Therefore, it is of great importance to encourage the horizontal and vertical specialization to reduce chemical fertilizer application. It is critical to inspire farmers to expend the operation scale and then further promote the reduction of fertilizer use.