基于农户微观视角下的大城市郊区耕地土壤质量变化驱动机制研究

对耕地土壤质量变化驱动机制的研究是破解耕地质量变化规律及其效应的关键。利用野外采样与实验室分析相结合、统计分析和计量经济模型等分析方法,对研究区域238 个耕地地块的土壤采样数据和对应农户调查数据进行实证研究,结果表明,不同区域农户土地利用方式、程度和投入强度对耕地土壤质量的作用方向、影响程度和显著水平都不同。其中近郊区的农户“以兼业为主,以农为辅”,其行为突出表现为劳动力投入的“非农化”趋势,对耕地的粗放利用和掠夺式经营现象比较普遍,主要影响因素土地利用程度每增加一个单位,导致耕地土壤的碱解氮、速效磷和速效钾的含量平均下降11.496、44.078 和15.469 mg/kg;研究区域中部农户“以兼业为主”,突出表现为集约化程度比近郊区农户有所提高、种植结构也不断调整,对土地的投入、管理都得到很大的提高,主要影响因素土地利用方式转变会促使土壤有机质、碱解氮、速效磷和速效钾含量平均提高4.799 g/kg、7.454 mg/kg、100.170 mg/kg 和61.205 mg/kg;远郊区的农户“以农为主”,突出表现为“非粮化”趋势,由于比较高的就业机会成本,种地收入超过农户预期,耕地集约化、规模化程度较高,主要影响因素土地投入强度每增加一单位,土壤碱解氮、速效磷和速效钾含量平均增加0.007、0.025 和0.037 mg/kg。基于以上的研究结果,从提高农业生产比较效益、稳定农村土地承包关系和促进土地适度规模经营等方面提出规范农户土地利用行为,改善区域耕地土壤质量的政策建议。

Analyzing the Soil Quality Change Mechanism of the Cultivated Land Based on the Microscopic Perspective of the Household in the Metropolitan Suburban

Researching the mechanism of the soil quality change of cultivated land is the key to know the rules of the soil quality change and its effect. Combining the field sampling and laboratory data, and on the basis of statistical analysis and econometric models analysis, a case study of 238 households and the corresponding plot sampling data in Linhu Street, Wanggangpu Village and Yongle Village, Sujiatun District, Shenyang City was conducted. The results showed that the manner, degree and intensity of land use behavior have different levels of effects on the soil quality of cultivated land. In suburb, the labor input shows outstanding trend of non-farm, so the extensive and predatory use of cultivated land is relatively common, which leads to contend of available nitrogen, available phosphorus and available phosphorus in soil being decreased at the rate of 11.496 mg/kg, 44.078 mg/kg and 15.469 mg/kg. In the outer suburbs, the outstanding performance of the land use is plating economic crops. Because of the relatively high cost of employment opportunities, the income of farming is more than the expect of the household. the intensification of cultivated land, the degree of land-scale operation is higher in this area. Every unit increase of land investment intensity leads to the nitrogen, phosphorus and potassium content in soil increasing 0.007 mg/kg, 0.025 mg/kg and 0.037 mg/kg on average. In the middle of the two areas, the outstanding performance of the land use is increasing the land input and adjusting the planting structure. The land use change will lead to the increase of soil organic matter, nitrogen, phosphorus and potassium content at an average of 4.799 g/kg, 7.454 mg/kg, 100.170 mg/kg and 61.205 mg/kg. Based on the above findings, the government could regulate land use behavior by increasing comparative efficiency of agricultural production, stabilizing rural land contract relations and promoting appropriate scale operation of land to improve the soil quality of cultivated land.