Abstract:

Analytic Hierarchy Process (AHP) method has been widely applied to measure sustainability of agricultural land use by determining the weight of each evaluation factor. Delphi method was often used in existing AHP-based weight calculation of the evaluation factors. Delphi method is built on an expert weighting model and therefore difficult to avoid subjective judgment of experts. In this article, a modified AHP method is proposed to calculate the weight of each evaluation factor using the Grey Relation Analysis (GRA) method to solve the problem in using the Delphi method. Using Zaoyang City, a representative area in agricultural land use in northern Hubei Province, China, as the case study area, an evaluation system of sustainable agriculture land use was first established considering a hierarchy of levels including goals, rules, and criteria. The rule level consists of four aspects: agriculture land output sustainability, resource input sustainability, ecological sustainability, and socioeconomic sustainability. Second, experts chose one characteristic factor at the criterion level for each rule element to constitute reference variable sequence and the other factors in the same rule level to constitute comparative variable sequence in GRA. Third, grey relation coefficients were calculated between the characteristic factor and the other factors in the corresponding comparative variable sequence. In constructing a pairwise comparison matrix, experts gave each factor at criterion level a dominant value between 1 and 9 based on the grey relation coefficients. Then calculations were performed to find the satisfactory maximum Eigen value, consistency index CI, consistency ratio CR, and lastly, vectors of weights for factors at the criterion level were obtained, reflecting the relative importance of the various factors to the goal hierarchy in the AHP. Using the weights resulted from this procedure, sustainability of agricultural land use in Zaoyang City was calculated using a Multi-Objective Liner Functions Comprehensive Evaluation (MOLFCV) model, and the obstacles to sustainable agricultural land use in the city were identified. The results show that the sustainability of comprehensive land use of the city increased from 2001 to 2012 while the ecological sustainability of agriculture land resource use was strongly lower than the socioeconomic sustainability since 2006. The reason directly lies in the increasing use of chemical fertilizers and pesticides and the continual decline of annual precipitation in the farmland area. However, it was the lack of awareness and priority of ecological environment protection in the local agricultural land use that resulted in lower ecological sustainability than economic and social sustainability of agricultural land use in Zaoyang City. Moreover, obstacles for sustainable agriculture land use in Zaoyang City included suboptimal total agricultural output per hectare of land, per capita area of cultivated land, amount of fertilizer applied per hectare of cultivated land, effective irrigated area, annual precipitation, per capita GDP, and net income of rural households.

Key words: agricultural land resourse, sustainability of land use, Analytic Hierarchy Process (AHP), Grey Relation Analysis (GRA), identification of obstacles, Zaoyang City of Hubei Province