延安市农业水土资源匹配及承载力

为客观分析延安市农业水土资源空间匹配状况,根据耕地、水资源量等数据,在分析延安市水土资源空间分布格局的基础上,通过构建洛伦兹曲线以及农业水土资源匹配计算模型,对延安市及其13个区县农业水土资源的匹配程度进行评价。结果表明:延安市农业水土资源匹配系数0.26×104 m3/hm2,匹配程度较差,低于全国同期平均水平0.54×104 m3/hm2,并且空间匹配程度存在明显的差异,总体上呈现出南优北差的匹配格局。在全面分析影响农业水土资源承载力多种因素的基础上,建立延安市农业水土资源承载力评价体系,将粒子群优化算法与投影寻踪模型结合在一起,对延安市各区县农业水土资源承载力进行了评价。结果表明,子长县和延长县农业水土资源承载力最低,承载力IV级;黄龙县农业水土资源承载力最高(II级),其他大部分区县农业水土资源承载力处于中等偏低水平(III级),研究可为提高粮食生产效益及区域农业水土资源可持续利用提供依据。

Agricultural water and soil resources matching patterns and carrying capacity in Yan'an City

Abstract: Yan'an City is located on the loss plateau of Northern Shaanxi Province with severe water and soil erosion problem and poor condition of agricultural production. Water resource shortage and soil erosion have been two of the most important factors that limit the sustainable agricultural development. This study aimed to investigate the spatial matching pattern and carrying capacity of agricultural water and soil resources in Yan'an City. The water-and-soil resources relevant data from 2003 to 2013 were collected. An available water resource was employed to represent water resources. Then the Gini coefficient method based on the Lorenz curve and a model for calculating matching coefficients were constructed to evaluate the matching degree of agricultural water and soil resources of Yan'an City and its 13 administration counties. Additionally, by studying the factors affecting carrying capacity of agricultural water and soil resources, an evaluation system consisted of a target layer, a system layer and an index layer was established. Meanwhile, the Particle Swarm Optimization was adopted to optimize the projection index function and determine the one-dimensional value, and a Projection Pursuit Classification model was constructed to evaluate the agricultural water and soil resources carrying capacity at Yan'an City. The results showed that the Gini coefficient of water and soil resource in Yan'an City was 0.449, indicating the poor matching degree. The matching coefficient of agricultural water and soil resources in Yan'an City was 0.26×104 m3/hm2, which was below average level of Shaanxi Province (0.47×104m3/hm2) and far below the national average level (0.54×104m3/hm2), indicating a poor matching degree as well. The spatial matching pattern of the water and soil resources suggested that the matching degree was higher in South than that in North. Meanwhile, the agricultural water and soil resources carrying capacity of the administration counties in Yan'an City was different greatly, being lowest in Zichang and Yanchang (belonging to the IV level), indicating severe imbalance between socioeconomic development and water-soil resources development in these cities. The carrying capacity of Huanglong County was the highest, which belonged to the II level and indicated that the water-soil resources could satisfy the socioeconomic development, and the carrying capacity of other counties belonged to the III level and presented an imbalance development between social economy and water-soil resources. From this study, it suggested that the water diversion project and the farmland infrastructure project should be made and carried out to improve the basic conditions of agricultural production in these counties of Yan'an.