喀斯特生态脆弱区休耕地的空间配置研究——以贵州省晴隆县为例

实行耕地轮作休耕不仅是促进耕地休养生息、加快生态文明建设的重要任务,也是提高农业供给体系质量、实现农业与社会经济可持续发展的重要途径。本文从喀斯特生态脆弱区的人地关系特点出发,围绕休耕的目标导向及约束条件,厘定休耕地空间配置的逻辑内涵,在此基础上以国家休耕试点县——贵州省晴隆县为例,综合运用VSD脆弱性评估框架、灰色预测模型GM（1, 1）和GIS空间分析等方法,通过休耕地初判、休耕地修正、休耕地优选三个步骤实现休耕地的分区布局,据此探讨喀斯特生态脆弱区休耕地空间配置的实现路径与技术方法。结果表明：① 晴隆县耕地生态系统脆弱性较强,全县70%以上的耕地非常脆弱甚至极度脆弱,急需优化耕地利用方式,促进耕地生态修复。② 以粮食安全约束下的耕地保有量作为休耕规模的约束条件,依据耕地生态系统脆弱性由大到小进行筛选,得出晴隆县2015-2020年可休耕耕地规模共计13540.05 hm²,占全县耕地面积的37.18%。③ 根据休耕规模、耕地质量、地形地貌、交通区位、社会经济发展水平等方面的差异,晴隆县休耕地可按“三级五类”进行分区布局,具体布局休耕项目时要因地制宜,制定差异化的休耕模式及休耕组织方式。④ 休耕地的空间配置是一个“对象”和“规模”双重约束下的休耕地块优选问题,在此过程中,休耕对象诊断是基础,规模预测是约束,休耕项目布局是最终落脚点。

Spatial allocation of fallow land in karst rocky desertification areas: A case study in Qinglong County,Guizhou Province

Fallow is important to promote the recuperation of cultivated land and enhance the sustainable development of agriculture and society. To examine the direction of fallow, this paper developed a conceptual framework and logical process to select fallow regions. First, the fallow regions were selected by diagnosing the cultivated land vulnerability using the VSD model, grey GM(1, 1) model and GIS spatial analysis methods. Second, the fallow scales were revised based on the restriction of cultivated land quantity. Third, the fallow regions were determined in ecological vulnerable karst areas. The results indicate that: (1) The farmland ecosystem in Qinglong County is in quite a dire state, with more than 70% of arable land in the county classified as very vulnerable or extremely vulnerable. Improvement of the land use pattern through fallowing is urgently needed to promote restoration of the ecosystem. (2) Under the constraints of food security, the fallow areas reach 13540.05 ha in the period of 2015-2020, or 37.18% of cultivated land in the county. (3) According to the fallow area, quality, landforms, and location of cultivated land and socioeconomic development levels, the fallow regions in Qinglong can be divided into three "grades" and five "types", which can be converted to the fallow land in the future. The implementation of fallow policies should consider the local conditions, so as to formulate different fallow modes and organizational form. (4) The fallow region-selecting is an optimizing process of fallow based on the two constraints of "object" and "scale". In the process, identification is the base, scale prediction is the constraint and implementation of fallow project is the final product.