基于耕地能值-生态足迹的耕地休耕规模研究——以贵州省松桃县为例

Abstract

区域耕地休耕规模测算是耕地休耕空间配置的重要组成部分，从资源承载力视角理解，其本质是将休耕空间布局于耕地资源承载力相对较低的区域。立足于从区域耕地生态经济系统探索耕地休耕规模，运用能值分析方法和生态足迹方法，以生态严重退化地区、国家第一批休耕试点县的贵州省松桃县为案例区，修正了耕地能值生态足迹改进模型（EC和EF，简称"修正模型"）与耕地能值可持续指数（ESI_cl），测算了松桃县2016年休耕面积范围值。结果表明：（1）耕地能值生态盈亏可以作为乡镇是否应该休耕的判定标准，基于此测算的最大休耕面积关键在于测算生态耕地面积。总体来看，全县耕地能值生态赤字，应该安排耕地休耕；从分乡镇来看，有3个乡镇可以不休耕、25个乡镇应该休耕。按照全县平均统计（SCAL）和按照分乡镇统计（STL），全县最大休耕面积分别19558.62hm²和17673.83hm²。最大休耕面积中等及以上等级的乡镇散布于4个区域的8个乡镇。（2）ESI_cl可以作为休耕乡镇时序的判定标准，其优先休耕乡镇的最大休耕面积之和即为全县最小休耕面积。全县ESI_cl偏低，应该适度休耕。优先休耕、适度休耕和暂不休耕的乡镇分别有2个、23个和3个。全县最小休耕面积1396.10hm²，占耕地面积的1.88%。按照全县平均统计（SCAL），全县休耕面积范围值1396.10-19558.62hm²，占总耕地面积的1.88%-26.34%；按照分乡镇统计（STL），全县休耕面积1396.10-17673.83hm²，占总耕地面积的1.88%-23.8%。修正模型和ESI_cl为测算区域休耕规模提供了更加科学的技术方法，以期为其他类似区域开展休耕实践提供借鉴。;The scale calculation for regional cultivated land fallow is an important part of the spatial allocation of the cultivated land fallow. The essence of the scale calculation is the arrangement of regional fallow space to the area of relatively low carrying capacity of the cultivated land resource in the perspective of resource carrying capacity. Based on the exploration of cultivated land fallow scale from the regional cultivated land ecological economic system, this paper selected Songtao County of Guizhou Province of the first batch of national fallow pilot counties,and this county is also a serious ecological degradation area. We applied emergy analysis and ecological footprint method to revise the improved model for the cultivated land emergy ecological footprint (EC and EF, referred to as the modified model) and the emergy sustainability index of the cultivated land (ESI_cl) for calculating the fallow area value of Songtao County in 2016. The results demonstrated that firstly, the ecological profit and loss of the cultivated land emergy can be used as a criterion for determining whether a township should be lay fallow by calculating the maximum value of fallow cultivated land area, especially for calculation of ecologically cultivated land area. Because ecological deficit of the cultivated land emergy in Songtao County has been determined by calculating ecological profit and loss of the cultivated land emergy, the cultivated land should be lay fallow totally. What's more, there are 25 townships in Songtao County, which should be lay fallow except for 3 townships. According to the statistic of county's average level (SCAL) and the statistic township level (STL), the largest fallow area is 19558.62hm² and 17673.83hm², respectively. Townships with the largest fallow area of more than medium grade are scattered in 8 townships. Secondly, ESI_cl can be used as the criterion for determining the time sequence of fallow townships. The sum of the maximum fallow area of the priority fallow townships is the minimum fallow area. Because the ESI_cl is low, the cultivated land should be moderately lay fallow in Songtao County. There are 2, 23 and 3 townships should be on priority fallow, moderate fallow, and temporary non-fallow, respectively. The smallest fallow area is 1396.10 hm² in the county, accounting for 1.88% of the cultivated land area. According to the SCAL, the range value of fallow area of Songtao County is 1396.10-19558.62hm², accounting for 1.88%-26.34% of the total cultivated land area; according to the STL, the range value of fallow area of Songtao County is 1396.10-17673.83hm², accounting for 1.88%-23.8% of the total cultivated land area. The modified model and ESI_cl provide a more scientific technical method for calculating the regional fallow area. It is expected to provide a reference for other similar regions to carry out cultivated land fallow practices.