基于空间自相关的耕地质量空间分布特征研究——以江西省南昌县为例

Spatial distribution features of cultivated land quality based on spatial autocorrelation:A case study of Nanchang County,Jiangxi Province

为了掌握与分析耕地质量空间分布特征,加强耕地质量建设,完善耕地保护新格局,基于加权平均法、集中度指数、分形维数和空间自相关分析法,以耕地质量等别监测试点县——南昌县为研究区,引入国家自然等指数、利用等指数和经济等指数为空间变量,以耕地图斑为空间单元进行空间自相关分析,从县级和乡镇级尺度上探讨耕地质量的空间差异特征。结果表明,南昌县耕地质量呈现出西南高东北低的空间分布规律,耕地质量等指数Moran's I值表现为自然等指数>经济等指数>利用等指数。不同空间尺度下,耕地质量指数具有不同的空间关联度,自然等指数受空间尺度的影响最大,经济等指数其次,利用等指数最小。正相关HH型和LL型耕地以组团形式聚集分布,负相关HL型和LH型耕地则多以零星状分布。综合考虑南昌县耕地质量空间自相关类型,将耕地划分为常规监测区、综合监测区和重点监测区3个监测分区。研究结果可为区域耕地质量监测、主导限制型谱序、耕地保护与管理分区和空间优化布局等提供借鉴参考。

In order to understand and analyze the spatial characteristics of cultivated land quality,and to improve thequality of cultivated land construction and the new pattern of cultivated land protection,weighted average method,the index of concentration,fractal dimension and spatial autocorrelation analysis were adopted in the present study,and Nanchang County was selected as the study area to explore the differences of spatial characteristics of cultivated land quality from county and township-level scales by introducing the land natural grade index,use grade index and economical grade index as space variables and taking map spot of cultivated land as unit of spatial autocorrelation analysis.It was shown that the cultivated land quality index was high in southwest and low in northeast in Nanchang County.The Moran＇s I value decreased as land natural grade indexeconomical grade indexuse grade index.Different types of cultivated land quality index had different spatial correlation under different spatial scales,and the influence spatial scales on land index decreased as land natural indexeconomical grade indexuse grade index.The positive spatial autocorrelation of cultivated land which contained the High-High type and the Low-Low type emerged as the shape of cluster and had a powerful agglomeration in the form of group,while the negative spatial autocorrelation which included the High-Low type and Low-High type was fragmentary in distribution.Considering the spatial autocorrelation type of cultivated land quality in Nanchang County,the cultivated land was divided into 3 monitoring division,i.e.regular monitoring region,comprehensive monitoring region and key monitoring region.These findings would provide references for the monitoring of regional cultivated land quality,the determination of dominant limiting type order,protection of cultivated land and management of partition,quality improvement and optimization of the spatial allocation of land.