基于MGWR模型的江苏省耕地细碎度空间格局与驱动因素分析

    Spatial pattern and driving factors of cultivated land fragmentation in Jiangsu Province using MGWR model

    • 摘要: 耕地细碎化通常被认为会降低农业生产效率,进而威胁粮食安全。认知耕地细碎度格局及驱动因素是科学治理耕地细碎化的重要前提。该研究以江苏省为研究区,从斑块密度指数、面积加权平均形状指数、面积多样性指数、斑块结合度指数4个维度评估县级耕地细碎度,并基于K-means方法分析不同维度耕地细碎度的聚类特征。在此基础上,该文应用多尺度地理加权回归模型(multiscale geographically weighted regression,MGWR),从地形部位、土壤性状、城市化水平、利用强度、耕地保护力度5个维度探究了江苏省各县区细碎度的驱动因素。研究结果表明:江苏省耕地呈现南北差异,具体表现为斑块密度与形状指数北低南高,面积多样性指数北高南低,结合度指数西高东低。4个维度的县级耕地细碎度指标表现出3类聚类特征:A类(高连片-小田块类型)和B类(低连片-小田块类型)县区位于省南部,均表现出斑块密度大、形状不规则,面积多样性较高的特征,其中A类县区比B类县区具有更高的耕地连片性;C类(高连片-大田块类型)县区的斑块密度较低,形状规则,面积多样性低且耕地连片度高,主要分布在中部和北部地区。此外,不同类型区域耕地细碎度的驱动因素表现出空间异质性特征,面向不同地区应采取差异化的细碎化治理策略。南部县区(A类和B类)的耕地细碎度主要受自然因素驱动,而中部和北部县区(C类)的耕地细碎度则受到更为复杂的综合因素影响,包括耕地分配制度、经济发展情况等。该研究的结果可为江苏省优化耕地细碎度治理模式,进而发展耕地可持续利用提供参考。

       

      Abstract: Cultivated land fragmentation is often considered to reduce agricultural productivity, leading to threatening food security. The pattern and drivers of cultivated land fragmentation can be expected to serve as an important prerequisite for scientific management. Taking Jiangsu Province as the study area, this study aims to assess the cultivated land fragmentation at the county level from four dimensions, including PD (patch density), AWMSI (area-weighted mean shape index), SHDI-S (Shannon's diversity index of area), and COHESION (patch cohesion index). A systematic analysis was made on the clustering features of cultivated land fragmentation in different dimensions using the K-means. MGWR (multiscale geography weighted regression) model was applied to explore the driving factors of cultivated land fragmentation in each county from five dimensions: topographic site, soil properties, urbanization, utilization intensity, and protection strength. The results showed that there were north-south differences in the cultivated land, where the PD and AWMSI were higher in the south than those in the north, the SHDI-S was higher in the north than in the south, and the COHESION was higher in the west. The four dimensions of the county-level cropland fineness index showed three types of clustering: Type A and Type B counties were located in the southern part of the province, both of which shared high patch density, irregular shape, and high area diversity. Among them, the Type A counties were higher connectivity of cultivated land than Type B; Type C counties shared lower patch density, regular shape, low area diversity, and high cropland connectivity, which were distributed mainly in the central and northern parts of the province. In addition, spatial heterogeneity was observed in the driving factors of cultivated land fragmentation in different types of regions. Differentiated fragmentation management should be adopted for the different regions. Among them, cultivated land fragmentation in the southern counties and districts (Type A and Type B) was mainly driven by natural factors (elevation, slope, and soil capacity). There were the more complex factors in the central and northern counties (Type C), including cropland allocation and urbanization. Cultivated land in the Type A counties exhibited a high density and irregular shape of patches, but a high degree of connectivity, which was a greater potential for management. Some considerations were given to promote the merging of adjacent cultivated land for large-scale production when the soil properties were similar in the topographic conditions. A low degree of contiguous cultivated land was observed in Type B counties, indicating the more complex driving factors are more difficult to manage. More attention should be paid to protecting the existing cultivated land for future urbanization. Cultivated land in Type C counties shared a low density and regular shape of patches, with the large cultivated land and continuous distribution. Cultivated land in Type C counties was the most affected by the topographic slope and protection. The central and northern regions were mainly plains with flat terrain and arable land, indicating the low potential for management. However, some attention should still be paid to regulating the use of cultivated land. The finding can provide a strong reference to managing the cultivated land fragmentation in Jiangsu Province. The cropland fine fragmentation model can also be optimized to develop the sustainable use of cropland.

       

    /

    返回文章
    返回