基于局部空间自相关的高标准基本农田建设分区

Zoning of high standard farmland construction based on local indicators of spatial association

加快高标准基本农田建设是实现中国耕地质量保护与管理的有效措施之一。为合理划定高标准基本农田建设区域,该文以广宁县为例,在综合评价耕地质量的基础上,引入局部空间自相关分析(LISA,local indicators of spatial association)进行相关研究。结果表明:广宁县耕地质量整体平均水平较高;村级耕地质量在分布上存在一定的空间正自相关性;根据局部空间自相关结果可将全县分为高标准基本农田建设优化区域、重点区域、后备区域和一般区域。在未来整治与建设过程中,可结合不同自相关类型的特点,针对不同的建设区域采取差别化开发整治措施和有序性建设时序安排。该研究综合考虑了耕地自然属性、社会经济属性以及空间属性的差异,体现出耕地规模、质量与空间聚集"三位一体"的分区保护思路,能够为耕地保护和农田整治建设提供依据。

How to define or partition the actual construction areas is an important research subject. Zoning of high standard farmland construction is not merely a process of quantitative analysis; the natural, economic, social and spatial attributes of farmland should all should be taken into account. In this paper, we tried to improve the rationality of zoning for high standard farmland construction by the spatial structural characteristics of farmland, and by exploring the new zoning method which designated the construction area through spatial analysis. Taking Guangning county in Guangdong Province as a case study, the whole process of the study was composed of three steps: 1) evaluating the quality of farmland comprehensively at map-spot level, 2) taking the result of evaluation at map-spot level as the spatial variation, and exploring the spatial distribution attribute in scale of village through the introducing of Local Indicators of spatial Association, and 3) partition the construction areas according to the results of LISA. The results show that the overall average level of farmland quality in Guangning was relatively high, the high score of map-spots mainly located in the southeast of county, while the low score map-spots spread at the north and southwest. Four classes can be distinguished for better comparable recognizing, and the quality of four classes which contained the first-order, second-order and third-order were about 4366.01, 14796.25 and 3352.96 hm2, respectively. The first-order was the best and the third-order was the lowest comparatively. Moreover, a relatively strong spatial autocorrelation existed among the distribution of farmland quality in Guangning in scale of village, and the positive autocorrelation was superior than passive autocorrelation. In detail, 75.96% of villages had positive autocorrelation which contained the High-High type and Low-Low type(the High-High type meant the village with higher farmland quality was surrounded by villages with same higher farmland quality, in contrast, the Low-Low type indicated the villages with lower farmland quality located together), and 24.04% of them appeared passive autocorrelation which contained the High-Low type and Low-High type(the High-Low type signified the villages with lower farmland quality surround the village with higher quality, and on the contrary the Low-High type meant the villages with higher farmland quality surrounded the village with lower quality). The distribution of spatial autocorrelation types in village level was basically identical with the map-spot of farmland. About 86.34% of first-order farmland shared the same spatial location with the High-High type, while 51.54% of third-order farmland located in the distribution of Low-Low type. In addition, a rational zoning scheme arose by splitting the county into four regions, which comprised of the optimization region, key region, reserve region and general region. These were consistent with the results of spatial autocorrelation. The optimization region mainly located in 'Hengshan-Nanjie-Paisha' groups, the key region mainly consisted of the 'Binheng-Hengshan', 'Luogang-Jiangtun' and 'Shizui-Muge' groups, the reserve region approximately located around the key-region distribution, while the 'Beishi-Chikeng-Kengkou-Gushui' group was the typical spreading area for general region. Various kinds of improved and reclaimed measures for farmland protection can be adopted according to different regions or diverse types of spatial autocorrelation. Based on the results showed above, conclusions included that the local indicator of spatial association was an effective method and can reveal the agglomerate features of farmland. On the other hand, the zoning scheme reflected the three-in-one protecting conception by taking the spatial agglomeration into account. The quantity, quality and agglomerate attributes of farmland can be combined together preferably. The paper introduced a new perspective for farmland protection and reclamation.