东北黑土区典型县域种植模式遥感识别与空间格局分析

Remote sensing extraction and spatial pattern analysis of cropping patterns in black soil region of Northeast China at county level

种植模式对黑土地的土壤肥力和作物产量有显著影响,建立合理的种植模式是养好用好黑土地的重要措施。目前,黑土区种植模式的类型及其空间格局仍缺乏系统分析,遥感技术结合地学信息图谱方法是监测黑土区种植模式的有效手段,但应用较少。该研究基于2012-2017年遥感反演作物分类数据,采用地学信息图谱方法识别种植模式,并使用核密度分析方法测度各类种植模式的空间分布特征。结果表明:1)克东县可识别出5类种植模式,其中,主要的种植模式为无序种植模式、大豆连作模式和两年轮作模式,三者面积总和占比为83.90%。2)县域西部和北部以大豆连作模式为主,县域中部、东部和南部以无序种植模式为主,玉米连作模式呈东北-西南向带状分布,三年轮作模式和两年轮作模式呈“局部集聚、全局分散”的分布形态。3)行政村尺度的种植模式结构大体可以分为5种类型,总体呈现以“无序种植-大豆连作-两年轮作”类型为主并以其他类型为辅的空间结构特征,属于主要类型的行政村数量占比为32.08%。

Cropping patterns play a significant role in soil fertility and crop production in the black soil region of Northeast China.It is highly demanding for reasonable cropping patterns to make full use of black soil sources at present.However,it is still lacking in a systematic analysis related to the types and spatial distribution of cropping patterns in black soil areas.Taking Kedong County of Heilongjiang Province in China as the research area,this study aims to determine the remote sensing extraction and spatial county-level cropping patterns in the black soil region,particularly on combining with Geo-information Tupu.The specific procedure was as follows.Firstly,the extraction of crop distribution over six years was realized in ENVI software using the Landsat 8 OLI remote sensing images of six phases from 2012 to 2017.Then,the information Tupu of crop change was obtained using the space superposition function of GIS,where the crop change was classified to identify the types and areas of cropping patterns.Finally,the kernel density estimation was utilized to determine the spatial agglomeration of cropping patterns,while the spatial structure characteristics were calculated for the proportion of cropping patterns in each administrative village.The results show that:1)The total planting area of soybean and maize exceeded 94%in Kedong County from 2012 to 2017,indicating the changing trend of“decreasing first before increasing”and“increasing first before decreasing”.There were also relatively low and stable acreages and variations of rice and other crops.2)Five cropping patterns were identified,and then sorted by the area from large to small as follows:disordered,soybean continuous,two-year crop rotation,maize continuous,and three-year crop rotation cropping pattern.Among them,the first three cropping patterns accounted for the largest sum of 83.90%.3)The soybean continuous cropping pattern presented an obvious trend in the west and north county,while,the disordered cropping pattern was distributed in the central,east,and south county.The maize continuous cropping pattern was distributed in the northeast-southwest belt,while,the three-and two-year crop rotation pattern showed the distribution patterns of“local aggregation and global dispersion”.4)The cropping patterns at the administrative village scale were roughly divided into five types,among which“disordered cropping-soybean continuous cropping-two-year crop rotation”dominated,and widely distributed in the northwest-southeast county.Followed by“soybean continuous cropping-disordered cropping-two-year crop rotation”and“disordered cropping-maize continuous cropping-two-year crop rotation”,the former was scattered in the eastern county,and the latter was distributed in the northeast-southwest belt.The administrative villages with the patterns of“disordered cropping-two-year crop rotation-soybean continuous cropping”and“disordered cropping-two-year crop rotation-maize continuous cropping”were scattered in the east and southeast county.