粮食作物种植视角下东北粮食主产区耕地利用的时空分化特征. (Chinese)

Cultivated land is mostly used to raise crops, and thereby the evaluation of cultivated land use can be expected from the perspective of crop planting, in order to ensure the subsequent refined research of cultivated land use and food security. Taking Baiquan, Keshan and Yi'an county as the research areas, this study aims to extract the spatial distribution information of cultivated land use on major food crops, including maize, soybean, and rice, during the implementation period of national planting structure adjustment policy from 2016 to 2019. Sentinel-2 remote sensing data and random forest classification were used in this study. ArcGIS 10.2 software was selected to achieve the annual crop classification, ranging from dividing various cultivated land into regions, then to counting into the vector map spots of cultivated land. The spatial distribution map of cultivated land use on main grain crops from 2016 to 2019 was obtained with the plot as the statistical unit. Standard deviation ellipse and main center models were used to analyze the quantity and spatial differentiation characteristics of cultivated land use. In addition, the spatial exploratory analysis method was used to explore the spatial correlation of cultivated land use structure in 48 towns. The results show that: 1) During the research period, there was obvious change characteristics of “scissors difference” occurred in the planting area of soybean and maize, whereas, the planting area of rice basically remained stable, indicating the dominated implementation effect of maize reduction policy, while soybean and maize became the main food crops. The proportion of soybean planting in the total cultivated areas increased from 7.18% to 44.94%, whereas the maize planting decreased from 88.19% to less than 50%, and the rice planting remained at about 5% of the total cultivated areas. 2) The spatial distribution of cultivated land use demonstrated a typical dynamic pattern of “from northwest to southeast”. During the study period, the driving force of soybean distribution was strong, whereas the spatial distribution of maize was relatively constant. The main center of cultivated land use on soybean and maize was in the middle east of the study area. The center of land use on soybean crop shifted 27.17 km clockwise from east to south, while the center of land use on maize crop moved 25.52 km anticlockwise from west to south, possibly due to the policy implementation of planting structure adjustment from 2016 to 2019. 3) There was strong positive or negative spatial correlation among the structure variation of cultivated land use on main grain crops in the study areas. The area type of positive correlation mostly occurred in the form of cluster, indicating strong clustering and remarkable regional consistency. In the type of negative correlation, there was no obvious aggregation area, showing small number and sporadic distribution. The findings reveal the quantity and distribution features of major grain crops, particularly on soybean, maize, and rice, indicating the comprehensive situation of cultivated land utilization in the implementation period of planting structure adjustment policy in the study area. This study can provide a promising insightful reference for the regional planting structure adjustment and urban food security in the cultivated land use. Keywords: land use, remote sensing, cultivated land, food security, grain crops, temporal-spatial differentiation, major grain producing of northeast China. [ABSTRACT FROM AUTHOR]

作物种植是耕地最直接的利用方式。基于粮食作物种植视角研究耕地利用问题，是耕地利用领域研究的进一步细化，也是粮食安全的基础。该研究以东北粮食主产区典型地域为研究区，基于主要粮食作物大豆、玉米和水稻的不同耕地利用方式，以乡镇为单元，综合运用标准差椭圆、重心模型及探索性空间数据分析法，阐明2016—2019年研究区粮食作物的耕地利用空间分化特征。结果表明：1）研究区主要粮食作物的耕地利用结构变化明显，大豆与玉米的耕地种植面积出现明显“剪刀差”变化特征，水稻的耕地种植面积基本保持稳定。2）研究区主要粮食作物的耕地利用空间分布呈现“西北-东南”动态格局，种植大豆和玉米的耕地利用重心位于研究区的中东部地区，分别向东偏南和西偏南方向迁移。3）研究区种植主要粮食作物的耕地利用结构具有较强的正负空间关联性，正相关类型聚集性较强，表现出明显的区域一致性；负相关类型无明显聚集区域，面积较小，且零星分布。研究结果较好地反映了种植结构调整政策实施阶段研究区种植主要粮食作物的耕地区域空间布局分化和耕地种植结构的空间关系，为区域种植结构调整及保障粮食结构性安全提供科学依据。 [ABSTRACT FROM AUTHOR]

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