西藏县域农作物种植结构时空变化及专业化分区

Spatial evolution and specialization division of crop planting structure in counties of Tibet, China

从农业区域系统的角度分析农作物的空间集聚和专业化,可为农业产业结构调整及优化提供决策依据.以西藏粮食作物、油料作物、蔬菜和饲草4类作物为研究对象,基于1995-2020年西藏农业统计年鉴农作物播种面积数据分析西藏农作物种植面积时序变化,基于1995-2018年统计年鉴农作物播种面积数据和74个县域空间单元,综合运用重心模型、基尼系数、区位熵及空间自相关模型,通过ArcGIS软件分析西藏作物种植空间变化及专业化格局.结果显示:(1)西藏粮食作物种植面积占比历年均占绝对优势,但呈逐年下降趋势,油料作物种植面积整体呈波动性小幅上升,蔬菜和青饲料种植面积逐年明显增长.粮食作物、经济作物(含油料作物和蔬菜)、饲料作物比例从1995年的86:12:2调整到2020年的68:17:14.(2)1995-2015年间西藏粮食和油料生产重心较为稳定,未出现较大范围的地理迁移,其他农作物重心迁移距离较大,从东南向西北迁移416.7 km.(3)西藏农作物均呈现一定程度的空间集聚和区域专业化生产格局,但在研究期内生产集聚及专业化水平呈下降趋势.(4)将西藏粮食、油料和其他农作物划分为绝对优势区、比较优势区、优势衰退区、潜力优势区、不具优势区、优势退出区、可种植区和无种植区8种类型.本研究表明西藏农作物种植结构调整明显,基于生产格局及演变趋势划定了专业化分区,可引导农作物生产布局优化,对有效保障西藏地区粮食安全具有重要意义.(图6表5参26)

The study analyzed the geographical agglomeration and specialization of crops from the perspective of an agricultural regional system with the aim of informing decisions concerning adjustments of the industrial structure of crops in Tibet, China. Based on crop planting area data in the agricultural statistical yearbooks of Tibet from 1995 to 2020, temporal changes of the planting areas of grain crops, oil-bearing crops, vegetables,and green feed were analyzed in 74 counties. Spatial economics gravity and spatial autocorrelation models,specialization index, and geographic information system(GIS) technology were utilized to reveal the evolving trend of crop production space and specialization in Tibet. The analyses revealed(1) a significant adjustment in the internal structure of crop planting industry in Tibet. Grain crop planting area was once dominant, but the ratio of grain crop to total crops has since consistently declined with time. The ratio of the oil-bearing crop planting area fluctuated slightly, and the ratio of vegetables to green planting area increased significantly year by year.The ratio of grain-to-economy-to-feed changed from 86:12:2 in 1995 to 68:17:14 in 2020.(2) The production gravities of grains and vegetables were relatively stable based on the 1995-2018 data. No massive geographical migration was evident. The production gravities of vegetables and green fodder have migrated 416.7 km from the southeast to northwest during the past 21 years.(3) A certain degree of spatial agglomeration and specialization level of crop production in Tibetan counties was evident. However, the production agglomeration and specialization level of crops displayed a downward trend during the study period. Finally,(4) based on the changes in crop planting area, crops in Tibet were divided into eight types of production space: absolute advantage, comparative advantage, advantage recession, potential advantage, non-advantage, advantage exit,plantable, and non-plantable zones. It is of great significance to effectively guarantee food security to delimit production space zones based on the evolution trend of agglomeration of crop production and specialization level, and to guide optimization of land use for crop production.