西藏小麦生产的时空格局及影响因素

Spatiotemporal patterns and other impacting factors on wheat production of Tibet, China

小麦是西藏第二大粮食作物,种植业结构调整对西藏小麦生产格局影响明显,对西藏粮食安全及粮食供需平衡产生潜在影响.为向西藏小麦科学规划管理决策和高效生产提供依据,以西藏的74个县域单元为研究对象,基于1990-2020年小麦产量,运用区位基尼系数、重心迁移模型、优势指数、莫兰指数和地理加权回归模型,分析西藏小麦生产的时空变化规律及影响因素.结果表明:(1)西藏小麦总产量在1990-1999年呈上升趋势,之后至2020年呈波动性下降,产区主要集中在藏南河谷和藏东三江流域的县域;(2)西藏小麦空间分布格局集聚状况较稳定,生产重心31年间由西向东波动小幅迁移;(3)基于综合比较优势的西藏小麦生产优势区、稍优势区、稍弱势区、弱势区县域占比分别为13.5%、8.1%、9.5%和40.5%;综合比较优势区域分布存在空间集聚现象而非散发分布,区域聚类分布模式为HH(高高)、LH(低高)和随机分布类型;热点区域29个主要分布在拉萨、山南和林芝地区,冷点区域主要分布在日喀则和阿里地区;(4)西藏小麦生产的影响因素较多,其中有效灌溉面积和机械总动力是主要正向因素,地区农业生产总值是主要负向因素,此外,降雨量、其他粮食产量、年末牲畜存栏量、乡村非第一产业从业人口数也对小麦生产有一定影响.总之,西藏小麦种植面积近年呈衰减态势,集聚格局明显,农田灌溉条件、机械化程度和当地经济发展水平均对小麦生产有影响;建议对小麦高产区通过保护耕地、完善灌溉条件、增大机械投入,以高产区集聚县域为依托,因地制宜打造西藏农牧民本地小麦消费的支柱生产基地.(图8表5参30)

Wheat is the second-largest food crop in Tibet, China. Along with economic development, the pattern of wheat production in Tibet has changed dramatically, potentially affecting the balance of grain supply and demand, as well as food security. A clear understanding of the spatiotemporal patterns and other factors affecting wheat production can provide a necessary basis for the scientific management and efficient production of wheat. Based on the wheat yield from 1990 to 2020 in 74 county-level units of Tibet, this study analyzed the spatial and temporal change patterns of Tibetan wheat production and its impacting factors using the Gini coefficient, center of gravity move method, advantage index, exploratory spatial data analysis(ESDA),and geographically weighted regression model(GWR). Results showed that:(1) the total wheat production in Tibet rose from 1990 to 1999, fluctuated, and then decreased from 1999 to 2020. The production areas are mainly concentrated in the southern Tibetan Valley and counties in the Three Rivers region of eastern Tibet.(2) The spatial distribution and agglomeration pattern of wheat in Tibet is relatively stable, and the production center shows a slight fluctuation trend from west to east during the 1990-2020 time period.(3) Based on the comprehensive advantage index(CAI), Tibet’s wheat production in advantaged areas, slightly advantaged areas, slightly disadvantaged areas, and disadvantaged areas accounted for 13.5%, 8.1%, 9.5%, and 40.5% of the total production, respectively;indicating that the regional distribution of CAI exhibits spatial agglomeration rather than sporadic distribution. The patterns are HH(high-high), LH(low-high), and random;29 hot spots are mainly distributed in Lhasa, Shannan, and Nyingchi, while the cold spots are mainly distributed in Xigazê and Ngari;and(4) the impacting factors on Tibet’s wheat production mainly include effective irrigation areas and agricultural mechanization level as positive factors, and regional gross agricultural product as the main negative factor. In addition, rainfall, other grain output, livestock inventory at the end of the year, and the number of nonprimary industries also have an impact on wheat production. Wheat planting area in Tibet has been declining in recent years, thus exhibiting a significant pattern of spatial agglomeration. The three dominant factors affecting the emerging spatiotemporal pattern of wheat production in Tibet are the irrigation condition, mechanization, and local economic development levels. Based on the above conclusions, the study suggests building a high-yield wheat area consistent with local conditions by strictly protecting arable land, improving irrigation conditions, and increasing machinery investment. Depending on the counties of high-yield areas, Tibetan farmers and herders should cultivate the bases of wheat production and build a wheat base for local wheat consumption.