青藏高原粮食生产、消费及安全风险格局变化

Spatial patterns and their changes of grain production, grain consumption and grain security in the Tibetan Plateau

青藏高原是中国粮食短缺地区之一,提高其粮食自给能力和确保粮食安全一直受到中央和地方政府的高度重视。在修订牧业区和半农半牧地区人均粮食消费需求量标准的基础上,利用1985-2015年青藏高原县级行政单元粮食产量和消费数据,采用波动系数法、分级法、重心模型以及粮食短缺指数模型,分析青藏高原粮食生产和消费的时空变化特征,并评估114个县市的粮食安全风险状况。结果表明:青藏高原粮食生产与消费空间分布不均衡,粮食生产呈环形分布在青藏高原东部湟黄谷地、藏东和藏南沿江河谷地带,中部和西部粮食产量较低,粮食消费呈东高西低格局;本地粮食生产不能满足居民消费需求,区域粮食缺口量达21.04万～121.69万t,相当于粮食消费需求的8.22%～40.11%,考虑旅游人口的影响,2015年区域粮食缺口达132.92万t;青藏高原粮食安全风险较高的地区广泛分布在藏北高原、青南高原、祁连山地以及城市化水平较高的拉萨市辖区和西宁市辖区,旅游业发展对林芝市的粮食安全风险影响显著;单纯依靠粮食增产不能解决区域粮食问题,建立完善的粮食储备和交通物流体系、加强与内地及周边国家的粮食贸易合作,是保障青藏高原粮食安全的关键。

The problem of grain shortages has long plagued the Tibetan Plateau,therefore both the state and the local government are scaling up efforts to achieve grain self-sufficiency and grain security in this region.Meanwhile,many researchers devoted themselves to study the grain security issues to provide rational advices.Here in this paper,we intended to analyze the temporal and spatial characteristics of grain production and consumption in the Tibetan Plateau and then evaluate the risk status of grain security in 114 counties.First,we revised the standards of per capita grain consumption demand in pasturing area and farming-pastoral region.Then,on this basis,we analyzed the corresponding data of the 114 counties during1985-2015 by applying the fluctuation coefficient method,classification method,barycenter model and the index model of grain shortages.Analytical results showed that there was a nonuniform geographical distribution of grain production and consumption,moreover,the holistic status of grain security in the Tibetan Plateau was not optimistic.(1)The production of grain increased in fluctuation and the consumption of grain grew steadily,the local grain production could not meet the consumption demand,and the deficit amounts were between 0.21 and 1.22 million tons annually,which accounted for between 8.22%and 40.11%of the grain consumption.The gap between grain production and consumption including tourists increased to 1.33 million tons in 2015.(2)The spatial distributions of grain production and grain consumption in the Tibetan Plateau were imbalanced,the grain yields in Huang-Huang valley and the valley along the Yarlung Zangbo River were higher,while the yields distributed in the central and western parts of the plateau were lower.Affected by population,city,and traffic distribution,the grain consumption was high in the eastern part and low in the western.(3)The spatial patterns of grain security in the Tibetan Plateau in 2015 showed that the higher-risk types involved 42 counties with a population of 2.92 million,and they were widely distributed in western Tibet,northern Tibet,southern Qinghai,Qilian Mountains,as well as in municipal districts of cities of Lhasa and Xining;compared to 1985,the risks of grain security on the midstream and downstream of Yarlung Zangbo River and southeastern Qinghai province were mitigated,while those in western Ngari and northeastern Qinghai were intensified.(4)The tourists increased the risks of grain security in Lhasa,Nyingchi,Shannan,Shigatse,Haidong and Hainan cities,and the negative influence of tourist on Linzhi city was most significant.(5)Production increase alone cannot solve the problem of grain shortage,so it is urgent for the Tibetan Plateau to improve the grain reserves,transportation facilities and expand the grain trade with other regions to achieve regional grain security.