Contribution Factors to Grain Production Increase Based on Gravity Center Model and LMDI Model in Beijing-Tianjin-Hebei Region From 1990 to 2010
利用重心模型和对数平均权重分解法，分析了1990-2010年京津冀地区粮食产量的时空变化，发现单产是增产主因，小麦和玉米贡献最大，为制定农业政策提供参考。
The purpose of this paper is to reveal spatio-temporal variation of grain production and to identify contributing factors for grain increment in Beijing-Tianjin-Hebei region,which will help to make a correct agriculture policy for improving the grain production capacity. The logarithmic mean weigh division index method(LMDI) and gravity center mode are adopted. The results show that: 1 grain production increases by 5.21 million t from 1990 to 2010. It is estimated that the accumulated contributions of grain sowing area and grain yield per hectare at region scale are-3.32 million t and 8.53 million t,respectively. Grain yield per hectare is the major contributor to the increment of grain production. 2The gravity center of grain production and grain sowing area distribution at county level in Beijing-TianjinHebei region are both expressed as move to western and southern regions and the increase of grain production is mainly from wheat and maize. Wheat yield per hectare,maize yield per hectare and maize sowing area are the top three crop contributors. 3 There are obvious differences among accumulated effects of the ten factors at county level. Overall,wheat yield per hectare and wheat sowing area result in remarkable grain increment in middle and south Hebei province,while maize yield per hectare and maize sowing area result in remarkable grain increment in the piedmont of Taihang mountain and in alluvial area of Haihe river.