Quantitative Assessment of the Impact of China's Direct Grain Subsidies on Grain Yield--Based on the Empirical Analysis of Panel Data Pertaining to 29 Provinces in the Period 2004-2007

We build the influence function empirical model of China's grain production at the present stage in view of the factors influencing direct grain subsidies,using Cobb-Douglas production function model.And we estimate the elasticity coefficient of impact of China's direct grain subsidies on grain yield,using the panel data pertaining to 29 provinces in the period 2004-2007;comparatively analyze the validity and limitation of policy factors of direct grain subsidies on China's grain yield.The results show that at the present stage,the elasticity coefficient of impact of China's direct grain subsidies on grain yield is 0.002 3,and under the existing subsidy system and level,direct grain subsidies play a positive role in increasing grain yield,but the role is limited;the elasticity coefficient of impact of the food price on grain yield is much larger than that of impact of direct grain subsidies on grain yield.Therefore,the government should strengthen and improve direct grain subsidy policies;in the mean time,pay full attention to the use of market mechanism to consolidate the basic role of the food price in promoting food security to a great extent.