Modeling Farm Household''''s Grain Production Function in Economically Developed Coastal Areas of Southeast China:A Case Study in Changshu City of Jiangsu Province, China
东南沿海经济发达区域农户粮食生产函数研究——以江苏省常熟市为例

Because the economically developed coastal areas of southeast China possess quality arable land that can be cultivated twice annually,how to increase the grain yield per unit(GYPU) in this region is particularly important for China.This study attempts to analyze the factors influencing GYPU so as to bring forward policy suggestions for steady increase of GYPU.Changshu city was selected as study area and the data were collected through household survey and Statistic Bureau of Changshu City.Based on the data of household survey,Cobb-Douglas production function which was widely utilized to study the relationship between output and input was constructed in this paper.The GYPU(considering cropping index) was selected as dependent variable and 6 factors that maybe influence GYPU were selected as independent variables i.e.the total grain crop area(the product of arable land size and cropping index),labor force used in unit area,quantity of chemical fertilizer (nitrogen fertilizer,phosphorus fertilizer and potassium fertilizer) applied in unit area,capital inputs(the sum of capital inputs of seed,irrigation and mechanic equipments) in unit area,the quantity ratio of part-time labors to total labors and the rates of crop residuals retuning to soil.The method of partial correlation analysis,which can study the linear correlation relationship between two variables was utilized to assess the influence of land size and cropping index,mechanic inputs,seed inputs,and irrigation inputs on GYPU.The conclusions were as follows: 1) both arable land size and cropping index had significantly positive effects(partial correlation coefficients(PCC) are 0.331 and 0.430 respectively;probability under null hypotheses(P) are 0.002 and 0.000 respectively) on GYPU;2) neither the labor inputs on farming nor the labors' behavior of hunting part time jobs had significant effects(elasticity of output(EO) are 0.045 and-0.011 respectively;P are 0.769 and 0.801 respectively) on GYPU;3) nitrogen fertilizer,phosphorus fertilizer,and potassium fertilizer had negatively,no,and positively significant effects(EO are-0.070,-0.039 and 0.127;P are 0.007,0.361 and 0.001 respectively) on GYPU respectively;4) total capital inputs had significantly positive effects(EO=0.573,P=0.000) on GYPU,among which the mechanical and capital inputs contributed most(PCC=0.242,P=0.026);5) rates of crop residuals returning to soil had significantly positive effects(EO=0.002,P=0.000) on GYPU.For steady increase of GYPU,policy suggestions are as follows: 1) stabilizing and strengthening the policy of arable land management in a moderate size;2) increasing the subsidy for wheat production;3) popularizing recommended fertilization based on soil testing;4) developing and popularizing machines of rice cultivation and harvest;5) encouraging farmers to use electricity as an substitute fuel of rice straw.