Study On Evaluation System Of Regional Cultivated Lands Productivity Stability

Grain production is the basis of social stability and development, therefore, solve the food problem will become a basic objective for social and economic development. However, with increasing of population and resource exhaustion, the confliction between human demands for food strengthen and cultivated land reducing is gradually intensified. Productivity is the basic characteristic of farmland. The stability of productivity implies the structure, function and developmental directions, which has become a hot issue to solve the current food security. Therefore, how to ensure the continuous stability of farmland productivity were the key to ease confliction between people and land use. Nevertheless, there are no integrated theories, means and methods on the stability of farmland productivity at present. Based on previous research, the paper focus on Hebei province case and discuses the theory and methods on assess stability of farmland productivity in view of trends and fluctuations. The main findings as follows:1. Stability theory and methodology of farmland productivityBased on the ecosystem function of farmland and characteristics of food productivity, the paper pointed out connotation of food productivity stability includes long-term sustained and stable growth of output in food production and minimize fluctuations. By Empirical mode decomposition (HMD) method, the food productivity was divided into trends and fluctuations. And then, stability models fit the two factors effectively to build evaluation system of productive stability.2. Stability evaluation of farmland productivity in Hebei province(1) From 1978 to 2005, the stability of grain output in Hebei Province was fluctuating from increase to decrease. There are two significant stages. The stability of crop productivity was worst from 2003 to 2005, recession in a stage of productivity. As to stability index from 1978 to 2001, there were 16 years in the unstable grade, 4 years in the stable grade and 4 years in the most stable grade.(2) During the formation of crop productivity stability in Hebei Province, wheat and corn output plays the most important role on total production. Piedmont of the Taihang Mountains and northern Hebei province has the significant impact on overall stability. (3) In Hebei province, stability of crop productivity in twenty seven counties is worst and the corresponding stability index is negative; stability of the crop productivity in one seventeen counties belongs to the unstable grade; sixty four counties have poor food productivity, belonging to the stable grade; stability of crop productivity in thirty five counties is best. The cultivated land areas which belong to the unstable grade accounted for 48% of the whole province.3. Factors of productive stability in Hebei Province(1) From 1978 to 2005, grain output increases 1.72% in Hebei province. There are several factors could influence stability of crop productivity and the contribution rate is various. The cultivated area increasing has a positive effect on the crop output and accounts for 51.99%; effective irrigation area accounts for 38.68%; scientific and technological progress accounts for 12.73%. However, Agricultural input and business spending suppress the output increasing.(2) The factors which influence output fluctuation in Hebei province were classified into hazard area,effective irrigation, planting area, supporting spending, rainfall and fertilizer application according to contribution rate to crop productivity fluctuation. They could account for 78.82% compare with other factors. Analysis by influence degree, we conclude that fluctuation of natural resources,permanent assets and various constituents was the main contributor for crop productivity fluctuation in Hebei province.