Study On Production Capacity And Population Supporting Capacity Of Cultivated Land Dynamic Variation In Deyang

The arable land is the most precious part of land, the main origin of human's food, and the most essential factor of sustainable socioeconomic development. However, in recent years, along with the unceasing intensify of population-land contradiction and the problem of grain security, it becomes an urgent and arduous work to balance the population, food-stuff and the arable land now. As an important evaluation index on revealing and measuring the complex relationship and space-time difference among population, food-stuff and arable land, actual productivity and population supporting capacity of arable land have objectivity and stability strongly, although being the variables. The meaning of research on this is providing the scientific gist and practical instruction for the government constituting land use plan, population policy, the ecological environmental policy and so on.Deyang of Sichuan province is chosen to be the study region. Taking Jingyang, Mianzhu and Zhongjing as representative counties of plain, mountainous area and hill to launch the research concretely. As for representative counties of plain, mountainous area and hill, we studied Jingyang, Mianzhu and Zhongjiang separatively. By statistical yearbooks during 1996-2006 and field survey, dynamic variational rules of arable land and population, actual productivity and population supporting capacity of arable land during 1996-2006 quantitatively were analyzed through typical-zetetic-analytic method. The method of multiple regression statistics also was applied in analyzing influencing factors of population supporting capacity of arable land thoroughly, and the suitable countermeasure and suggestions were proposed on improving population supporting capacity and actualizing sustainable development of resources for various regions in the study.The study indicated that:(1)From 1996 to 2006, the arable area of three counties all took on downtrend year-by-year and separately decreased by 11.03%, 12.16% and 7.40%, but the total population increased tardily by 10.74%, 0.51% and 3.44%. As to per capita arable area, Mianzhu>Zhongjing>Jingyang, and decreased by 19.67%, 12.83%, 10.47% from the top separately in Jingyang, Mianzhu and Zhongjiang during 1996-2006. Thus, there was increasingly prominent population-land contradiction in study region, and the situation couldn't be optimistic.(2)In study region, the total yield ability of arable land was the most in Zhongjing compared with other counties, about 30×10~4t. But by contraries, the order from high to low was Jingyang > Mianzhu > Zhongjiang on average productivity of arable land., however, the difference among them was not obvious. During 1996-2006, total yield ability of arable land in the three counties had decreased by 23.45%, 15.32% ,27,61%, and average productivity of arable land had also decreased by 21.94% in Zhongjiang. But the average productivity of arable land in Jingyang and Mianzhu fluctuated steeply, increasing by 6.52% and 2.56%.(3) Population supporting capacity in Deyang presented decreasing trend during 1996-2006, which was surplus before the year of 1999 and overloading after that, the situation was very austere. In the study region, population supporting capacity of arable land dad fluctuant decrease, it overloaded or met critical state in Jingyang and Zhongjiang county, but the situation in Mianzhu wasn't bad, being surplus.(4)The multiple regression linear equation in the study was rational. Correlation factors were the arable land, the production technical level of agricultural labor and grain yield, negative correlation factor was the population density and people's material life standard. Technical factor was most significant to population supporting capacity, and correlative analysis indicated that, the speed on technology advancement deeply effected the productivity level of arable land and its dynamic variation in study region, and prospering agriculture through science and technology was effectual approach and exigent demand to direct improve the productivity currently. The negative effect from population density and material life standard was not obvious, but can't be ignored.(5)Accordingly, suitable effectual countermeasure to improve population supporting capacity of arable land should be carried out by the government and related department in Deyang, considering influence extend of each factor with local fact. And instruction for sustainable development of population, grain and arable land should be also provided, in the presupposition of entironment balance conservation. At one time, the corresponding gist of dicision-making for implementing arable land's ptotective strategy and insuring grain security should be provided too.