Study On The Comprehensive Productivity Accounting Of Cultivated Land

The final goal of carrying out the strict management regulation of land rescources is the national food security. It is not only the quantity stability but also the quality of cultivated land for the land security the final purpose of which is comprehensive productivity stability. For China, which is on the industrialization and urbanization accelerating development stage, land supply and demand contradiction has been the protuberant problem, and the decreasing trend of land resources haven not been reversed in a short time. Those areas, major grain intensive production areas of eastern plains, and the coastal and suburb developed areas, have formed the passive situation of high input, low efficiency and heavy pollution. Agricultural has deteriorated significantly because of overuse of chemical fertilization and water resources, soil degradation and pollution. The conditions of unstable quantity and quality of cultivated land make it necessary to carrying out accounting comprehensive productivity. The development direction must to be the green comprehensive productivity, gradually integrate environmental issues into the production concept and investigation and evaluation system.Through cultivated land comprehensive productivity accounting, which can reflect the quantity and quality of situation, in essence realized fundamental requirements of equal attention to quantity and quality of cultivated protection. On the basis of comprehensive productivity accounting results, it can coordinate the relationship between food security and industrialization, urbanization and ecological balance, and ultimately realize of socio-economic sustainable development.According to the different resources and environment conditions, using the fuzzy clustering method the zones for ecological type are classified. On the basis of agricultural land classification and gradation results, through investigating supplementary sampling points, the indexes of natural quality and land use were used to construct theoretical and realistic linear regression models for yield per unit, respectively, and practical productivity was obtained from statistical data.In view of resources environmental issues existing in resent use of the cultivated land, use the environmental economic method to estimate the resource consumption and environment degradation loss. The main results as follows:(1)On the basis of agricultural land classification and gradation, it is to construct of cultivated land comprehensive productivity accounting model, and define the concept and meaning. The comprehensive productivity can be divided into three levels: theoretical productivity, realizable productivity and practical productivity. The development direction must to be the green comprehensive productivity, gradually integrate environmental issues into the production concept and investigation and evaluation system.(2)The spatial distribution of land comprehensive productivity has remarkable change. The productivity of per unit area from southeast to northwest shows the trend of gradually decreasing. The method of accounting comprehensive productivity based on agricultural land classification and gradation is of scientificity,rationality,feasibility, and that is the important approaches and methods to deepen the management of balance between quantity and quality of cultivated land resource.(3) Reference to the environmental economic method to estimate the resource consumption and environment degradation loss. The resources aspects: it has lost 3.67×10~9kg yield because of the he cultivated land consumption from 1983 to 2003, 8.65×108 Y/a because of groundwater consumption and 4.81×10~9 Y/a because of soil and water loss. The environment degradation aspects: the air, soil and nitrate pollution respectively cause losses of 1.20×10~7 kg /a, 1.20×10~7kg and 8.01×10~7Y/a. Through the green accounting, it showed that with protection of cultivated land resources it must pay more attentions to the quality of cultivated land.