Study On Cultivated Land Comprehensive Productivity Evaluation Based On Applicatiao Of Famland Classification

Cultivated Land is the most important natural resource and means of production without which human cannot live. To guarantee the safety of Cultivated Land, on the one hand, the quantity of Cultivated Land should keep stable. More importantly, the quality of Cultivated Land should keep stable. The ultimate objective is to keep the productivity of Cultivated Land stable. It needs correctly and objectively evaluating the productivity of Cultivated Land, mastering its size, distribution and potentiality, advances corresponding measures accordance with the existing problems. So that it is helpful to utilize and protect cultivated land reasonably, coordinating relationship among food security, industrialization development and urbanization development, and ecological balance, promoting sustainable utilization of Cultivated Land, realizing sustainable development of the whole society.Based on the correlation between, this paper defines the concept of comprehensive productivity of Cultivated Land. Then it analyzes its connotation and composition systematically. This paper put forward that comprehensive productivity of Cultivated Land is composed of three levels including natural productivity, utilizable productivity and actual productivity. Based on analyzing the relationship between farmland classification and comprehensive productivity of Cultivated Land, this paper put forward evaluation way of comprehensive productivity of Cultivated Land based on farmland classification according to applicability and limitation.Take Fufeng County, Shaanxi province for example, it take the farmland classification as evaluation unit. Firstly it uses the attenuation method according to formation mechanism of productivity of Cultivated Land. Based on potential productivity of Cultivated Land's light and temperature determined by farmland classification, it takes the nine indexes which including plough layer, soil texture, soil structure, soil organic matter content, soil total nitrogen, soil available phosphorus, soil available potassium, soil pH and terrain slope as the correction factor, calculate soil modification coefficient using PI model to determine the natural productivity of Cultivated Land per unit area. Then through area-weighted, it can calculate that Fufeng County's natural productivity of Cultivated Land in 2005 is 987 thousand tons. On this basis, it selects six human input factors including seeds input, fertilizer input, pesticide input, mechanized farming input, irrigation input and labor force input. Then using Cobb-Douglass production function model, it can calculate that Fufeng County's utilizable productivity of Cultivated Land is 518 thousand tons. According investigation data of Fufeng County's rural society and economy, it can calculate that Fufeng County's actual productivity of Cultivated Land is 394 thousand tons.Based on actual productivity, using the utilizable productivity and natural productivity as expectation, it can respectively calculate that realistic potential and utilizable potential of Fufeng County's cultivated land's productivity are 593 thousand tons and 124 thousand tons. According the distribution law of cultivated land's productivity potential, it put forward several measures and suggestions which can protect and promote Fufeng County's comprehensive productivity of cultivated land.