Assessing theory of agroecosystem at county scale and its case study

On the basis of internal and external ecological agriculture assessing,the paper constructs the theory of regional agroecosystem assessment that consists of assessing index system,appraising mathematic model and appraising principle.At the same time,Deqing county is singled out for a case study of agroecosystem at county scale.From 1995-2003,Deqing county agroecosystem of county presented ascending trend on summing index because of the higher efficient resource using.The ecological index was close to the summing index in later period,but economic index and social index produced negative function.Furthermore,there was dominant position of nature environment in developing agroecosystem at Deqing county.For improving the level of developing agroecosystem at county scale,it should enhance the economic development of agroecosystem.