The regional agricultural system (RAS) can be divided into three subsystems: ecological, economic, and social. Thisarticle examines the use of the harmony coefficient (HC), efficacy coefficient, rank of the harmony coefficient (RHC), andits appraising index system within the RAS. The harmony coefficient function was developed using a variance coefficientand then applied to Ziyang District, Yiyang City in Hunan Province (ZYH), China, as a test case. From 1995 to 2002, the HCof RAS increased from 0.2982 to 0.4826 and the RHC increased from 3 to 5, although the HC trend was an “n” type ingeneral. This suggests that the HC was weakly maladjusted and the RAS was not harmonious. The HC of the ecologicalsubsystem decreased from 0.3898 to 0.2850, and its RHC from 4 to 3, with the HC trend following the “n” type. For theeconomic subsystem, the HC value increased from 0.5767 to 0.7458 and the RHC from 6 to 8. However, the trend in HC forthe economic subsystem was of the “U” type. The HC of the social subsystem increased slightly from 0.4948 to 0.4663,and the RHC did not change in value. From the HC trends, the HC curve of the economic subsystem is above the HC curveof ZYH and the HC curve of the ecological subsystem is below the HC curve of ZHY. Hence, the ZHY environment hasbeen destroyed by economic development. Environment and social building should be regarded as important issues inthe future and promoting RAS harmony development should be considered. The results of the theoretical analysis matchfairly closely with reality, and suggest that the harmony theory is feasible in appraising RAS development phases.
