Abstract:Emergy analysis was used in this paper to analyze two agricultural systems in Liaoning Province of Northeast China and compare resource use, productivity, environmental stress and sustainability for 25 years. Structure and development of indigenous economy were considered in analyzing the development of agricultural production. Chaoyang is an important base for agricultural production in Liaoning Province while Fushun is a main industrial base of Northeast China. The results of the analysis demonstrated a growing reliance on purchased resources in two agricultural systems. The fraction of purchased inputs had grown by 1.88 times and 1.08 times from 1980 to 2005 in Chaoyang and Fushun agricultural systems, respectively. Because of higher dependence on purchased non-renewable resources, production process placed greater load on the environment. Ecological sustainability of studied systems decreased dramatically during the 25 years. In this process, Chaoyang agricultural production underwent a more rapid decrease in sustainability as sustainability index (SI) decreased from 1.25 to 0.11. The similar process of industrialization brought more stress to the vulnerable environment of Chaoyang. While the use of higher quality inputs resulted in the greater yields per area from two agricultural systems, the efficiency of these investments did not increase correspondingly. Environmental protection and restoration rather than greater amount of purchased non-renewable resources should be a good strategy to reduce the loss of non-renewable indigenous resources in the two systems. Ternary diagrams were used as a tool to compare and evaluate the improvement of the two agricultural systems, and then the interaction between systems and the environment was recognized and evaluated. The graphic analysis is a versatile and adaptable tool for presenting different systems and the same system at different periods of time.