相图法在区域农业经济系统能值研究中的运用

能值分析方法将不同的资源类型以统一的太阳能值来衡量,考虑了资源在生产过程中贡献力的差异,是研究和分析复杂能量系统资源代谢过程,评价过程的环境压力和发展可持续性的有效方法.运用能值方法对比分析了我国辽宁省两个经济与环境基础不同的农业生产系统,在发展过程中资源利用结构的变化,以及变化对当地环境和系统发展的影响,并运用相图分析方法更系统而全面地分析了系统的发展进程,现状和将来可能的发展方向.分析结果表明,同样的经济发展模式对自然环境条件相对脆弱的系统来说,所造成的环境压力和对系统可持续性的削弱程度更大.能值的相图分析法为能值方法的应用提供了一个有力的研究工具.

Ternary diagram used in emergy accounting of regional agricultural economic systems

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.