| Agricultural ecosystem has both natural attributes and social attributes; the research method of traditional comparative advantage theory mainly evaluates the comparative advantages by using currency or energy from the angle of economics. However, the pure currency evaluation method causes more and more criticism, while the energy analysis has defects which are difficult to overcome. In consideration of the actual agricultural ecosystem in Huaihua, the author holds that it is necessary to conduct energy analysis on agricultural ecosystem.For energy analysis method, its main difference with the traditional single method of economics and energetics lies in its quantification expression of the natural resources and biosphere process contribution; it adds free environment-s ource elements to the analytic system and takes into consideration the influence on the environment caused by system process in a more complete way. This comprehensive consideration is not only reflected in the calculation of energy t ransformation rate of main resources and biosphere process, but also in the ana lysis process of the specific energy system.In terms of theory, energy analysis provides a common standard and comprehensive analysis method for measuring and comparing various ecological flows and develops a new approach of quantitative analysis research for ecological-economic system, which helps coordinate ecological environment and economic development.This study has performed the general researches into the following:Developing the energy analysis table of agricultural ecosystem of Huaihua, and establishing the index system of energy analysis for agricultural ecosystem of Huaihua (such as net energy output rate, energy investment rate, environment load rate, etc.). It identifies the development trend of the agricultural ecosystem of Huaihua through making a proper judgment on the evolution trend of the system, and also conducts a quantitative analysis evaluation on the sustainability of agricultural ecosystem in this region.For the analysis of energy evolution of agricultural ecosystem, the years between 1980 and 2008 are chosen as the time series, and a further study on the energy trend of the agricultural ecosystem and its succession track in Huaihua for 27 years has been conducted to explore the law of the agricultural ecosystem structure and changes of function in Huaihua and to predict the future development trend of the system.This paper mainly focuses on the following areas:This paper regards agriculture as a combination of natural ecosystem and socio-economic system. By adopting internationally advanced energy theory and methods to carry out scientific evaluation to the whole system and by making comprehensive analysis on the contribution of natural ecosystem made to agriculture and the contribution of socio-economics made to agriculture, we have made a step forward in the analysis and understanding of agricultural ecosystem.A comparative advantage model is built based on energy analysis and the agricultural ecosystem in the typical counties in Huaihua with different agricultural ecosystems is analyzed as case study. The analysis result shows that the newly developed energy comparative advantage index can measure the evaluated agriculture in a more complete and scientific way and provides a guidance for the scientific and reasonable development of the agricultural ecosystem.The objects of the study are more specific and profound. Most objects of the study belong to the macro-agricultural ecosystem and the research into single specific crop system fills in the gap of energy study. Now the study of comparative advantages is conducted on a national or provincial basis, and there are very few cases of study based on county dimension. The drawback of the macro-agriculture study is that the differences between different crops and regions are easily ignored, thus causing the one-sidedness in understanding. This study investigates all different crops in different counties and is an in-depth representation of energy study.The final conclusions are as follows:The net energy output rate in rice system in the typical counties:Yuanling, Zhongfang, Huitong in Huaihua City ranks in the following way::Zhongfang (34.11%)> Yuanling (29.74%)> Huitong (23.98%)> Huaihua (15.27%). Zhongfang ranks the first, and the reason is that, in the process of rice production, the investment in buying energy is low, while the free energy of natural resources is high. When the net energy output rate of rice system is less than one, it shows that the input and output is not reasonable and the economic benefits are not favorable.The net energy input rate in rice system in the typical counties:Yuanling, Zhongfang and Huitong in different agricultural ecological areas in Huaihua ranks in the following way:Huaihua (11.41)> Yuanling (8.35)> Zhongfang (5.75)> Huitong (3.40).Huitong enjoys the lowest energy investment rate while Huaihua enjoys the highest. It shows that less purchased energy is utilized in the usage of free environment resources of per unit of rice in Huitong; so the rice system is low in production costs, exerts less pressure on the environment and hence is more competitive in the market.The energy output rate for corn ranks in the following way:Zhongfang (239.48%) > Huitong (228.39%)> Yuanling (218.59%)> Huaihua (172.66%). The energy output rates of Zhongfang and Huitong are high, while that of Huaihua is low, indicating that more energy is purchased in the production of corn crop in Huaihua, so its production cost is high and is weak in competition in the market.The agricultural production system of Huaihua City is high in energy inve stment and in pressure on the environment, so a large-scale modern agricultural construction can be carried out; by using modernized agricultural methods and advanced agricultural business ideas and supported by the advantages of natur al environment, the functional efficiency of the system operation structure can be optimized and hence the energy output rate can be improved.From the analysis on the energy input proportion in Huaihua City, we can see that the input of industrial supporting energy is higher than the input of organic energy; so the increase in input of organic energy will improve the ec onomic benefits of agriculture.From the evolution of agricultural ecosystem in Huaihua City, we can see that the agricultural ecological economic benefits improves continuously. This is thanks to the increase in the investment of industrial supporting energy by Huaihua City, so the investment structure of the system energy is more reasonable. This means that Huaihua City is breaking away from backward production methods and is advancing towards a modernized agriculture.
|
PDF Full Text Request