Emergy Analysis And Model Building Of Agro-ecosystem In Ningxiang County

On the basis of the review of the agro-ecosystem researches, this dissertation applied the emergy analysis theory and input-output theory to analyse the input and output situation of the agro-ecosystem in Ningxiang County from2003to2010, to study the intrinsic relationships within the system inner elements consisted of the system and that one between them and the extral environment of the system, and revealed the factors and characteristics influencing the system succession. Then the agricultural ecological model of Ningxiang County was built up, as a result, to prevent soil degradation was associated with a decrease in soil fertility, enhance the land use, soil erosion and management of prevention and cure of diseases and pests.the foundation of the reasonable use of agricultural resources and the county’s agro-ecosystem sustainable benign circulation was established. For the following main results and conclusions.(1) Choose9indicators for a comprehensive analysis, such as Emergy Yield Ratio, Emergy Invetment Ratio,Environmental Load Ratio, Environmental Sustainability Index and so on. Based on our study, the value of ESR is0.14in2010.EYR4.36.EIR5.03,ELR2.61,ESI1.67, SSD0.46.(2) The renewable industrial assistant emergy of Ningxiang County is very low, but the industrial assistant emergy support to the largest proportion of the total input emergy. It means the operation and development of agricultural system mostly depends on the emergy from social-economic system.(3) Human input account for more than60%of the renewable energy. It shows that the agricultural mode of Ningxiang is labor-intensive industry. The output of Ningxiang agricultural ecosystem shows a trend of rising, which mainly includes the animal husbandry and planting industry, accounted for about99%. The development of fisheries and forestry is relatively weak, and agricultural production structure is unitary.(4) EYR was relatively high. which illustrated that the production efficiency of agricultural ecosystem is very high, and the overall function is properly good. The environment load rate is below the national average of5.89, so the agricultural ecological system didn’t achieve optimal allocation of space resource utilization, and there was a large room for improvement. (5)The agro-ecosystem has low production dominance and high stability indexes. It showed that the coordination of Ningxiang agricultural system structure is not high, but the stability is better.In conclusion, based on the field survey, combined with the related index analysis, the agricultural production mode of Ningxiang is proposed:pigs, bogs, food (fruit, tea) mode; Fruit (food) composite food crops planting mode; Rice/fish and ducks intercropping mode; The courtyard compound ecological agriculture pattern; Agricultural industrialization development mode, etc.