Evaluation Of Emergy And Life Cycle On Agro-systems Of Different Recycling Agricultural Models In Central Plains Economic Region

Today,agricultural industry in Central Plains Economic Region is faced with some problems of such as uneven distribution of natural resources,serious pollution and the unsustainable development of environment et al.In order to solve those problems,evaluations of agro-ecosystems of wheat-maize cropping system in four different agricultural models were proceeded,including straw returning to the fields to substitute 10% nitrogen(NT),cow dung returning to the fields to substitute 15% nitrogen(NM),mushroom residue returning to the fields to substitute 15% nitrogen(NJ),and no organic materials with traditional dosage nitrogen as the control group(CK).To assess their utilization efficiencies,the emergy and life cycle methods were used in the agro-ecosystems of four agricultural models.The main conclusions were as follows:1.Through emergy assessment,the emergy input structures of agro-ecosystems in three recycling agricultural systems were all improved.Specifically,in the three recycling models,non-renewable resource input was 4.42%-6.00% lower than that in the traditional agriculture model,the total emergy output was0.50%-6.35% higher than that in the traditional one.The emergy assessment indexes of recycling agricultural system were better than that in the traditional model,with the renewable ratio being642.72%-730.06% higher than that in traditional agriculture model,the environmental loading rate being86.51%-88.87% less than that in traditional agriculture model,the net emergy yield ratio being0.91%-9.17% higher than that in traditional agriculture model,and the sustainability index being704.68%-848.25% higher than that in traditional agriculture model.On the whole,in comparison with the traditional agriculture model,there were better emergy input structure,higher emergy output and better sustainability of each agro-ecosystem in the three recycling agricultural models.Furthermore,NM and NJ patterns were better than the other two models on emergy assessment.2.The life cycle assessment showed that the total environmental impacts of wheat-maize cropping system were reduced in the agro-ecosystems of three recycling agricultural models.Compared with the traditional agricultural model,the global warming effects of three recycling agricultural models were reduced 50.88%-51.45%,the environmental acidification effects of them were decreased 10.98%-14.04%,eutrophication effects of them were cut down 0.04%-1.93%,and the toxic effects of them on environment and human were declined 2.9%-13.62%.On the whole,the environmental impacts of three recycling agricultural systems were less than that in traditional agriculture model.Furthermore,NM and NT models were superior to the other two models based on life cycle assessment.So fertilizer and pest management methods should be optimized to reduce the negative impact of environment to agricultural production.3.Emergy-life cycle assessment indicated that the comprehensive benefits of three recycling agricultural systems had an advantage over the traditional agriculture model.In detail,compared with the traditional agriculture model,the resource reduction index was increased 1.45%-53.36%,the recycling utilization index was increased 38.67%-45.94%,the economic competitiveness index was raised11.11%-730.06%,the pollution reduction index was gone up 2.53%-51.15%,and the sustainable development index was increased 642.72%-848.25%.Overall,the three recycling agricultural systems embodied the principle of "reduction,recycling,reutilize and controllable",also achieved the purpose of energy-saving and emission reduction.Additionally,NM model was better than the other three models through Emergy-life cycle assessment.In conclusion,it was effective to evaluate the field systems of different agricultural patterns that with emergy and life cycle assessment methods.The results demonstrated that recycling agricultural systems were better than traditional agriculture system.It was displayed in some aspects: firstly,in three recycling agricultural systems,emergy input structures and emergy indexes were better than those of traditional agriculture system;secondly,emergy output was higher than that of traditional agricultural system;thirdly,their environmental impact was inferior to traditional agricultural system;at last,their resource reduction index,recycling utilization index,economic competitiveness index,pollution reduction index and sustainable development index were better than those of traditional agriculture system.Consequently,recycling agricultural models are more suitable for agricultural development in Central Plains Economic Region,and can be adapted to local conditions for development.