| Pi river ecological economic zone is created to eliminate poverty,develop modern agriculture,process agricultural and sideline products and implement new agricultural management system.It focus on the sustainable development and engage in fighting against pollution of pi river,and it will benefit the regional economic development as well as promote the elimination of poverty of this area.Shou county has a large agricultural yields of Pi rival drainage area,the agriculture is the pillar industry of this county.Hence,whether the agriculture development could keep high efficiency and be sustainable or not,it will directly impact the economic and social development.In this paper,we take Shou county as an example,using the emergy theory to analysis the input and output of three different management models of national farm,large crop-land owners and traditional farm and three different cropping patterns of wheat-rice,wheat-soybean and mat grass-rice in the Pi river ecological economic zone.We quantify and analyze the emergy structure of input and output of different agro-ecosystem.We also create a agro-ecosystem emergy analysis index system,which include industrial assistant emergy ratio,organic assistant to value ratio,environment load ratio,emergy input intensity,emergy investment ratio,value output density,emergy investment ratio,the net energy output rate and sustainable development index value.At the same time,we not only compare the wheat-rice agro-ecosystem under different management models of national farm,large crop-land owners and traditional farm,but also the wheat-rice and wheat-soybean cropping patterns of national farm and wheat-rice and mat grass-rice cropping patterns of traditional farm.We analyze and evaluate the resources use and ecological economic benefits of agro-ecosystem under different management models and cropping patterns.We concluded that:1)due to the high level of mechanization,the productivity,economic benefits and the resource utilization rate were higher under the scale production such as national farm and large crop-land owners,however,the unitary and traditional energy inputs such as fertilizers,pesticides and machinery were too heavy and the organic manure was insufficient,resulted in a large environmental load and a low environmental sustainability.In comparison,the traditional management of farmer has a high ecological benefit and management level but lowe economic benefit,productivity and resource utilization rate.2)The grain crops were dominant in this region,the plant structure was unitary.The wheat-rice crop rotation has a high modernization degree,economic standard and resource utilization rate.However the nonrenewable inputs such as fertilizers,pesticides and machinery were higher,resulted in a higher production costs.In comparison,the wheat-soybean rotation has less environmental stress and was sustainable,the mat grass-rice rotation has lower mechanization level and productivity,the input of fertilizers,pesticides and work force were larger,hence need more managements and hard to plant in a large scale.3)In this region,all the agro-ecosystems have low renewable resources utilization rate,the agricultural production largely relay on the input of nonrenewable industrial resources.The sustainable index is below 1 for all and the sustainability was low for agro-ecosystems.Our study suggested that during the development of modern agriculture in Pi river ecological economic zone,we should pay attention to improve the energy input structure,meantime we should promote scale management and protect the environment of agro-ecosystem.We also need to adjust the planting structure and strengthen the development of agricultural industrialization,thus realize the sustainable development of agro-ecosystem in Pi river ecological economic zone.Currently,this region is planning to create modern agriculture industrial center and build a whole region agricultural and sideline products processing system.The infrastructure also need to be strengthened in order to enhance the modern agriculture.On schedule,by 2020 the region’s total grain yield would reach 32.5 million tons,the mechanization rate would up to 95%,the renewable resources utilization rate is predicted to 74% and the sustainable index of agro-ecosystem is expected up to be 0.56,thus,the sustainability of agricultural eco-economic system would be significantly improved. |
