Emergy evaluation on production pattern of raising geese in corn field

Abstract

Corn is one of the main commercial crops in China,and the increase of its quality and productivity is the key to resolve the current problems of food shortage,resource bottleneck and food security.Raising geese in corn field(hereinafter referred to as RGICF)is a compound production pattern based on the principle of"agropastoral integration",which was proposed in 2011,and whose core content is compound production model which use the resources such as weeds,bottom leaves of crops,etc.in tillage system to raise poultry.However,there are still some unknown questions to be answered in a systematic way,such as the system productivity,environmental load and sustainability of the system,etc,and these questions must be answered before the popularization of"agro-pastoral integration"technology.Emergy analysis capable of accounting for both economic aspect and the natural contribution to production on a common basis,allowing meaningful comparison across different systems,has been applied in many cases and has been proved to be a powerful tool to assess ecological economic systems and processes,with special focus on the agricultural field.With the purpose of gaining a thorough understanding of the productivity,environmental load and sustainability of RGICF,this study applied the approach of emergy analysis to compare the RGICF treatment with the traditional pattern of corn planting(CK).According to the new development of emergy methodology,the renewability factor of each item was incorporated.Emergy indices such as emergy investment ratio(EIR),emergy yield ratio(EYR),emergy self-supporting ratio(ESR),environmental loading ratio(ELR)and environmental sustainability index(ESI),feedback ratio of yield emergy(FYE),emergy index of product safety(EIPS)and the ratio of output to input were applied to characterize the resource use,production efficiency,environmental impact,the overall sustainability and the economic benefit of the studied systems.The result showed that the EIR and FYE in RGICF were 1.65 and 3.85 times respectively as much as those of CK treatment.In the aspect of environmental load and sustainability,the ELR of RGICF treatment was 2.90 lower than that of CK treatment;and the ESI of RGICF treatment was 20.56 higher than that of CK treatment.In the aspect of product safety,the EIPS of RGICF treatment was 0.41 higher than that of CK treatment.In the aspect of the productivity,the EYR of RGICF treatment was 0.34 lower than that of CK treatment,and the ESR of RGICF treatment was 0.06 lower than that of CK treatment.In the aspect of the economic benefit,because of the high economic input,the ratio of output to input of RGICF treatment was 0.39 lower than that of CK treatment,but the net income of RGICF was 2.02 times as much as that of CK treatment.In conclusion,the pattern of raising geese in corn field is promising in the terms of environmental load,economic benefits and system sustainability,but further improvement is still needed in production efficiency and self-sufficiency.