This paper presents an ecological analysis of agricultural systems in arid region of Northwestern China. Emergy analysis, a method for environmental accounting developed by H.T. Odum in the Eighties, is appropriate fo...This paper presents an ecological analysis of agricultural systems in arid region of Northwestern China. Emergy analysis, a method for environmental accounting developed by H.T. Odum in the Eighties, is appropriate for this task because of its ability to transform different types of inputs to a common form （solar emergy） in order to allow scientific and objective comparisons across different period and regions. Taking Liangzhou and Minqin oases, located in the middle and lower reaches of the Shiyang River basin in Gansu province as a case study, the detailed structure of the agricultural process, input/output and emergy indicators of the systems are examined and compared for the years 1986 and 2000. Both the total emergy input and the total yield increased in the two oases. In Liangzhou Oasis the emergy of livestock production exceeded the traditional crop production, which still is the dominant production in Minqin Oasis. The emergy investment ratio, EIR, although increased in the investigated period, was less than 0.5 in both Liangzhou and Minqin oases, indicating that purchased materials and services were less than half the value of indigenous emergy sources exploited. As a consequence, the emergy yield ratio, EYR, was very high in both Liangzhou and Minqin oases. However, the increasing environmental loading ratio, ELR, and the decreasing environmental sustainability index, ESI, in the two oases illustrate a weakening sustainability of the two agro-ecosystems, and this tendency was more evident in the downstream Minqin Oasis, calling for more attention to the environmental degradation in the region.展开更多
Understanding the synergic relationship between the Grain for Green Program(GGP)and the agricultural eco-economic system is important for designing an optimized agricultural eco-economic system and developing a highly...Understanding the synergic relationship between the Grain for Green Program(GGP)and the agricultural eco-economic system is important for designing an optimized agricultural eco-economic system and developing a highly efficient structure of an agricultural industry chain and a resource chain.This study used Ansai County time series data from 1995 to 2014,applied vector autoregressive(VAR)models and used tools such as Granger causality,impulse response analysis and variance decomposition,to explore the synergy between the GGP and the agricultural eco-economic system.The results revealed a synergic and reciprocal relationship between the GGP and the agroeconomic system.The contribution of the GGP to the agroecosystem reached 34%,which was significantly higher than either its largest contribution to the agroeconomic system(20.8%)or its peak contribution to the agrosocial system(26.7%).The agroeconomic system had the most prominent influence on the GGP,with a year-round stable contribution of up to 55.3%.These results were consistent with reality.However,the impact of the GGP on the agricultural eco-economic system was weaker than the effect of the agricultural eco-economic system on the GGP.The lag of variable stationarity after the shock was relatively short,indicating that optimal coupling had not formed between the GGP and the agricultural eco-economic system.On the basis of enhancing the ecological functions,we should construct the agricultural industry-resource chain such that it focuses on promoting the effective utilization of resources in the region.In addition,the development of a carbon sink industry can be used to manifest the ecological values of ecological functions.展开更多
基金co-supported by National Natural Science Foundation of China(Grant No.40971272and No.40830746)
文摘This paper presents an ecological analysis of agricultural systems in arid region of Northwestern China. Emergy analysis, a method for environmental accounting developed by H.T. Odum in the Eighties, is appropriate for this task because of its ability to transform different types of inputs to a common form （solar emergy） in order to allow scientific and objective comparisons across different period and regions. Taking Liangzhou and Minqin oases, located in the middle and lower reaches of the Shiyang River basin in Gansu province as a case study, the detailed structure of the agricultural process, input/output and emergy indicators of the systems are examined and compared for the years 1986 and 2000. Both the total emergy input and the total yield increased in the two oases. In Liangzhou Oasis the emergy of livestock production exceeded the traditional crop production, which still is the dominant production in Minqin Oasis. The emergy investment ratio, EIR, although increased in the investigated period, was less than 0.5 in both Liangzhou and Minqin oases, indicating that purchased materials and services were less than half the value of indigenous emergy sources exploited. As a consequence, the emergy yield ratio, EYR, was very high in both Liangzhou and Minqin oases. However, the increasing environmental loading ratio, ELR, and the decreasing environmental sustainability index, ESI, in the two oases illustrate a weakening sustainability of the two agro-ecosystems, and this tendency was more evident in the downstream Minqin Oasis, calling for more attention to the environmental degradation in the region.
基金The National Key Research and Development Program(2016YFC0501707)The National Key Research and Development Program(2016YFC0503702)The National Natural Science Foundation of China(41571515)。
文摘Understanding the synergic relationship between the Grain for Green Program(GGP)and the agricultural eco-economic system is important for designing an optimized agricultural eco-economic system and developing a highly efficient structure of an agricultural industry chain and a resource chain.This study used Ansai County time series data from 1995 to 2014,applied vector autoregressive(VAR)models and used tools such as Granger causality,impulse response analysis and variance decomposition,to explore the synergy between the GGP and the agricultural eco-economic system.The results revealed a synergic and reciprocal relationship between the GGP and the agroeconomic system.The contribution of the GGP to the agroecosystem reached 34%,which was significantly higher than either its largest contribution to the agroeconomic system(20.8%)or its peak contribution to the agrosocial system(26.7%).The agroeconomic system had the most prominent influence on the GGP,with a year-round stable contribution of up to 55.3%.These results were consistent with reality.However,the impact of the GGP on the agricultural eco-economic system was weaker than the effect of the agricultural eco-economic system on the GGP.The lag of variable stationarity after the shock was relatively short,indicating that optimal coupling had not formed between the GGP and the agricultural eco-economic system.On the basis of enhancing the ecological functions,we should construct the agricultural industry-resource chain such that it focuses on promoting the effective utilization of resources in the region.In addition,the development of a carbon sink industry can be used to manifest the ecological values of ecological functions.
