Theory and Application of Emergy Analysis in Arid Region in Northwest China

Through summarizing the research status of emergy analysis at home and abroad,the basic connotation and judgment standard of emergy and indices were introduced in detail. Considering the characteristics of emergy analysis applied to the specific geographic scope in arid region in Northwest China,the problems which should be paid attention to and the corresponding suggestions as well as counter measures were put forward. Finally,trends in the further study of emergy analysis were forecasted.

EMERGY ANALYSIS OF GRAIN PRODUCTION SYSTEM IN JIANGSU AND SHAANXI PROVINCES

Efficiency and sustainability of grain production are now important in China. In this study, the grain production systems of Jiangsu and Shaanxi Provinces were compared, to analyze their efficiency and sustainability in terms of utilization of natural resources, inputs of purchased energy and materials, and outputs. Flows of energy and materials between environment and human society were identified, and the natural and human work involved in generating inputs as materials or energy were valued in terms of equivalent amount of solar energy required for their production using emergy method. The results showed environmental resources were continually playing a less important role in the systems, when inorganic subsidiary emergy inputs increased drastically while organic ones decreased or increased little. Deterioration of input emergy structure affected the systems′ efficiency and sustainability,resulting in emergy investment ratios and environmental loading ratios increasing while yield ratios and sustainability indices decreasing. In general, efficiency and sustainability of grain production in Jiangsu are worse than those in Shaanxi. This analysis also suggested that inorganic subsidiary emergy should be introduced properly, and peasants in Jiangsu should utilize natural conditions wisely while those in Shaanxi pay enough attention to soil and surface water conservation.

Emergy analysis of paddy farming in Hunan Province, China： A new perspective on sustainable development of agriculture

The multi-functionality of paddy farming has become a hot issue recently. Paddy farming provides numerous ecosystem services that are crucial to human well-being. However, evaluation of the contribution of paddy farming to human well-being usually focus on its economic value, while its non-market services are usually ignored. Only evaluating the market profits or market relative benefits cannot reflect comprehensively the contribution of paddy farming to people＇s well-being. This will affect people＇s choices for or against paddy farming activities and people＇s opt for invest or not invest in it. A comprehensive evaluation of paddy farming can provide an important reference for the government and society to conserve the multi-functionality of paddy farming and achieve sustainable development. To this end, this paper reports a case evaluation of paddy farming in Hunan, the largest rice producing as well as rice yield province in China, and uses emergy theory to make a comprehensive evaluation for paddy farming. The emergy evaluation results of the paddy ecosystem in Hunan are as follows： in 2010, the input emergy of the paddy ecosystem in Hunan is 2.51E＋22 sej and the output emergy is 6.31E＋22sej. For the input emergy, the part from natural resources is 1.96E＋21 sej and the part from human society is 2.32E＋22sej; for the output emergy, the part from products is 2.22E＋22 sej, the part from impositive externality is 4.16E＋22 sej and the part from negative externality is –7.41E＋20 sej. Taking the non-market outputs into consideration, the gains from the human economic society＇s 1 $ input in paddy farming, emergy sustainability index（ESI） and emergy profit rate are respectively 2.73 $, 3.53 and 151.31%. If the evaluation leave out the non-market output, the three indexes are only 0.96 $,1.24 and 30.67%. The research results show that non-market services of paddy farming contribute significantly to human well-being. Therefore, in order to protect the multi-functionality of paddy farming and achieve the sustainable management,the government should take reasonable measures and make incentive plans.

Sustainable Utilization of Agricultural Land in Chengdu Metropolitan Area Based on Emergy Analysis

[Objectives]This study aimed to analyze the sustainable use of agricultural land in the Chengdu metropolitan area from 2006 to 2016.[Methods]Using Odum's emergy theory,an index system was constructed to evaluate the sustainable use of agricultural land,including total emergy input-output ratio,industrial emergy input-output ratio,environmental load index and sustainable use index of agricultural land based on emergy,to reflect the sustainable use of agricultural land in the Chengdu metropolitan area.The data base was a unified standard that was converted from various types of energy stored and flowing in the agricultural land system of the Chengdu metropolitan area,that is,emergy.[Results]From 2006 to 2016,the total emergy input-output ratio of agricultural land in the metropolitan area fluctuated and decreased,lower than the national average.The industrial emergy input-output ratio was generally in a fluctuating downward trend.The environmental load index of agricultural land in the metropolitan area was lower than the national average.However,it has been on the rise since 2012.During the corresponding period,the sustainable use index of the region also showed a downward trend.[Conclusions]The utilization rate of emergy in this area was low.The dependence of industrial emergy input-output ratio on industrial subsidiary energy and the degree of agricultural mechanization are constantly improving.The environmental resources in this area still have room for accommodation and have not been fully utilized.The sustainable use of agricultural land has been declining.

Emergy-analysis based approaches to develop circular economy in the Three Gorges Reservoir area

The eco-environment and the condition of economic development in the Three Gorges area were evaluated with emergy indices calculated with the statistic data of the years from 1997 to 2005. The rising environmental loading ratio indicates an increasing pressure of economic activities on the environment and the economic development achieved at the cost of over-exploitation of resources and environment deterioration. The net emergy yield ratio implies that the economic system of this area was a self-contained, resource-export-oriented type at a relatively low level of technology. The emergy sustainability index of about 6 implies the economy of this area was under developed but had a potential to grow. According to the results of the emergy analysis, circular economy should be taken as the economic model of this region's development. This economic system should be water-resource-oriented and more open, make combined use of local and extraneous resources, and have an updated systematic structure with emphasis on emergy recirculation.

Simulation Technology of Environmental Impacts by Zero-energy Residential Buildings Based on Emergy Analysis Method

This paper presents a simulation technology of environmental impact for the building. By emergy analysis method,emergy costs of building( or construction engineering) can be calculated in the life cycle. It includes the engineering cost, environmental cost and social cost of building. Through integrating GIS technology with multi-agent technology,life cycle substance and energy metabolism of building( construction engineering) can be simulated and their environmental influence can be dynamically displayed. Based on the case study of entries works‘Sunny Inside'by Xiamen University in 2013 China International Solar Decathlon Competition,we discovered the changing pattern of surrounding environmental impact from waste streams of the zero-energy building and ordinary construction. The simulation results verified and showed the Odum principles of maximum power. This paper provides a new research perspective and integration approach for the environmental impact assessment in building and construction engineering. The result will help decision-making in design and construction engineering scheme.

Emergy Analysis of the Agricultural Eco-economic System in Dongting Lake Area of Hunan Province

[ Objective] The reseamh aimed to discuss eco-efficiency of the agro-ecosystem in Dongting Lake area of Hunan. [ Method] By referring to emergy reseamh method, emergy structure, function and efficiency of the system were analyzed according to emergy input -output data of the system in 2009. [ Result] The system had developed economy, and mechanization and modernization degrees were higher. Emergy output of the system was unbalanced, and market pricing of the agricultural product was significantly lower, especially farming product. Seen from sustainable development index and environmental loading ratio of the system, the system was full of vitality and development potential. The pressure of natural resources and environment was not very great, but the system accommodated too many populations. [ Conclusion] Basic direction of the agricultur- al policy in the zone was further shortening industrial and agricultural price scissors, continuing to implement price protection of the farming product, adjusting agricultural and product structures and transferring surplus labor.

Emergy Analysis of Sustainability of Eco-economic System in Sichuan's Baisha River Valley

Using emergy analysis method,I conduct quantitative analysis of social,economic and natural systems in Sichuan's Baisha River valley during the period 2002-2006,through the establishment of indicators.I compare the emergy of Baisha River valley,with that of Xinjiang's Manas River valley and Sichuan Province,and evaluate the sustainable development conditions in Baisha River valley,in order to provide corresponding reference for the development and utilization of Baisha River valley in the future.The results show that from the perspective of emergy input of economic system,Baisha River valley is a typical ecological and economic zone with rich resources to be developed;in terms of the development of natural conditions and utilization of ecological resources,the resource utilization intensity of Baisha River valley is weak and the environmental loading ratio there is low,thus the level of emergy yield needs to be improved;the system of Baisha River valley has enormous capacity for sustainable development and good potential for development.

Sustainability Analysis of Cropland Use in Cropping-Pastoral Ecotone before and after the Grain-for-Green Policy:A Case Study from Yanchi County in Ningxia

[Objective] This study aimed to analyze the sustainability of cropland use in cropping-pastoral ecotone before and after the Grain-for-Green Policy. [Method] Using Yanchi County in Ningxia Hui Autonomous Region as a case study area, this investigation used the annual transfer rate of land use types, cropland suitability and emergy analysis to examine the major pressures affecting the sustainable use of cropland before and after the Grain-for-Green Policy. [Result] The expansion of con- struction land onto cropland was significant; the annual cropland area was still larger than the land area suitable for cropping after the policy; agrochemical inputs used for crop production gradually increased and unit crop outputs required more agro- chemical inputs. Cropland use sustainability showed a fluctuating downward trend. [Conclusion] The results imply that the protection of high quality cropland, further im- plementation of the policy and control of agrochemical inputs according to precipita- tion are the main measures needed for sustainable cropland use in cropping-pastoral ecotone.

Emergy-based study on eco-economic system of arid and semi-arid region:a case of Gansu province,China

Taking Gansu province as a model case,this study provides an integrated analysis on the eco-economic system of arid and semi-arid region based on emergy synthesis theory. Through calculating the values of renewable emergy flow,non-renewable resources,imported emergy,exported emergy,waste emergy,and total emergy during the period of 1978-2007,the performance of Gansu eco-economic system was analyzed. The results indicated that the renewable emergy flow within the province basically remained steady state which was estimated at 2.99×1022 solar emjoules (sej) from 1978 to 2007. The imported emergy and exported emergy were estimated at 3.75×1017 sej and 2.99×1020 sej in 1978 and increased to 1.07×1022 sej and 1.44×1022 sej respectively in 2007. The nonrenewable emergy flow was estimated at 1.62×1022 sej and increased to 1.85×1023 sej,with annual growth rate of 8.7%,while the estimated total emergy was 4.58×1022 sej in 1978 and increased to 2.11×1023 sej in 2007,with annual growth rate of 5.41%. Our results indicate a deteriorate situation between economic development and environmental protection in the region. The rapid economic growth in the past thirty years was based on a great consumption of nonrenewable resource and caused continuous decrease in the capacity of sustainable development. The environmental loading ratio was 0.53 in 1978,increased to 6.06 in 2007,indicating a rapid degradation of the regional environment quality. We calculated that the actual population was 1.53 times the renewable resource population in 1978,increased to 7.06 times in 2007. During the period of 1978-2007,the emergy rose from 2.45×1015 sej/(capita·a) to 8.07×1015 sej/(capita·a). Our analysis revealed that the emergy density presented a trend of gradual increase,and then the emergy currency ratio in Gansu decreased from 7.08×1013 sej/Chinese Yuan to 7.82×1012 sej/Chinese Yuan.

Urban ecological sustainability assessment of the human-made system and natural system based on emergy and GIS approach

Due to the complexity of sustainable urban research,the environmental sustainability was assessed.Taking the sponge city as an example,the case study was conducted based on the integrated geographic information system(GIS)and emergy methods.The results demonstrate that the emergy of agricultural crops,major industrial products,comprehensive energy products,imports and exports,waste products and increased natural system emergy are the decisive factors for the sustainability assessment.Agricultural crops are the primary contributor,which accounts for 48.9%of the total emergy amount.Urban solid waste has a self-evident superiority in the waste products emergy proportion.Surface water and vegetal biomass emergy possess the pivotal consequences,far higher than soil organic matter.The sewage treatment stations(0.11%)play a small role in the sustainability assessment of the sponge city.The emergy sustainability index is 0.02181,which indicates poor environmental sustainability.According to the study results,increasing renewable energy input proportion and adopting the vegetal biomass of high unit emergy values(UEVs)can improve the sustainability level.

Emergy Evaluation of a Village Ecosystem in Wolong Nature Reserve in China

Due to historic reasons, there are several human settlements in nature reserves and national parks, which may constitute a threat to biodiversity. Establishment of nature reserves may however generate constraints for development of local communities residing in these reserves. The village ecosystem of Zhuanjinglou Village in Wolong Nature Reserve includes population, farming and livestock (domestic and alpine) and forest ecosystem. An emergy analysis of agro-ecosystem (including the farming and livestock ecosystem) and energy consumption in Zhuanjinglou Village indicates that livestock ecosystem plays an important role in village ecosystem, which may be the source of great pressure on the state of the local environment. The increasing ratio of electricity in energy consumption may play a positive role for environmental conservation. Despite some successful experiences, there are some remaining issues that need to be addressed in the ecological rehabilitation of the village ecosystem.

Emergy Analysis of Typical Decentralized Rural Sewage Treatment System: A Case Study of Soil Rapid Infiltration in Qingdao, China

Decentralized sewage treatment systems are commonly used in rural areas of China because these systems are low cost, easy maintenance and high efficiency. However, as awareness of the importance of sus- tainable development has increased, questions concerning how to evaluate the sustainability of these systems has become a key point. In this study, emergy analysis is applied to evaluate the soil rapid infiltration for a decentralized rural sewage treatment plant that is located in Dongzhuangtou village, Qingdao, China. The results show that the environmental load ratio and the emergy sustainability index of the system are 0.07 and 242.88, respectively. The net economic benefit is 2.17E＋18 sej·year^-1 when converted into solar emjoule. Compared to other treatment systems, the environmental load ratio of the system is lower, and the emergy sustainability index is higher. This study reveals the reuse of treated water can produce great economic benefits in the soil rapid infiltration system. The environmental impact of the system is lower, and the sustainability is higher than that of other treatment systems. This result provides a quantitative evaluation of the sustainable development of rural sewage treatment systems in China.

Construction and Application of Soil Erosion Control and Circular Agriculture Mode in Hilly Red Soil of Southern China

[Objective] The paper was to construct soil erosion control and circular agriculture mode in hilly red soil of southern China, and analyze its application effort. [Method] The cause of soil erosion in hilly red soil of southern China and the reason for long-term treatment without remarkable effort were analyzed. On this basis, the key technology, economic benefit, ecological service function and carbon sequestration sink enhancement effect of various modes were further analyzed. [Result] The basic idea for comprehensive control of hilly soil erosion in southern China was as follows: the control of soil erosion was combined with modern agricultural production, in order to build "fruit(tea)-grass-livestock-methane" circular agriculture mode with comprehensive control of soil erosion; application effect analysis showed that the establishment of circular agriculture mode in southern hilly area to control soil erosion had remarkable effect, which could simultaneously meet the coordinated development of ecological, economic and social benefits. [Conclusion] This study established an effective mode suitable for soil erosion control and agricultural protection development in southern red soil mountain, which could drive the sustainable development of ecological restoration of mountainous area and rural agricultural economy.

Sustainability Assessment and Land Use Optimization of Oasis Agro-economic System Based on Emergy Analysis

Oases are important habitats for human survival and development in northwest arid China;however, they are fragile. To realize ecological construction and sustainable development in northwest China, an analysis of the economic and ecological benefits of the oasis system with a focus on sustainability and land use optimization of oasis agro-economic systems are needed. This paper selects Fukang City as a study area. It is located on the northern slope of Mt Tianshan, Xinjiang Uygur Autonomous Region. The authors discuss the ecological and economic benefits of the oasis system, annual variation and establish an optimized allocation scheme of oasis land use structure in Fukang City based on emergy analysis and linear programming modeling. From 1996 to 2006 the oasis system was in a weak sustainable development state. Ecological and economic benefits analysis of the oasis system based on emergy analysis shows that the development of an oasis system in Fukang City is restricted by land, climate and water resources, being a typical example of the high-input and low-output type. The comparative advantage analysis of oasis cropping based on economics and ecological economics shows that the farming structure will vary across different goals. If the maximum ecological efficiency is pursued, farming structure is determined by emergy density;and if the maximum ecological and economic benefits with limited water resources are pursued, farming structure is determined by the emergy value per unit area of irrigation.

Emergy Based Sustainability Scenario Analysis of Oasis Agricultural Systems: A Case Study from Xinjiang, China

How to coordinate arid eco-environmental protection and oasis agricultural development and avoid desertification is a key problem in achieving the sustainable development of oasis human- earth systems. We analyzed the temporal characteristics and overall tendency of an arid oasis agricultural production system in Yining County, China by means of emergy methods and ternary diagrams theory. From 1989–2008, total emergy input and output of the oasis agricultural system in Yining County had a trend of sustainable development. According to the sustainability analysis with emergy indices, the agricultural production systems in Yining County were still at a sustainable status. However, the emergy-based sustainability index （ESI） followed a decreasing trend. Scenario analysis of the sustainability lines based on ternary diagrams showed that both the F （input from economic component） and N （input from nonrenewable resource） leading modes had limitations in the study case. The agricultural production of Yining County should adopt the R leading mode, in which the percentage of non-renewable resources in the local system will be kept roughly unchanged, while the fraction of purchased inputs and renewable resources will be decreased in synchronism. In this way, the contribution from local renewable resources to agricultural production will be increased, and sustainable development ensured.

Construction of Energy Diagram of Ecological High-value Agriculture System and Emergry Evaluation Index System

Ecological high-value agriculture research, ecological high-value agricultural is the future of agriculture in China. In the emergy diagram was constructed based on emergy theory, and the mechanism and realization approach were well described. In addition, a set of evaluation index system of emergy was established to deter- mine contribution made by different resources of the system, providing references for further exploration of ecological high-value agricultural production system.

EMERGY analysis for sustainability evaluation of the Baiyangdian wetland ecosystem in China

t This study presents a quantitative and ecological benefit evaluation of the Baiyangdian wetland in China between the years 2000 and 2006.Methods of EMERGY analysis were applied to illustrate the wetland ecosystem,to evaluate the economic and environmental inputs and consequent yields,and to assess the sustainability of the Baiyangdian wetland.The indicators for the integrated ecological and economic system,such as EMERGY yield ratio(EYR)(7.51),EMERGY investment ratio(EIR)(4.52),environmental loading ratio(ELR)(2.92),EMERGY exchange ratio(0.41),and EMERGY sustainable indicator(ESI)(2.57)were calculated,compared,analyzed,and discussed.The non-renewable investment in Baiyangdian was greater than renewable investment,leading to the unsustainable development of the system.High EYR indicated that the Baiyangdian integrated system had created huge profits for its people,while ELR and ESI revealed that human behavior has been a heavy burden on the environment,and countermeasures should be taken by the Chinese government to relieve and resolve these problems.Potential management methods were also proposed in this paper.

Research on the Sustainability of Afghanistan Based on the Emergy Analysis

Afghanistan is an important country for the Silk Road Economic Belt and the 21 st Century Maritime Silk Road（the Belt and Road） proposed by China. Due to years of war,Afghanistan is not well-developed economically. However,Afghanistan has abundant mineral resources and unique geographical advantages that are of far-reaching significance for Chinese economic strategic development. To investigate the sustainability of the eco-economic system of Afghanistan,we completed a quantitative evaluation of the emergy of Afghanistan during the period 2008 to 2015 by establishing an indicator system based on an emergy analysis. Results showed that from 2008 to 2015,the total emergy used of Afghanistan increased from 5.56×10^（22） sej to 9.75×10^（22） sej,among which the proportion of non-renewable emergy was less than 25.7%. This indicates that local resources in Afghanistan have yet to be exploited and utilized effectively and that its economic development relied heavily on the input of external resources. Meanwhile,the Emergy Sustainability Index（ESI） of Afghanistan from 2008 to 2015 dropped from 3.00 to 0.72,the Environmental Loading Ratio（ELR） increased from 0.77 to 2.06,and the Emergy Yield Ratio（EYR） dropped from 2.31 to 1.49,reflecting the imbalanced utilization of resources and the low level of economic development in Afghanistan. As a result,the potential for sustainable development of Afghanistan is relatively great. Basic infrastructure construction and reasonable exploitation of natural resources are the urgent needs.

A new approach to natural capital sustainable development

The three-dimension(3D) ecological footprint makes the analysis of the relationships between the demand and supply of natural capital more credible by importing footprint depth and footprint size.This article used China's regions as the object to analyze the high-level sustainability of the natural capital from the view of "ecology-efficiency-fairness" multidimensional framework.Research showed that China's ecological footprint has risen while bio-capacity per capita has descended in recent 20 years.This paper also discusses the spatial distribution of China's natural capital ecological sustainability,efficiency sustainability and fairness sustainability.Finally,it builds multi-criteria evaluation(MCE) models to get multidimensional sustainability framework taking ecological sustainability,efficiency sustainability,and fairness sustainability into consideration.