基于生命周期评价的现代“草-羊-田”农牧循环系统调控

Regulation of modern“straw-sheep-cropland”agro-pastoral system using life cycle assessment

现代循环农业是实现农业绿色发展、推进乡村全面振兴的重要途径。但以农户经验构建而成的传统循环农业系统多缺乏精确的数据支持与参数匹配,使得系统的高效循环运行面临挑战。因此,本研究在数据采集与跟踪调研的基础上,采用生命周期评价对现代"草-羊-田"农牧循环系统进行实证研究,通过特征化、标准化与加权评估分析不同类别潜在环境影响,并计算系统模拟调控前后污染降级所需环境服务能。结果表明,饲料加工与湖羊养殖亚系统所产生的各类潜在环境影响都超过了其类别总影响的85%,远高于粮食种植和有机堆肥亚系统的;人体毒性和水体生态毒性在各亚系统中所产生的环境影响都较大,而陆地生态毒性的均最小。为实现污染降级每年所需空气、水体和土壤的环境服务能分别为7.42×10^(10)、6.03×10^(16)和1.59×10^(12)J;通过耦合参数协调和关键技术优化对系统进行模拟调控,经测算与原系统相比每年所需各项环境服务能分别降低52%、44%和21%。该研究基于生命周期评价形成的适用于现代"草-羊-田"农牧循环系统并指导其整体调控的方法体系,对现代农牧循环系统的可持续发展与复制推广具有指导意义,同时可为其他现代循环农业系统的优化调整提供方法参考。

Modern circular agriculture aims to minimize the number of external outputs for less impact on the environment in the complex ecosystem and the circular economy of the industry chains.Therefore,the green development of agriculture can be achieved to promote rural revitalization in China.However,accurate data support and parameter matching are still lacking in most operation of circular agriculture.Fortunately,the life cycle assessment can serve as an effective tool to evaluate the environmental impact of the entire chains in the product systems,further improving the circulating efficiency of the systems in recent years.In this study,an empirical investigation using the life cycle assessment was performed on the modern“straw-sheep-cropland”agro-pastoral system located in the northeast of Suzhou,Jiangsu Province,China.Six types of potential environmental impacts were evaluated from the sufficient data collection and tracking survey using the data characterization,standardization,and weighted summation,including the acidification potential,global warming potential,terrestrial ecotoxicity,human toxicity,freshwater aquatic ecotoxicity,and eutrophication potential.And then the environmental service energy was compared for the emission degradation before and after the regulation.The energy was calculated to consume the pollution dilution for a safe concentration.The results showed that fertilization was an important factor in the environmental performance of the cereal cropping subsystem during the wheat-and rice-growing seasons.The types of potential environmental impacts from the feed producing and sheep raising subsystems were more than 85%of the total impacts,which were much higher than that of the cereal cropping and organic composting subsystems.The environmental impacts of human toxicity and freshwater aquatic ecotoxicity were greater in each subsystem,whereas,that of terrestrial ecotoxicity was the least.After life cycle assessment,the annual environmental service energies of air,water,and soil to realize the emission degradation were 7.42×10^(10),6.03×10^(16),and 1.59×10^(12)J,respectively,according to the threshold concentration of index pollutants.Subsequently,the scales of feed producing and organic composting subsystems were adjusted in line with the matching output with the input of successive subsystems,particularly under the steady production scale of cereal cropping and sheep raising subsystems.A simulated regulation was also conducted to optimize the parameters and key technologies.It was estimated that the annual environmental service energies of air,water,and soil were reduced by 52%,44%,and 21%,respectively,compared with the original.In conclusion,a new system was formed with excellent sustainability and replication to evaluate and regulate the modern agro-pastoral system using the life cycle assessment.The finding can provide a strong reference for the optimal regulation of modern agricultural systems in diverse regions.In the future research,the local life cycle inventory database can be constructed for the life cycle assessment.