中国油料作物能源利用效率与温室气体排放

Energy use efficiency and greenhouse gas emissions of oil crops in China

  • 摘要: 作物生产中有效利用能源是可持续农业的一个重要目标。中国作为油料生产和消费大国, 在其生产过程中, 减少过度无效能源消耗, 优化能源利用结构, 提高能源利用效率, 对于农民节本增收、降低温室气体排放和环境影响具有重要意义。本文基于生命周期分析(LCA)视角, 采用生命周期评价和数据包络分析(DEA)方法, 对油菜、大豆、花生3种油料作物能源利用效率和温室气体排放进行了测算, 分析了不同省份能源高效和低效利用的原因, 探究了各省能源节约和温室气体减排的可能性与潜力。结果表明: 1) 3种油料作物生产系统单位能量消耗的产出能力差异不显著, 但能源利用效率差异显著, 呈花生>油菜>大豆的特点。2) 3种油料作物中, 花生温室气体排放量最高874.96 kg(CO2 eq)∙hm−2, 其次为油菜660.16 kg(CO2 eq)∙hm−2, 大豆最低507.07 kg(CO2 eq)∙hm−2; 不同油料作物物质投入和农事操作温室气体排放贡献差异明显, 油菜与花生种植主要温室气体排放源为化肥, 而大豆种植过程中化肥、柴油、灌溉温室气体排放贡献相对均衡。3)油料作物能源利用优化和温室气体减排潜力较大, 油菜、大豆、花生低效省份能源利用优化后, 分别可节约11.97%、16.38%和15.89%的资源, 可减排20.60~616.32 kg(CO2 eq)∙hm−2。因此, 根据区域实际情况, 优化能源低效利用地区的能源利用结构, 探寻产量与碳排双优的生产模式, 对推动油料作物种植节本增收与绿色发展将发挥重要作用。

     

    Abstract: Energy is a major component in enhancing agricultural productivity. Accounting for energy efficiency at the production stage of crop is essential for achieving sustainable agriculture. Due to the high level of production and consumption of oil in China, it is of great importance to pay attention to energy consumption and its negatively environmental impacts in the oil production process. Measures of optimizing energy utilization structure, reducing excessive and ineffective energy consumption and improving energy utilization efficiency can be used, in order to increase income, save cost and reduce greenhouse gas emissions synthetically. Academically, a large number of previous studies have contributed to energy use and environmental impacts in the production of oil crops, fruits, vegetables, and food crops on various scales. However, there is a lack of studies related to energy use efficiency and greenhouse gas emissions in oil production which concentrate in major oil crops production areas nationally so far. Generally, in terms of models used in relevant study areas, methods including life cycle assessment (LCA), data envelopment analysis (DEA), process analysis, energy analysis have been used commonly, which provide valuable references to the present study. Given that oil crops production is inherently a life process, this paper combined LCA+DEA methods to estimate the energy utilization efficiency and greenhouse gas emissions of oil crops, which helped to rank efficient and inefficient provincial production units. In further, the underlying reasons which caused inefficient energy use were deeply identified in different provinces. Additionally, for purpose of practical application, this paper explored the possibility and potential of energy saving and GHG emission reduction in each province. The results showed as follows. 1) There was no significant difference in the output capacity per unit energy consumption among the three studied oil crop systems. However, the energy use efficiency of three oil crops displayed remarkably differently, which showed peanut > oilseed rape > soybean. 2) Among the three oil crops, peanut had the highest GHG emissions 874.96 kg(CO2 eq)∙hm−2, followed by oilseed rape 660.16 kg(CO2 eq)∙hm−2 and soybean 507.07 kg(CO2 eq)∙hm−2. In addition, the contributions of substantiality inputs and agricultural operations to GHG emissions varied greatly from different oil crops. Specifically, the significant GHG emission source of oilseed rape and peanut was fertilizer. Nevertheless, contribution of fertilizer, diesel fuel and irrigation to the GHG emissions of soybean showed less difference. 3) There was great potential for energy utilization optimization and GHG emission reduction. Estimates resulted from this study displayed that about 11.97%, 16.38% and 15.89% of resources invested to oilseed rape, soybean and peanut in inefficient provinces could be saved respectively, which were capable of reducing 20.60−616.32 kg(CO2 eq)∙hm−2 GHG emissions as well. Therefore, it is necessary to optimize the energy utilization structure of low efficiency areas according to the actual situation, and explore the production mode of double optimal yield and carbon emissions. This will play an important role in saving money and increasing income for regional oilseed cultivation, as well as green development.

     

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