农业生产系统的温室气体(GHG)足迹,亦即形成单位农产品的生命周期GHG净排放量,是一个衡量农业生产影响气候变化潜势的指标,也是为了减缓气候变暖而确定食品绿色增值税率的关键参数.然而,当前农作物种植系统的GHG足迹定量却还存在突出问题或不足,如绝大多数研究都忽略土壤有机碳库变化而致使GHG足迹数据不具可靠性等.鉴于此,本文提出农作物种植系统GHG足迹的通用定量方法,并汇集了一些分量源自文献的GHG排放系数值,且对于发生在田间的主要分量,特别强调了直接观测和过程模型模拟相结合确定其GHG排放(或吸收)系数的必要性.此外,还指出未来进一步扩展该方法的必要性,尤其应当使其能够适用于农作物-畜牧养殖复合生产系统.%The greenhouse gas (GHG) footprint of an agricultural system is a measure of the climate change impact potential (CCIP) exerted by the formation of its product(s).Its accurate quantification is essential for determining the green value added tax of agricultural products for food markets,which in turn may drastically change the current patterns of food consumption and production towards a product life cycle oriented economy.This paper reviews the literature regarding GHG footprints of crop cultivation systems.The review concludes that few studies have fully considered the categories/ items of net GHG emissions from an investigated crop cultivation system,and thus probably led to biases in footprint estimation.Most studies to date have even neglected changes in the soil organic carbon stocks of ecosystems with annual crops,while process-oriented biogeochemical models so far have seldom been involved in GHG footprint quantification.To help with solving these problems or drawbacks,the authors propose a generic methodological framework for quantifying GHG footprints of crop cultivation systems free from grazing,which takes into account all direct/indirect GHG contributors within a "cradle-to-gate" life cycle.The authors then provide example values of some GHG emission factors,such as those from machinery operations and other agricultural inputs,extracted from the literature.In addition,direct measurements or model simulations of other major on-farm emission factors are emphasized.The need to further update this methodological framework in future studies,especially by adapting it to mixed crop-livestock production systems,is also indicated.
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机译：农业生产系统的温室气体(GHG)足迹,亦即形成单位农产品的生命周期GHG净排放量,是一个衡量农业生产影响气候变化潜势的指标,也是为了减缓气候变暖而确定食品绿色增值税率的关键参数.然而,当前农作物种植系统的GHG足迹定量却还存在突出问题或不足,如绝大多数研究都忽略土壤有机碳库变化而致使GHG足迹数据不具可靠性等.鉴于此,本文提出农作物种植系统GHG足迹的通用定量方法,并汇集了一些分量源自文献的GHG排放系数值,且对于发生在田间的主要分量,特别强调了直接观测和过程模型模拟相结合确定其GHG排放(或吸收)系数的必要性.此外,还指出未来进一步扩展该方法的必要性,尤其应当使其能够适用于农作物-畜牧养殖复合生产系统.%The greenhouse gas (GHG) footprint of an agricultural system is a measure of the climate change impact potential (CCIP) exerted by the formation of its product(s).Its accurate quantification is essential for determining the green value added tax of agricultural products for food markets,which in turn may drastically change the current patterns of food consumption and production towards a product life cycle oriented economy.This paper reviews the literature regarding GHG footprints of crop cultivation systems.The review concludes that few studies have fully considered the categories/ items of net GHG emissions from an investigated crop cultivation system,and thus probably led to biases in footprint estimation.Most studies to date have even neglected changes in the soil organic carbon stocks of ecosystems with annual crops,while process-oriented biogeochemical models so far have seldom been involved in GHG footprint quantification.To help with solving these problems or drawbacks,the authors propose a generic methodological framework for quantifying GHG footprints of crop cultivation systems free from grazing,which takes into account all direct/indirect GHG contributors within a "cradle-to-gate" life cycle.The authors then provide example values of some GHG emission factors,such as those from machinery operations and other agricultural inputs,extracted from the literature.In addition,direct measurements or model simulations of other major on-farm emission factors are emphasized.The need to further update this methodological framework in future studies,especially by adapting it to mixed crop-livestock production systems,is also indicated.
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