Assessing life cycle impacts from changes in agricultural practices of crop production
Assessing life cycle impacts from changes in agricultural practices of crop production
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评估作物生产农业实践变化对生命周期的影响
DOI：
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
M. Bentham
中科院分区：
文献类型：
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作者：
J. Kløverpris;Claus Nordstrøm Scheel;J. Schmidt;B. Grant;W. Smith;M. Bentham
本文提出了一种改进的方法，研究生命周期的影响（特别是全球变暖），从作物生产实践的变化。该文件力求通过更好的工具改进定量评估，并力求将结果分成逻辑上独立的类别，从而易于向农民和其他相关利益攸关方群体解释。的方法框架说明了在美国玉米生产中引入磷酸盐接种剂的具体研究。该框架考虑了在农田A上从最初的农业做法（参考系统）向替代做法（替代系统）的转变。为确保系统等效性（相同的功能产出），替代系统在其他地方扩大替代或诱导作物生产，以平衡A区作物产量的潜在变化。上游效应是根据A区农业投入的变化来分析的。产量效应通过评估其他地区作物产量变化的影响来量化。通过生物地球化学建模量化了来自现场的直接排放潜在变化的现场效应。下游影响被评估为收获后处理的潜在变化的影响，例如，干燥要求的变化（如果作物湿度发生变化）。在明尼苏达州，一种土壤真菌拜莱青霉（Penicillium bilaiae）的接种剂可以使玉米产量增加0.44 Mg ha−1（约4%）。对于全球变暖，上游效应（接种物生产）为每公顷处理0.4公斤二氧化碳当量。田间效应（通过土壤地球化学模型DayCent估算）为− 250 kg CO2 e ha−1（土壤碳增加，N2 O排放减少），产量效应（通过简单系统扩展估算）为− 140 kg CO2 e ha−1（玉米生产转移到其他地方）。没有下游效应。每生产一毫克干玉米的总变化为-36千克CO2当量，相当于全球变暖影响减少14%。结合更先进的方法表明，结果可能在每毫克玉米-27至-40千克CO2 e之间变化。本文件说明了农业做法变化对环境的影响如何按照其在生命周期中发生的位置进行逻辑分类。该文件还说明了如何直接从外地（现场效应）的排放量的变化，可以评估地球化学建模，从而提高生命周期清单建模和解决文献中的问题。建议在农业实践变化的任何LCA中使用所提出的方法。
This paper presents an improved methodological approach for studying life cycle impacts (especially global warming) from changes in crop production practices. The paper seeks to improve the quantitative assessment via better tools and it seeks to break down results in categories that are logically separate and thereby easy to explain to farmers and other relevant stakeholder groups. The methodological framework is illustrated by a concrete study of a phosphate inoculant introduced in US corn production. The framework considers a shift from an initial agricultural practice (reference system) to an alternative practice (alternative system) on an area of cropland A. To ensure system equivalence (same functional output), the alternative system is expanded with displaced or induced crop production elsewhere to level out potential changes in crop output from the area A. Upstream effects are analyzed in terms of changes in agricultural inputs to the area A. The yield effect is quantified by assessing the impacts from changes in crop production elsewhere. The field effect from potential changes in direct emissions from the field is quantified via biogeochemical modeling. Downstream effects are assessed as impacts from potential changes in post-harvest treatment, e.g., changes in drying requirements (if crop moisture changes). An inoculant with the soil fungus Penicillium bilaiae has been shown to increase corn yields in Minnesota by 0.44 Mg ha−1 (~ 4%). For global warming, the upstream effect (inoculant production) was 0.4 kg CO2e per hectare treated. The field effect (estimated via the biogeochemical model DayCent) was − 250 kg CO2e ha−1 (increased soil carbon and reduced N2O emissions) and the yield effect (estimated by simple system expansion) was − 140 kg CO2e ha−1 (corn production displaced elsewhere). There were no downstream effects. The total change per Mg dried corn produced was − 36 kg CO2e corresponding to a 14% decrease in global warming impacts. Combining more advanced methods indicates that results may vary from − 27 to − 40 kg CO2e per Mg corn. The present paper illustrates how environmental impacts from changes in agricultural practices can be logically categorized according to where in the life cycle they occur. The paper also illustrates how changes in emissions directly from the field (the field effect) can be assessed by biogeochemical modeling, thereby improving life cycle inventory modeling and addressing concerns in the literature. It is recommended to use the presented approach in any LCA of changes in agricultural practices.