Greenhouse gas, water, and land footprint per unit of production of the California dairy industry over 50 years.
Greenhouse gas, water, and land footprint per unit of production of the California dairy industry over 50 years.
复制标题
加州乳制品行业 50 年来每单位产量的温室气体、水和土地足迹。
DOI：
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发表时间：
2020
影响因子：
3.5
通讯作者：
E. Kebreab
中科院分区：
文献类型：
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作者：
A. Naranjo;A. Johnson;H. Rossow;E. Kebreab
包括乳制品在内的食品生产与环境影响和资源使用有关，当按单位产品进行调整时，这种影响和资源使用一直在稳步改善。本研究的目的是对加州乳制品生产系统进行从摇篮到农场的环境影响分析和资源清查，以估计1964年至2014年50年间温室气体排放以及水和土地利用的变化。根据国际标准和联合国粮食及农业组织的指导方针，使用生命周期评估，我们分析了加州乳制品生产对全球环境变化的贡献。2014年，在加州生产1公斤能量和蛋白质校正牛奶（ECM）排放1.12至1.16公斤二氧化碳当量（CO2 e），而1964年为2.11公斤CO2 e，在过去50年中减少了45.0%至46.9%，具体取决于所使用的模型。肠内甲烷强度的更大降低（即，与1964年相比，2014年观察到每千克ECM的甲烷产量（减少54.1至55.7%）与粪便温室气体（减少8.73至11.9%）相比。这主要是因为该州的粪肥管理依赖于泻湖储存，其甲烷转化系数大于固体粪肥储存。用水强度降低了88.1 - 89.9%，作物生产用水减少了88.7 - 90.5%，住房和挤奶用水减少了55.3 - 59.2%，自由水摄入量减少了52.4 - 54%。改进作物遗传学和管理有助于提高水资源利用效率。与1964年相比，2014年作物生产的土地需求减少了89.4%至89.7%。这主要是由于在过去50年中农作物产量的大幅增加。通过基因改良、更好的营养和动物护理，每头奶牛的产奶量增加，有助于减少温室气体排放以及按单位生产（密度）计算的土地和水的使用。
Food production including dairy has been associated with environmental impacts and resource use that has been steadily improving when adjusted per unit of product. The objective of this study was to conduct a cradle-to-farm gate environmental impact analysis and resource inventory of the California dairy production system to estimate the change in greenhouse gas emissions and water and land use over the 50-yr period between 1964 and 2014. Using a life cycle assessment according to international standards and the Food and Agriculture Organization of the United Nations guidelines, we analyzed contributions from dairy production in California to global environmental change. Production of 1 kg of energy- and protein-corrected milk (ECM) in California emitted 1.12 to 1.16 kg of CO2 equivalents (CO2e) in 2014 compared with 2.11 kg of CO2e in 1964, a reduction of 45.0 to 46.9% over the last 50 yr, depending on the model used. Greater reductions in enteric methane intensity (i.e., methane production per kilogram of ECM) were observed (reduction of 54.1 to 55.7%) compared with manure GHG (reduction of 8.73 to 11.9%) in 2014 compared with 1964. This was mainly because manure management in the state relies on lagoons for storage, which has a greater methane conversion factor than solid manure storage. Water use intensity was reduced by 88.1 to 89.9%, with water reductions of 88.7 to 90.5% in crop production, 55.3 to 59.2% in housing and milking, and 52.4 to 54% in free water intake. Improved crop genetics and management have contributed to large efficiencies in water utilization. Land requirements for crop production were reduced by 89.4 to 89.7% in 2014 compared with 1964. This was mainly due to dramatic increases in crop yields in the last 50 yr. The increases in milk production per cow through genetic improvements and better nutrition and animal care have contributed to reductions in greenhouse gas emissions and land and water usage when calculated per unit of production (intensity) basis.