Pasture Systems and Watershed Management Research Unit, USDA-Agricultural Research Service, Building 3702 Curtin Rd., University Park, PA 16802-3702.
Pasture Systems and Watershed Management Research Unit, USDA-Agricultural Research Service, Building 3702 Curtin Rd., University Park, PA 16802-3702.
J Dairy Sci. 2020 Apr;103(4):3275-3288. doi: 10.3168/jds.2019-17388. Epub 2020 Jan 31.
A comprehensive, yet in depth, assessment is needed of the environmental impacts of dairy farms at regional and national scales to better track improvements made by the industry. With Pennsylvania as an example, a method using process-level simulation and cradle-to-farm gate life cycle assessment was developed and used to assess important environmental footprints of dairy farms within a state. Representative dairy farms of various sizes and management practices throughout 7 regions of the state were simulated with the Integrated Farm System Model. Environmental footprints varied widely among farms, with this variation influenced primarily by soil characteristics and climate and secondarily by farm management. Therefore, prescriptive mitigation strategies for individual farms are more effective than uniform enforcement of specific strategies across the state. Footprints for the whole state were determined by totaling values among farms and regions based on the amounts of milk produced by each. Pennsylvania dairy farms were determined to emit 4,555 with an uncertainty of ±415 Gg of CO equivalent of greenhouse gas with an intensity of 0.99 ± 0.09 kg of CO equivalent/kg of fat- and protein-corrected milk (FPCM) produced. Fossil energy consumption was 12,324 ± 1,946 TJ or 2.69 ± 0.42 MJ/kg of FPCM. Blue (nonprecipitation) water consumption was 64.1 ± 13.5 Tg with an intensity of 14.0 ± 3.0 kg/kg of FPCM. A total of all forms of reactive N loss was 43.2 ± 5.0 Gg with an intensity of 9.4 ± 1.1 g/kg of FPCM. These metrics were equivalent to 1.6% of the greenhouse gas emissions, 0.4% of fossil energy use, and 0.8% of fresh water consumption reported for the state. Thus, greenhouse gas emissions, fossil energy use, and blue water use associated with dairy farm production are relatively small compared with total estimates for the state. Perhaps the greatest environmental concern is that of ammonia emission, where dairy farms accounted for about half the estimated emissions of the state. This method can be applied to assessments of the dairy industry at larger regional and national scales.
需要对奶牛场的环境影响进行全面深入的评估，以便更好地跟踪该行业的改进情况。以宾夕法尼亚州为例，开发了一种使用过程水平模拟和摇篮到农场门生命周期评估的方法，并用于评估该州内奶牛场的重要环境足迹。该州 7 个地区的各种规模和管理实践的代表性奶牛场都使用综合农场系统模型进行了模拟。农场之间的环境足迹差异很大，这种差异主要受土壤特征和气候的影响，其次受农场管理的影响。因此，针对个别农场的规定性缓解策略比在全州范围内强制执行具体策略更为有效。根据每个农场生产的牛奶量，通过对农场和地区之间的数值进行加总，确定全州的足迹。宾夕法尼亚州奶牛场排放了 4555 千克二氧化碳当量的温室气体，不确定性为±415 克，温室气体排放强度为每公斤脂肪和蛋白质校正奶（FPCM）的 0.99 ± 0.09 千克二氧化碳当量。化石能源消耗为 12324 ± 1946 太焦耳或 2.69 ± 0.42 兆焦耳/公斤 FPCM。蓝水（非降水）消耗量为 64.1 ± 13.5 太克，强度为每公斤 FPCM 14.0 ± 3.0 千克。所有形式的活性氮损失总量为 43.2 ± 5.0 克，强度为每公斤 FPCM 9.4 ± 1.1 克。这些指标相当于该州报告的温室气体排放量的 1.6%、化石能源使用量的 0.4%和淡水资源使用量的 0.8%。因此，与全州的估计值相比，奶牛场生产的温室气体排放、化石能源使用和蓝水使用相对较小。也许最大的环境问题是氨排放，奶牛场约占该州估计排放量的一半。该方法可应用于更大区域和国家规模的乳制品行业评估。
