Harrison Brad P, Dorigo Martina, Reynolds Christopher K, Sinclair Liam A, Tranter Ricard B, Ray Partha P
Department of Animal Sciences, School of Agriculture, Policy and Development, University of Reading, United Kingdom.
Dairy, Agriculture and Horticulture Development Board, Stoneleigh Park, Kenilworth, Warwickshire, United Kingdom.
PLoS One. 2025 Mar 26;20(3):e0319919. doi: 10.1371/journal.pone.0319919. eCollection 2025.
Mitigating environmental phosphorus loading (EPL) from dairy farms reduces water pollution and improves the sustainability of production. Studies generally simulate EPL from dairy farms using a representative farm type from existing databases. However, housed and pasture-based dairy farming systems might contribute to eutrophication differently and have a varied feasibility of implementing mitigation. This study is the first that quantified EPL from dairy farms using data for FARMSCOPER collected from farmers and comparing EPL and identifying a least-cost suite of mitigation methods. Structural characteristics of 27 dairy farms in Great Britain (GB) were collected. Annual EPL from each farm was simulated in FARMSCOPER under three scenarios. Mean EPL of the production systems was compared to investigate any relationship between EPL and average 305 day adjusted milk yield of cows on each farm. A least-cost suite of mitigation methods was optimised for two model farms to represent either a housed or pasture-based system. Across both systems, 'current' implementation of mitigation methods was simulated to have reduced EPL from 0.63 to 0.56 kg P/ha (11%). The 'current' EPL positively correlated with milk production on a kg and kg/ha basis (P ≤ 0.001 and P = 0.033, respectively). Farms operating a housed system had a mean 'current' EPL that was 59% greater than the pasture-based system though not significant (P = 0.316). This was partly due to a small sample size and because FARMSCOPER's estimates exclude variations in farm practices (i.e., feeding). EPL was reduced by ~ 50% and ~ 60% without incurring annual financial losses by implementing existing mitigation methods for pasture-based and housed systems, respectively. This study highlights the importance of mitigating EPL from GB dairy farming, especially considering the increasing number of higher yielding herds and housed production systems. Furthermore, emphasis should be on increasing implementation of system-specific mitigating methods; efforts to include more recent and specific farm data to improve the FARMSCOPER tool will benefit this.
减轻奶牛场的环境磷负荷（EPL）可减少水污染并提高生产的可持续性。研究通常使用现有数据库中的代表性农场类型来模拟奶牛场的EPL。然而，舍饲和牧场型奶牛养殖系统对富营养化的贡献可能不同，并且实施缓解措施的可行性也各不相同。本研究首次使用从农民那里收集的FARMSCOPER数据对奶牛场的EPL进行量化，并比较EPL并确定一套成本最低的缓解方法。收集了英国（GB）27个奶牛场的结构特征。在三种情景下，使用FARMSCOPER模拟了每个农场的年度EPL。比较了生产系统的平均EPL，以研究EPL与每个农场奶牛的平均305天校正产奶量之间的关系。针对两个模型农场优化了一套成本最低的缓解方法，以分别代表舍饲或牧场型系统。在这两种系统中，模拟缓解方法的“当前”实施情况可使EPL从0.63千克磷/公顷降至0.56千克磷/公顷（11%）。“当前”EPL与千克和千克/公顷基础上的牛奶产量呈正相关（分别为P≤0.001和P = 0.033）。经营舍饲系统的农场的平均“当前”EPL比牧场型系统高59%，但不显著（P = 0.316）。这部分是由于样本量小，并且FARMSCOPER的估计排除了农场实践（即饲养）的差异。通过分别对牧场型和舍饲系统实施现有的缓解方法，EPL分别降低了约50%和约60%，且不会造成年度财务损失。本研究强调了减轻英国奶牛养殖EPL的重要性，特别是考虑到高产牛群和舍饲生产系统数量的增加。此外，应强调增加特定系统缓解方法的实施；努力纳入更新的特定农场数据以改进FARMSCOPER工具将对此有益。
