Reitmeier Heidi, Pease Lindsay, Loss Peyton, Radatz Tim
Department of Soil, Water, and Climate, Northwest Research & Outreach Center, University of Minnesota, Twin Cities, Crookston, Minnesota, USA.
Minnesota Discovery Farms, Minnesota Agricultural Water Resources Center, Eagan, Minnesota, USA.
J Environ Qual. 2025 Jul-Aug;54(4):827-837. doi: 10.1002/jeq2.20635. Epub 2024 Oct 8.
Supported by the National Phosphorus (P) Research Project led by Dr. Andrew Sharpley, Minnesota developed its statewide P-Index, the Minnesota P Loss Index (MNPI), to manage critical source areas of agricultural P. The MNPI has remained unchanged since its last revision in 2006. The overall goal of this study was to critically evaluate the MNPI to determine, in the parlance of Sharpley, if the MNPI remains "directionally and magnitudinally correct." Observed P loss from 67 site-years of annual edge-of-field data was compared with MNPI-predicted P loss. Our assessment indicates that MNPI performance is directionally correct: it correctly ranks fields that are more at risk than others. The MNPI performed better in years with high-intensity rainfall events. Averaging MNPI assessment across multiple years of data input, along with minor adjustments to the calculation algorithm, improved the robustness of MNPI estimates. Continued re-evaluation of the MNPI will ensure that this important tool for nutrient management is properly evaluating P loss potential. This study reflects Dr. Sharpley's decades-long effort to improve and revise P indices so that they reflect advances in the science and management of agricultural P.
在由安德鲁·夏普利博士领导的国家磷（P）研究项目的支持下，明尼苏达州制定了全州范围的磷指数——明尼苏达磷流失指数（MNPI），以管理农业磷的关键源区。自2006年上次修订以来，MNPI一直保持不变。本研究的总体目标是对MNPI进行严格评估，用夏普利的话来说，就是确定MNPI是否仍然“在方向和量级上正确”。将67个站点年的田间边缘年度数据观测到的磷流失与MNPI预测的磷流失进行了比较。我们的评估表明，MNPI的表现方向正确：它能正确地对风险较高的田地进行排名。MNPI在降雨强度大的年份表现更好。对多年数据输入的MNPI评估进行平均，以及对计算算法进行微小调整，提高了MNPI估计的稳健性。持续对MNPI进行重新评估将确保这个营养管理的重要工具能够正确评估磷流失潜力。这项研究反映了夏普利博士数十年来为改进和修订磷指数所做的努力，以便它们能够反映农业磷科学和管理方面的进展。
