Stakeholder perspectives on soil-test-based phosphorus and potassium fertilization in US agriculture

Most public and private phosphorus (P) and potassium (K) fertilizer recommendations are based on soil testing and developed around a critical soil test value (CSTV) to separate responsive and nonresponsive soils. A survey was developed, as part of the Fertilizer Recommendation Support Tool (FRST) project activities, to improve understanding of stakeholder utilization of soil-test-based information for P and K fertilization. The survey consisted of 23 questions and covered topics pertaining to demographics, soil testing goals, the fertilizer decision-making process, fertilizer recommendation philosophy, and FRST use. Respondents were grouped into four categories for analysis: farmers (n = 21), independent crop advisors (n = 84), industry agronomists (n = 104), and public-sector professionals (n = 29). Soil testing was recognized as an important aspect of P and K fertilization decision-making by 91% of respondents; however, less than 8% of respondents in any occupation category reported making P and K fertilization decisions exclusively on soil test information. Yield goal was a key determinant of P and K fertilizer rate decisions for stakeholders, particularly for farmers and industry agronomists. Less than one-half of the farmers, independent crop advisors, and industry agronomist respondents indicated CSTV as being beneficial information to inform rate decisions. The survey results emphasize the importance of strengthening soil-test-based P and K fertilizer recommendations to better reflect stakeholder expectations and align with the key factors influencing on-farm, soil-test-based fertilizer decisions.