M.S. Woods, L.J. Stowell, W.D. Gelertner (2014)
This article introduces the Minimum Levels for Sustainable Nutrition (MLSN) guidelines—a data-driven alternative to conventional soil test sufficiency ranges—for turfgrass nutrition. MLSN is based on over 17,000 soil samples from high-performing turfgrass areas worldwide and aims to identify the minimum soil nutrient levels needed for good turf, rather than targeting arbitrary "optimal" ranges.
The approach helps answer two key questions: whether a fertilizer is needed and how much should be applied. By comparing soil test results (Mehlich-3 extractant) to the MLSN thresholds and estimating nutrient use based on nitrogen application, turf managers can avoid unnecessary fertilization. For example, if potassium is above the MLSN threshold and not expected to fall below it, no additional potassium is needed—regardless of conventional recommendations.
This model-based system improves sustainability by reducing over-application of nutrients, saving costs, and minimizing environmental impact. The article also introduces the “sustainability index,” a metric for tracking how much lower a site’s nutrient levels are compared to traditional guidelines. MLSN guidelines are continuously refined using crowd-sourced soil data, promoting adaptive and site-specific turf management.
