Base cation saturation ratios vs. sufficiency level of nutrients: A false dichotomy in practice

Abstract

AbstractBase cation saturation ratio (BCSR) or “soil balancing” is a soil management philosophy which strives to maintain targeted base cation saturation percentages in soil. Despite lack of Land Grant University (LGU) endorsement for decades, BCSR is widely practiced by many farmers in the United States, particularly in the organic farming community. Here, we explore BCSR persistence and present a framework around BCSR that reflects how it is conceived and practiced on working farms, with a key premise that BCSR practitioners typically use both LGU‐endorsed sufficiency level of available nutrients (SLAN) and BCSR in a hybrid approach. Drawing on (a) a survey of LGU soil fertility scientists’ perspectives on BCSR, (b) decades of published literature on impacts of lime and gypsum application, (c) soil test data from organic corn fields in a four‐state region of the Midwest, and (d) a large state‐wide soil test dataset from Ohio, we examined and tested five unique hypotheses about BCSR. We provide evidence to support the following statements: (a) published peer‐reviewed literature on BCSR is limited and dated, (b) there is widespread agreement among soil fertility scientists that BCSR is not a legitimate practice of soil management, (c) studies of lime and gypsum application on soils can lend insight into the efficacy of BCSR, and (d) in many soils, managing soil acidity will also balance soils in BCSR ideal saturation percentages. Collectively, we summarize key findings from our interdisciplinary effort to provide an updated overview and a more nuanced perspective of BCSR in practice.