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

Abstract

Base 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 peerreviewed 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. INTRODUCTIONBase cation saturation ratio (BCSR) or "soil balancing" is a soil management philosophy which strives to maintain targeted base cation saturation percentages in soil, typically 60-

Organic Corn Production Practices and Profitability in the Eastern U.S. Corn Belt

“…Future research on the use of conservation tillage in the context of organic farming could provide important insights for adapting current systems and improving the environmental footprint of organic corn production [47][48][49]. Likewise, producers use a wide range of purchased products on their organic corn fields, many of which have received little attention from the scientific community [50] and should be further explored in terms of their agronomic and economic benefits for farmers.…”

Managing soil acidity vs. soil Ca:Mg ratio: What is more important for crop productivity?

“…Given the lack of positive effects of BCSR management on crop yields in published studies (Kopittke & Menzies, 2007;Chaganti et al, 2021), we questioned whether the positive benefits attributed to a higher Ca:Mg ratio by BCSR practitioners could be due to increasing soil pH, rather than increasing Ca saturation levels, both of which typically occur after lime application (Culman et al, 2021). Thus, we hypothesized that optimizing soil pH, not Ca:Mg ratio, would increase grain yields, and that optimizing Ca:Mg ratio without managing soil acidity would have little effect on yields.…”

“…Calcium and Mg are essential nutrients for plant growth (Hirschi, 2004; Shaul, 2002), but their role in soil, particularly their relative influence on soil structure, is not well understood (Chaganti & Culman, 2017; Culman et al., 2021). Calcium plays a role in improving soil aggregation by complexing to organic matter substrates and to the negatively charged surfaces of clay particles (Clough & Skjemstad, 2000; Rowley et al., 2018; Six et al., 2004), playing a putatively important role in soil organic carbon stabilization (Rowley et al., 2018).…”

Soil fertility status and land suitability evaluation for rice crops on former shrimp ponds

“…Nevertheless, recent reports also recorded perceived positive impacts and long-term use of BCSR among many American farmers (Brock et al 2020;Culman et al 2021) as well as its continuing efficacy studies (Souza et al 2016;Bonomelli et al 2019;Chaganti et al 2021). Some researchers and soil scientists designated that the BCSR approach is also essential in terms of lime, gypsum, soil acidity, and cation competition study (Webster 1985;van Biljon et al 2007;Wood & Litterick, 2017;Culman et al 2021). Biswas et al (2019) suggested that (Ca + Mg)/K ratiogoverned the grain yield of rice.…”

“…This concept theorized that the decrease of crops yield response occurs while the soil nutrients concentration is approaching sufficient level (McLean, 1977). Several researchers have reported the BSCR and SLAN study in subtropical soil (Eckert & McLean, 1981;Liebhardt, 1981;Favaretto et al 2008;Brock et al 2020;Culman et al 2021). However, the research conducted in tropical soils, especially in the study area were found scarce (Hikmatullah & Al-Jabri, 2007;Anda, 2012;Assefa et al 2020;Kasno et al 2021).…”