The prevalence and practice of soil balancing among organic corn farmers

Abstract

The scientific community and most mainstream agriculturalists typically design fertilizer recommendations to provide a ‘sufficient level of available nutrients’ to meet the annual N, P and K requirements of common field crops. Soil balancing is another approach to managing soil fertility that focuses on the levels of Ca, Mg and K to achieve a desired base cation saturation ratio (BCSR). Soil balancing is believed to be practiced frequently by organic and other alternative farmers but is viewed skeptically by conventional agricultural scientists due to a lack of support for the idea in the published scientific literature. This study represents a pioneering effort to collect systematic data on the extent of soil balancing, how it is practiced and the types of outcomes reported by organic farmers. Our survey of over 850 farmers who grow certified organic corn in Indiana, Michigan, Ohio and Pennsylvania found that over half report using a soil-balancing approach based on BCSR. Their practice of soil balancing frequently includes more than management of base cations, but also uses a wide range of soil amendment products (such as purchased organic NPK fertilizers, micronutrients, microbial stimulants and soil inoculants) other than those applied specifically for cation balance. Farms that rely on vegetable and dairy production for most of their income, and Amish farmers who rely on horses for fieldwork, were more likely to report using a soil-balancing program. Self-described soil balancers perceived positive agronomic outcomes from the use of a BCSR program, including improvements in soil physical and biological properties and improved crop health and quality. Although farmers in our study report extensive use and positive perceived outcomes from soil-balancing methods, the scientific research literature has been unable to reproduce evidence that manipulating soil base cation levels has any systematic effect on crop yield. Future research could consider the interacting effects of BCSR with other field management practices to more closely approximate the actual practices of farmers.

Which management practices influence soil health in Midwest organic corn systems?

“…Interestingly, subscription to BCSR had no influence on Ca/Mg ratios measured in the soils that were submitted for this study. However, two important caveats need to be considered, first, we do not have a strong sense of how long these farmers have been subscribing to BCSR and actively working to change Ca/Mg ratios Brock, Jackson-Smith, Kumarappan, et al, 2021). Second, soils are highly buffered and altering Ca/Mg ratios can require time and heavy amendment application rates (see Chaganti et al, 2021), even when farmers are actively applying high-Ca limestone and gypsum.…”

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

“…While previous scientific research tends to frame BCSR ratios as a competing universal theory to the predominant traditional SLAN approach, this portrayal paints a false dichotomy that does not reflect the lived complexities around the practice. Recent work by and Brock, Jackson-Smith, Kumarappan, et al (2021) based on interviewing BCSR practitioners, reported a disconnect between the science and practice of BCSR. Several important themes emerged from this work including, (a) most BCSR practitioners in organic systems view BCSR not as a central tenet to soil management that is at odds with SLAN, but as one of many practices to manage soil fertility and build soil health, (b) practitioners describe multifaceted benefits to BCSR with a particular emphasis on positive changes in physical structure, and (c) BCSR management approaches can vary by soil type as most practitioners recognize the limitations of BCSR on sandier soils with low cation exchange capacity (CEC).…”

“…The BCSR concept is widely practiced by farmers in the United States, particularly in the organic farming community. In a recent survey of all organic corn farmers in Indiana, Michigan, Ohio, and Pennsylvania, more than half of the respondents (859, 57.4% response rate) described using a BCSR approach (Brock, Jackson‐Smith, Kumarappan, et al., 2021). However, BCSR concepts are not limited to organic farmers.…”

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).…”

“…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).…”