Gypsum is a high calcium (Ca) and sulfur (S) containing mineral used to improve soil fertility and physical characteristics in organic cropping systems. However, evidence regarding short-term improvements in soil properties and increased crop yield is lacking. We conducted replicated experiments on 14 different organic dairy farm fields in five Ohio counties in 2017 and 2018. Our analysis evaluated short-term effects of gypsum application on (a) nutrient concentrations in soils and crop tissues, (b) yield of corn (Zea mays L.) and forage (alfalfa [Medicago sativa L.] or alfalfa-mixed grasses], and (c) and soil health properties. There were no effects on the yield of corn and forage after one or two annual gypsum applications. Still, gypsum consistently increased S concentrations (P < .1) in soil and crop tissues as soon as 5 mo after each application. Gypsum had no measured effects on soil mineralizable carbon (C), penetrometer resistance, or unsaturated hydraulic conductivity in the short term. Soil protein, permanganate oxidizable C, and Mehlich-3 magnesium levels were lower after the second application (P < .1). Our results indicate a short-term effect on some soil and crop nutrients but no additional benefits to soil health or crop yield in the short term when gypsum was applied to organically managed soils.

Continuous declines in atmospheric sulfur (S) deposition along with increased S removal rates with crop harvest has the potential to lead to S deficiency in Ohio field crops. As a result, S fertilization has become more common over the past decade.However, the extent of S deficiency is unknown, as inherent soil properties and management practices influence S availability and uptake. We conducted 96 replicated trials, from 2013 to 2021 to (1) examine the response of corn (Zea mays L.), soybean [Glycine max (L.) Merr], and wheat (Triticum aestivum L.) to S application on a wide range of Ohio soils and differing management practices and (2) determine the ability of Mehlich-3 extractable S in soil, leaf S, and grain S concentrations to predict grain yield response to S fertilizer. Our results showed limited grain yield increases to S fertilization with an overall response rate of 7.3% (4 of 50 corn trials, 3 of 34 soybean trials, and 0 of 12 wheat trials). Sulfur fertilization increased leaf and grain S concentrations by 19.4% and 12% in corn, by 22.2% and 7.7% in soybean, and by 41.7% and 0% in wheat, respectively. These increases in leaf or grain S concentrations were not directly related to yield responses. Diagnostic tools of Mehlich-3 soil S, leaf S, and grain S concentrations failed to predict yield response to S. We conclude that S deficiency is not widespread in Ohio soils and that optimizing grain crop production does not currently require S fertilization. INTRODUCTIONSulfur (S) is essential for numerous plant processes but has not been traditionally applied to agricultural soils in the Midwest (Dick et al., 2008). Historically, relatively large rates of S were supplied from atmospheric deposition in readily available forms for plant absorption (Dick et al., 2008