Cover crops, crop rotation, and gypsum, as conservation practices, impact Mehlich-3 extractable plant nutrients and trace metals

Authors: Gonzalez, Javier; DICK, WARREN - The Ohio State University; ISLAM, KNANDAKAR - The Ohio State University; Watts, Dexter; Fausey, Norman; Flanagan, Dennis; BATTE, MARVIN - The Ohio State University; Vantoai, Tara; REEDER, RANDALL - The Ohio State University; SHEDEKAR, VINAYAK - The Ohio State University

Submitted to: International Soil and Water Conservation Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/5/2023
Publication Date: 11/16/2024
Citation: Gonzalez, J.M., Dick, W., Islam, K., Watts, D.B., Fausey, N.R., Flanagan, D.C., Batte, M., Vantoai, T.T., Reeder, R., Shedekar, V. 2024. Cover crops, crop rotation, and gypsum, as conservation practices, impact Mehlich-3 extractable plant nutrients and trace metals. International Soil and Water Conservation Research. https://doi.org/10.1016/j.iswcr.2023.11.001.
DOI: https://doi.org/10.1016/j.iswcr.2023.11.001

Interpretive Summary: Conservation practices are encouraged to support and increase agronomic crop production. Soil tests are often used as a multi-nutrient analysis to determine soil fertility status. A study investigated the influence of gypsum, cover crop, and crop rotation as conservation practices on extractable nutrients from the soil at three midwestern US locations. The soil was collected from 0-6- and 6-12-inches depths five years after implementing the conservation practices. Treatments consisted of (1) with and without cereal rye winter cover, (2) continuous soybean vs. soybean-corn rotation, and (3) annual gypsum application (0, 1, and 2 tons/ac). Differences were observed by site, soil depth, and conservation practice depending on the nutrient evaluated. The most consistent effect was observed for crop rotation across sites. Gypsum only affected the site with the highest clay content, where more calcium and sulfur were retained in soils and magnesium and manganese were lost. Cover crops only affected chemical elements at this high clay site, where different elements were positively or negatively affected. Results suggest that not one practice fits all, and optimum conservation practices must be tailored for the site.

Technical Abstract: Conservation practices are encouraged to improve soil health to sustain agronomic crop production. Mehlich3 is often used as a multi-nutrient extractant to determine soil fertility status. A study investigated the influence of gypsum, cover crop, and crop rotation as conservation practices on Mehlich3 extractable elements from soil at three midwestern US locations. Soil was collected from 0-15 and 15-30 cm depths 5 years after implementing the conservation practices. Treatments consisted of (1) with and without cereal rye (Secale cereale L.) winter cover, (2) continuous soybean [Glycine max (L.) Merr.] vs. soybean-corn (Zea mays L.) rotation, and (3) annual gypsum application (0, 1.1, and 2.2 Mg ha–1). Differences were observed by site, depth, and conservation practice depending on the element evaluated. Minimal interactive effects were observed among treatments. The most consistent effect was observed for crop rotation across sites. Gypsum only affected the site with the greatest clay content, where more Ca and S were retained, and Mg and Mn displaced. Cover crop only affected elements at this high clay site, where different elements were positively or negatively affected. Results suggest that not one practice fits all, and optimum conservation practices need to be tailored for the site.