Meta-Analysis of gypsum effects on crop yields and chemistry of soils, plant tissues, and vadose water at various research sites in the USA

Authors: KOST, DAVID - The Ohio State University; LADWIG, KEN - Electric Power Research Institute (EPRI); CHEN, LIMING - The Ohio State University; DESUTTER, TOM - North Dakota State University; ESPINOZA, LEO - University Of Arkansas; NORTON, DARRELL - Retired ARS Employee; SMEAL, DAN - New Mexico State University; Torbert, Henry - Allen; Watts, Dexter; WOLKOWSKI, RICHARD - University Of Wisconsin; DICK, WARREN - The Ohio State University

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/18/2018
Publication Date: 8/2/2018
Publication URL: https://handle.nal.usda.gov/10113/6563713
Citation: Kost, D., Ladwig, K., Chen, L., Desutter, T., Espinoza, L., Norton, D., Smeal, D., Torbert III, H.A., Watts, D.B., Wolkowski, R.P., Dick, W.A. 2018. Meta-Analysis of gypsum effects on crop yields and chemistry of soils, plant tissues, and vadose water at various research sites in the USA. Journal of Environmental Quality. 47:1284-1292.
DOI: https://doi.org/10.2134/jeq2018.04.0163

Interpretive Summary: Gypsum has a long history as a soil amendment. A common source of gypsum currently available is flue gas desulfurization (FGD) gypsum. Information about the effects of FGD gypsum use on soil, water and plant properties across a wide range of climates and soils is often lacking. A meta-analysis to summarize these effects across a network of 10 field studies at widely separated geographic areas of the United States. Each study used three rates each of mined and flue gas desulfurization (FGD) gypsums plus an untreated control (check) treatment. The meta-analyses focused on response ratios (treatment value/control value) for crop yield or for each measured element. Most response ratios varied only slightly from 1.00. Gypsum had greater effects on statistically changing the response ratios from 1.00 for vadose water than for soil or crop tissue in terms of numbers of elements affected (11 for water, 7 for soil and 8 for crop tissue). Gypsum had no significant effects on crop yields in this short term study, with response ratios of 0.987 for mined gypsum and 1.00 for FGD gypsum.

Technical Abstract: Gypsum has a long history as a soil amendment. A common source of gypsum currently available is flue gas desulfurization (FGD) gypsum. Information about the effects of FGD gypsum use on soil, water and plant properties across a wide range of climates and soils is often lacking. We conducted a meta-analysis to summarize these effects across a network of 10 field studies at widely separated geographic areas of the United States. Each study used three rates each of mined and flue gas desulfurization (FGD) gypsums plus an untreated control (check) treatment. Gypsum rates varied among studies and included a presumed optimal agronomic rate plus one rate that was lesser and one rate that was greater than the optimal. Gypsum was applied once at the beginning of each study and then data were collected for two to three years. The meta-analyses focused on response ratios (treatment value/control value) for crop yield or each measured element. These response ratios were tested for their significance with z values. Elements As, Be, Cd, Co, Fe, Pb, Se, Tl in crop tissue and vadose water were not included in the meta-analyses because concentrations were almost always below detection limits. Most response ratios varied only slightly from 1.00. Gypsum had greater effects on statistically changing the response ratios from 1.00 for vadose water than for soil or crop tissue in terms of numbers of elements affected (11 for water, 7 for soil and 8 for crop tissue). The highest response ratio for soil was 1.57 (Ca), for crop tissue was 1.35 (Sr), and for vadose water was 4.22 (S). The lowest response ratios occurred in crop tissue for Mg (0.89) with FGD gypsum and for Ni (0.92 or 0.93) with both gypsums. Gypsum had no significant effects on crop yields in this short term study, with response ratios of 0.987 for mined gypsum and 1.00 for FGD gypsum.