Meta‐Analysis of Gypsum Effects on Crop Yields and Chemistry of Soils, Plant Tissues, and Vadose Water at Various Research Sites in the USA

Abstract

Gypsum has a long history as a soil amendment. Information on how flue gas desulfurization (FGD) gypsum affects soil, water, and plant properties across a range of climates and soils is lacking. We conducted a meta‐analysis using data from 10 field sites in the United States (Alabama, Arkansas, Indiana, New Mexico, North Dakota, Ohio, and Wisconsin). Each site used three rates each of mined and FGD gypsums plus an untreated control treatment. Gypsum rates included a presumed optimal agronomic rate plus one rate lower and one rate higher than the optimal. Gypsum was applied once at the beginning of each study, and then data were collected for 2 to 3 yr. The meta‐analyses used response ratios (R) calculated by dividing the treatment value by the control value for crop yield or for each measured element in plant, soil, and vadose water. These R values were tested for their significance with z values. Most R values varied only slightly from 1.00. Gypsum significantly changed more R values 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 R value for soil was 1.57 (Ca) which was similar for both mined and FGD gypsum, for crop tissue was 1.46 (Sr) for mined gypsum, and for vadose water was 4.22 (S) for FGD gypsum. The large increase in Ca and S is often a desired response to gypsum application. Lowest R values occurred in crop tissue for Mg (0.89) with FGD gypsum and for Ni (0.92 or 0.93) with both gypsums. Although some sites showed crop yield responses to gypsum, the overall mean R values for mined gypsum (0.987) and for FGD gypsum (1.00) were not significantly different from 1.00 in this short‐term study. Core Ideas Meta‐analysis was used to evaluate gypsum treatments at 10 sites within the United States. Response ratios were calculated for crop yields and chemistries of soil, plants, and water. Crop yields showed both positive and negative results to gypsum treatments. Most R values for elements varied only slightly from 1.0, meaning no treatment effect. Concentrations of elements in samples were below levels of environmental concern.

Managing Phosphorus Loss from Agroecosystems of the Midwestern United States: A Review

“…Fertilizer amendments such as lime, gypsum, alum, steel furnace slag, and ferrous sulfate biochar, as well as products like Avail (Specialty Fertilizer Products, Leawood, KS) and P 2 O 5 -Max (P-Max, Rosen's Inc., Fairmont, Minnesota, USA) have been used for managing the environmental loss of P or for increasing efficiency of applied P fertilizer [44][45][46][47][48][49][50]. Gypsum and lime are among the most studied amendments added to the soil for managing P (Table 3).…”

“…Gypsum and lime are among the most studied amendments added to the soil for managing P (Table 3). Gypsum generally contains around 23.3% Ca and 18.6% S. Application of gypsum increases Ca levels in the soil solution and reduces soluble P loading from soil to surface waters by absorbing available P in soil solution with the Ca in gypsum [49,[51][52][53]. Greenhouse and controlled environment experiments have reported a reduction of P loss by liming depended on initial STP status.…”

Soybean yield response to gypsum soil amendment, cover crop, and rotation

“…Gypsum (CaSO 4 ∙2H 2 O) is one of the oldest soil amendments and is an excellent source of calcium and sulfur, both of which are essential crop nutrients. Legumes such as soybean are likely to respond to sulfur applications (Kost et al., 2018; Presley, He, & Tomlinson, 2018). Gypsum is available as an underutilized by‐product of the flue gas desulfurization (FGD) scrubbing process required in coal burning electric power generation facilities.…”

Investigating the Effect of Gypsum Powder on Chemical Constituents of Soil and Selected Crops, Adigudem, Tigray, Ethiopia

“…Similar is true for the anions, NO3, PO4 and SO4 (Fig 4C). The soil blend of both crops is found to have more Mg, Mo, Cd, NO3 and PO4 content than the gypsum powder (Kost et al, 2018). Matula and Pechová (2007) pointed out that the insignificant variation in the main cation nutrients (Na, K, Ca, Mg and Fe) can be assumed that the impact of the gypsum treatment on their uptake was mainly influenced by the establishment of equilibrium between the sorption complex of soils and the liquid phase of soils after a radical supply of calcium to soils through the gypsum dose.…”