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1993, p. 262). Sulfur deficiencies of alfalfa have been reported in Ohio, Indiana, Michigan, Wisconsin, and Vir-Sulfur deficiencies in soil are expected to increase due to growth ginia during the 1960s and 1970s (Beaton and Fox, 1971). of high-yielding crop varieties, use of S-free fertilizers, and removal of S from industrial emissions. Flue gas desulfurization (FGD) products, Alfalfa yields were increased by gypsum application in created when coal is burned and SO 2 is removed from the flue gases, sandy loams but not in silt loams in Minnesota (O'Leary may serve as efficient S sources. However, there are few reports on and Rehm, 1989). Waste S applied to alfalfa in the upper their use for the enhancement of crop growth. Agricultural gypsum Midwest at agronomic rates did not affect yields but did and two types of FGD products, that contain either vermiculite or increase the S content of alfalfa plants relative to alfalfa perlite, were applied at 0, 16, and 67 kg S ha Ϫ1 to an agricultural soil grown on untreated soil (Sloan et al., 1999). Alfalfa yields (Wooster silt loam, Typic Fragiudalf). Dry weight of a new planting were not affected by elemental S or gypsum application of alfalfa (Medicago sativa L.) was increased up to 40% by the treatin central Maryland and Prince Edward Island in Canments of FGD products or gypsum compared with the untreated conada (Vough et al., 1986; Gupta and MacLeod, 1984). trol. Gypsum and FGD products were also applied at 0, 8, 16, and 24 kg Sulfur deficiencies not only decrease yield, but also in-S ha Ϫ1 to five established alfalfa stands in different Ohio regions. Mean alfalfa yield was significantly (P Յ 0.05 ) increased by approxi-fluence the feeding value of soybean (Sexton et al., 1997). mately 5.0% in 2001 and 6.0% in 2002 with the S treatments of FGDYields of soybean, in S-deficient fields, were increased products or gypsum compared with the untreated control. Alfalfa yields by almost 30% when supplemental S was added to soil for FGD products and gypsum treatments were similar. A slight posi- (Agrawal and Mishra, 1994). Substantial amounts of farmtive yield response was observed for soybean (Glycine max L.) when land in western Canada have been reported to be S desoils were treated with S-containing materials. Soil and plant analyses ficient, and yields of soybean were significantly increased were made to assess potential adverse environmental impacts and none by S fertilizer treatments (Beaton and Soper, 1986).were observed. Thus, these FGD products can be safely applied to agricul-Sulfur-deficient soils are often low in organic matter, tural soils as S sources and can improve alfalfa yields in S-deficient soils.coarse textured, well drained, and subject to leaching (Waddoups, 2003). The S status of Ohio's soils is not well defined, and S effects on the growth of crops have L. Chen and W.A. Dick, School of Nat. Resour., The Ohio State These components are (i) the SO 2 reaction products, Univ., Wooster, OH 44691; and S. Nelson, Jr., Sorbent Technol. Corp., which are pri...

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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.