Gypsum, used as a soil amendment to supply soluble calcium and sulfate sulfur, helps soils absorb more water during rainfall, according to USDA ARS research studies. That means more water goes into the soil reserves to be tapped by crops when rains are scarce later in the season.
“The key to getting through drought is to capture all the water you can when you do get rain,” says Allen Torbert, research leader at the USDA-ARS National Soil Dynamics Lab at Auburn, Ala. “Better soil structure allows all the positive benefits of soil-water relations to occur and gypsum helps to create and support good soil structure properties.”
In addition to improving moisture utilization, gypsum helps to keep phosphorus and other nutrients from leaving farm fields. “Using gypsum as a soil amendment is the most economical way to cut the non-point runoff-pollution of phosphorus,” says retired soil scientist Darrell Norton who conducted decades of gypsum research while at the USDA-ARS National Soil Erosion Laboratory at Purdue University.
A testament to its positive contribution to soil and water quality, gypsum application to agricultural fields was recently added to Ohio’s conservation practice standards issued by the Natural Resources Conservation Service (NRCS), notes Warren Dick, professor, Environmental and Natural Resources, The Ohio State University (OSU), Wooster, Ohio.
Dick is the lead researcher for a number of research projects studying gypsum’s impact on soil and water quality, as well as crop productivity. Gypsum has been shown to boost corn yield by as much as eight percent1 and alfalfa yield by as much as 18 percent2 in OSU research.
Dick, Torbert and Norton, along with several other gypsum researchers, industry experts and growers and consultants experienced using gypsum, will be featured speakers at the Midwest Soil Improvement Symposium: Research and Practical Insights into Using Gypsum to be held March 7 at Ada, Ohio. David Montgomery, Ph.D., professor of geomorphology in the Department of Earth & Space Sciences at the University of Washington, and award-winning author of “Dirt: The Erosion of Civilizations,” will present the keynote. Sponsors for the program are Gypsoil, OSU and the Conservation Technology Information Center.
Gypsum, or calcium sulfate dihydrate, has been used for centuries, and was promoted by Benjamin Franklin and George Washington. Colonial crop growers observed fields that were green and lush when mined gypsum or “land plaster” was applied. The cost of mining and shipping gypsum to crop producers, however, caused agricultural use of gypsum to dwindle over time except for on high value crops like potatoes, tomatoes and peanuts.
But thanks to the 1990 Clean Air Amendments, there is a new supply of high quality and lower cost synthetic gypsum available called flue gas desulfurization gypsum or FGD gypsum. FGD gypsum is produced as a co-product in wet scrubbing systems used to clean emissions at certain coal-fired utilities. Gypsum is also a co-product from some food-grade manufacturing processes.
FGD gypsum contains 20 percent soluble calcium or about 400 lbs./ton and 16 percent sulfur (in the sulfate form) or about 320 lbs./ton, explains Ron Chamberlain, director of gypsum programs for Chicago-based Beneficial Reuse Management, which markets Gypsoil brand gypsum. Chamberlain will discuss gypsum spreader set-up and application tips at the March 7 program.
“Gypsum is a fine dry material that many growers and applicators are unfamiliar with handling so a little instruction is often needed,” says Chamberlain. “For best results, gypsum can be applied using a fertilizer or litter spreader designed for bulk materials with just a minimum set-up.”
Gypsum offers a host of benefits to improve agricultural productivity and soil and water quality. For more information, plan to attend the March 7 event. Learn more at http://www.gypsoil.com/.