While farmers have used gypsum (calcium sulfate dihydrate) for centuries, it has received renewed attention in recent years. This resurgence is due in large part to ongoing research and practical insights from leading experts that highlight the many benefits of gypsum.

1. Source of calcium and sulfur for plant nutrition. 

2. Improves acid soils and treats aluminum toxicity. 

5. Helps reduce runoff and erosion. 

The latest information on gypsum has been covered in detail at past Midwest Soil Improvement Symposiums. The event — which has been held in conjunction with The Ohio State University’s Conservation Tillage and Technology Conference — typically includes presentations from industry representatives, scientists, consultants, and growers on the use of gypsum to improve soil structure, reduce nutrient runoff, and more.

Here are five key (and overlapping) benefits of gypsum highlighted at past symposiums:

1. Source of calcium and sulfur for plant nutrition. “Plants are becoming more deficient for sulfur and the soil is not supplying enough it,” said Warren Dick, soil scientist and Professor Emeritus, School of Environment and Natural Resources, The Ohio State University. “Gypsum is an excellent source of sulfur for plant nutrition and improving crop yield.”

Meanwhile, calcium is essential for most nutrients to be absorbed by plants roots. “Without adequate calcium, uptake mechanisms would fail,” Dick said. “Calcium helps stimulate root growth.”

2. Improves acid soils and treats aluminum toxicity. One of gypsum’s main advantages is its ability to reduce aluminum toxicity, which often accompanies soil acidity, particularly in subsoils. Gypsum can improve some acid soils even beyond what lime can do for them, which makes it possible to have deeper rooting with resulting benefits to the crops, Dick said. “Surface-applied gypsum leaches down to to the subsoil and results in increased root growth,” he said.

3. Improves soil structure. Flocculation, or aggregation, is needed to give favorable soil structure for root growth and air and water movement, said Jerry Bigham, Professor Emeritus, School of Environment and Natural Resources, The Ohio State University. “Clay dispersion and collapse of structure at the soil-air interface is a major contributor to crust formation,” he said. “Gypsum has been used for many years to improve aggregation and inhibit or overcome dispersion in sodic soils.”

Soluble calcium enhances soil aggregation and porosity to improve water infiltration (see below). “It’s important to manage the calcium status of the soil,” he said. “I would argue it’s every bit as important as managing NPK.”

In soils having unfavorable calcium-magnesium ratios, gypsum can create a more favorable ratio, Bigham added. “Addition of soluble calcium can overcome the dispersion effects of magnesium or sodium ions and help promote flocculation and structure development in dispersed soils,” he said.

“Agricultural soils have been degraded by centuries of farming practices that disturb soils’ physical properties and create imbalances in soil chemistry resulting in compromised soil biology,” adds Ron Chamberlain, an agronomist with GYPSOIL. “As a result, many soils are no longer able to provide enough natural nutrition and adequate root environment for profitable crop growth. By restoring soil physical properties, gypsum facilitates the natural restoration of soil microbiological complexes which in turn improve soil structure and bring balance to soil chemistry.”

4. Improves water infiltration. Gypsum also improves the ability of soil to drain and not become waterlogged due to a combination of high sodium, swelling clay and excess water, Dick said. “When we apply gypsum to soil it allows water to move into the soil and allow the crop to grow well,” he said.

Increased water-use efficiency of crops is extremely important during a drought, added Allen Torbert, research leader at the USDA-ARS National Soil Dynamics Lab, Auburn, AL. “The key to helping crops survive a drought is to capture all the water you can when it does rain,” he said. “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.”

5. Helps reduce runoff and erosion. Agriculture is considered to be one of the major contributors to water quality, with phosphorus runoff the biggest concern. Experts explained how gypsum helps to keep phosphorus and other nutrients from leaving farm fields. “Gypsum should be considered as a Best Management Practice for reducing soluble P losses,” said Torbert, who showed studies on how gypsum interacts with phosphorus.

Darrell Norton, retired soil scientist at the USDA-ARS National Soil Erosion Research Laboratory at Purdue University, added: “Using gypsum as a soil amendment is the most economical way to cut the non-point run-off pollution of phosphorus.”

Editor’s note: This article originally published in April 2013.

Matt Hopkins is Senior Online Editor for the Agribusiness Group at Meister Media Worldwide (MMW), including such brands as CropLife, CropLife IRON, AgriBusiness Global, PrecisionAg, and Cotton Grower. He is responsible for managing an array of online products, including newsletters, websites, video, and social media. Hopkins originally joined MMW in 1994 as an editor for Greenhouse Grower magazine before transitioning to Business Manager of its MeisterPro division. He has a Communications Degree from Cleveland State University. See all author stories here.

Where is the research to support these comments?

The symposium speakers included spporting data in their presentations. You can find videos of all the presentations given at the 2013 symposium by going to the GYPSOIL website at this link:http://www.gypsoil.com/improving-your-soil/midwest/midwest-soil-improvement-symposium/2013-symposium

Also, GYPSOIL maintains a large Research Library of peer-reviewed research papers; proceedings, bulletins and research reports; slide sets and popular press articles at the link below. It is easy to search the Library for specific topics pertaining to gypsum such as water infiltration, aluminum toxicity, sulfur, erosion, etc. You can also search by state and researcher name. Find the Library at this link: http://www.gypsoil.com/research-library?&filterCrop=&filterFocus=&filterState=&filterCategory=&filterKeyword=&pagenum=6

I used gypsum for my paddy garden on sowing, i hope it'll helps in Good

Could I mix the Gypsum into the NPK mixtures? Is Gypsum suitable to use in Tropica soil, for Palm oil Tree?

any required amount of gypsum to be applied (maybe on a hectare basis)? if soil analysis is not available?

You should include its role in curing alkaline and sodic soil

Dear sir or madam. It is nice to know gypsum use as agricultural input What is the prosses? If we produce it who is buying? Regards.

Could I mix gypsum in C4 S1 water?

Hi ,Can use the gypsum in the lower ph level, example-ph.3,ph-4….

Can we use gypsum in organic farming?

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Gypsum is definitely suitable for Tropica Soil. Contact [email protected] for more details.

The Gypsum application amount varies with the requirements of the soil and somewhat with the crops being raised. Since Gypsum is a Soil Amendment as well as an excellent source of Calcium and Sulfur, your existing soil structure will need to be known. That said, within certain geographies, we can estimate the application volume based on the soil on the area. Feel free to contact me for more information.

Generally, Gypsum is pH neutral. However, the amending qualities of this amazing mineral can change soil pH by it’s impact on other forces that impact pH such as Aluminum toxicity.

Non-synthetic Gypsum (Calcium Sulfate Dihydrate) can and is used in organic farming. EcoGEM (www.eco-gem.com) has products certified for organic use by OMRI (Organic Minerals Review Institute) and provides high quality product to organic farmers.

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Can Gypsum be applied to fields that already have crops planted in them?

I have a small farm and we just had to remove old drywall (but it was put in around 1989). I would like to put the scraps on the pasture where the soil is acidic. I don’t see any signs of it being the toxic drywall that china sent. So would it be safe to put on the pasture? The cattle are fenced out of that field.

we farm in Zambia and our irrigation water comes from dolomitic limestone. Prior to applying gypsum several years ago in quantities up to 1.5 t per ha our soils were sticky and hard to get decent tilths. now, we apply between 250 and 500 kg per ha maintenance applications per crop , both prior to planting or over the top and watered in if we didn’t have material on time. we have healthier crops, nicer soils and generally major improvements.

I have worked with gypsum on reclaiming sodic soils and saline-sodic soils for 26 years. I have photos and data from a 5 year trial. If sodium is the issue, it works wonders. However, it does not work for saline soils (EC > 4 mmhos/cm with SAR < 12 or ESP <15) as it will increase EC and make the situation worse. I also worked with it to offset the short-term (<10 years) application of high SAR water for irrigation. I do not follow how it works with acid soils. If you want to contact me for photos or more info, email at [email protected] .

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