GypsoilFor veteran no-tiller Cameron Mills, complementing no-till corn and soybeans with cover crops and gypsum creates a winning combination that improves yields. Mills started using cover crops in 2006 and began applying gypsum a few years later.

"We are using all three of these practices - continuous no-till, cover crops and gypsum - as tools to improve soil quality," says Mills, who farms about 3,000 acres of corn and soybeans near Walton in north central Indiana.

"We have seen about a five bushel increase in our beans and are still working on corn yield definition," Mills says. "Our soil health has improved and this will translate into good yields."
Mills says he was first drawn to no-tilling for economic reasons because it requires less equipment and uses tractors with lower horsepower.

Soil quality improvement was another important draw. "By no-tilling, there are more earthworms and our soil biology became more active. It reduced soil erosion and we also got better nutrient placement, too. All of these things came together," Mills says.

Mills learned about cover crops from other no-tillers. He tried 100 acres of cover crops – some to annual ryegrass and some to cereal rye -- the first year. Now, he wants to seed all of his acres with cover crops, if possible.

The success other no-tillers saw with gypsum led Mills to try GYPSOIL™ brand gypsum. GYPSOIL is calcium sulfate dihydrate (CaSO4 ?•2H2O). It is produced during the removal of sulfur from the flue gases of coal-fired utilities, and from fermenting corn for food products. It contains about 13-16 percent sulfate sulfur and 17-20 percent calcium. "After trying gypsum for a year, I jumped into using it with both feet," Mills says.

"You could test things for 10 years, but by then you would lose the benefits of early adoption."

Mills first applied one ton of GYPSOIL per acre on all of his land in 2010. "Since then, I've applied one ton an acre on half of my acres every year," he says.

Mills says that after several years he sees concrete benefits of using gypsum with continuous no-till and cover crops.

"My fields can handle a rainfall event much better now that I'm using cover crops and GYPSOIL with no-till," Mills says. "The fields will hold a rain of 1-2 inches per hour. It will soak in, instead of running off. When a big thunderstorm moves through, the cover crops and the crop residue from no-tilling and the earthworm channels all help protect the soil and take in that hard rain. Instead of the soil being sealed and crusting in the spring when it rains, the water all soaks in nice and easy."

With better water infiltration, the soil holds more water, Mills says.

"The crops can go through drier spells better and that makes all the sense in the world to me," he says. Although the drought of 2012 had a negative impact on his crop yields, Mills says he thinks the soil management practices he uses, including no-tilling, cover crops and gypsum, helped his fields compared to some other nearby fields.

Improved soil structure is especially important during extreme weather conditions such as too little or too much water, says Ron Chamberlain, GYPSOIL's founder and lead agronomist. "When gypsum is used to create a strong, stable soil structure where soil particles are well-aggregated with adequate pore spaces, more rainwater is absorbed into the soils. "Water is sponged down earlier in the heavy rain periods and then remains available to the crop when it needs it," Chamberlain says.

By using gypsum, Mills says his soils do not crust in the spring, the sulfur levels have been increasing in soil tests and the calcium-magnesium ratios have become more balanced. He wants to see a calcium-magnesium ratio of 7:1 or 8:1 and will continue working to achieve that ratio.

Soil tests, Mills says, will dictate his future rates and frequency for gypsum applications. "I may variable-rate apply GYPSOIL," says Mills. "It's going to be a learning curve as I develop more of maintenance program."

Improving Water Infiltration and Yields

Crop consultant Joe Nester, owner of Nester Ag, Bryan, Ohio, works with farmers in western Lake Erie basin, where there are many fields with heavy clay soils that are difficult to plant crops and also poorly drained.

"The No. 1 factor that affects yield in the field is water availability," says Nester. "Yield potential depends on how we minimize water stress and the duration of stress."

If magnesium levels are too high in soils, soil structure disperses and water infiltrates poorly, says Greg Kneubuhler, an independent crop consultant and owner and president of G & K Concepts, Harlan, Ind.

"Recoverability (from rain storms) is huge," Kneubuhler says. "If magnesium levels are too high, then there's poor water infiltration with more soil erosion."

By managing heavy clay soils with gypsum, farmers can improve soil structure and increase the volume of air and water than can enter the soil, he says. This improvement allows roots to breath and develop and the larger root mass captures more water and nutrients, which improves yields.

"It really comes down to the health of the soil," Kneubuhler says.

Indiana grower Mills is convinced the combination of no-till, cover crops and GYPSOIL has led to tangible results on his farm. "Individually, they aren't ‘silver bullets.' But as a system, they improve the soil and its productivity. And using all three together has worked well on my farm. Our soil health is improving. We see that when we do root pit digs."

SIDEBAR: Which soils are best-suited for gypsum applications?

Many conservation-minded growers have turned to gypsum to improve soil physical properties and add nutrients to their soils. But are some soils better suited for gypsum than others?

Dan Towery, an agronomist who owns Ag Conservation Solutions, Lafayette, Ind., looks at the overall impact of continuous no-till, cover crops and gypsum on soil health and crop roots.
"If there is less compaction, and there is a healthier environment, roots have an easier time growing," says Towery, who has worked with no-till for 30 years and with cover crops for about 10 years. "I think this system of continuous no-till, cover crops and gypsum works, but there is still a question, ‘Does using gypsum help more in some soil types over other soil types?'

Ron Chamberlain, founder and chief agronomist for GYPSOIL, has been observing gypsum application for the past 12 years. His experience suggests that with the exception of pure sand or silt, many soil types respond to gypsum applications. However, he says, soils with higher clay content are more likely to have structure issues, especially when other factors are not optimal such as calcium and magnesium levels, tillage practices, manure applications, topography and drainage. "These soils typically show an even greater response to gypsum than lighter, coarser soils," says Chamberlain.

Towery continues, "It's important to look at the system and see if farmers will get positive results across all soil types."

Long-term field research by The Ohio State University (OSU) scientists has identified some of those soils, say Randall Reeder, agricultural engineering emeritus professor at OSU and Dr. Rafiq Islam, a research scientist at OSU.

"Over time, applying gypsum in sandy-loam soil enhances water holding capacity," Islam says. "In clay soil, gypsum makes good soil structure to create macropore spaces and will help the water infiltrate more easily, too. Gypsum contains sulfur, which will improve soybean yields because the sulfur is an important component of enzymes that regulate biological nitrogen fixation from the atmosphere. It is also an important component of amino acids that synthesize proteins."

In 2012, soybean yields in one OSU experiment at Piketon, OH, increased 5-6 bushels per acre in a continuous no-tilled corn-soybeans-wheat rotation with cover crops and gypsum. An earlier OSU study demonstrated an eight percent yield increase in corn with gypsum used to supply sulfur.

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