Ben Franklin established the benefits of gypsum on his farms more than 200 years ago. Yet agricultural gypsum application proves an unfamiliar concept for many growers.
Gypsum is a soil amendment and nutrient source. Among its attributes, gypsum improves soil structure which increases water infiltration and reduces ponding, expands the root zone, and decreases erosion and nutrient loss. Gypsum also adds vital nutrients, including sulfate sulfur and calcium.
But the expense and availability of mined gypsum limited its use to high-value specialty crops like peanuts and potatoes, until recently.
Today, GYPSOIL brand gypsum offers low-cost, high-quality synthetic gypsum that is an alternative to the higher priced mined gypsum. As a result, more growers and applicators want to learn how to apply agricultural gypsum as they prepare for post-harvest fieldwork.
“Gypsum is quite different from most other bulk materials that you may have had experience with,” says Ron Chamberlain, GYPSOIL’s chief agronomist and founder. “Gypsum is very fine and requires some learning on how to handle it. But once you figure it out, it’s really not difficult.”
GYPSOIL brand gypsum is calcium sulfate dihydrate (CaSO4 2H2O) and it typically contains 13-16% sulfur and 17-20% calcium. It is produced during the removal of sulfur from the flue gases of coal-fired utilities, and from fermenting corn for food products. GYPSOIL resembles a powder that feels damp to the touch, similar to slightly moistened flour or biscuit baking mix.
Informed applicators avoid common mistakes, Chamberlain says. For example, applicators too often scoop ground debris while loading gypsum, which causes the material to plug and bridge in the spreader. Careful loading eliminates the problem, Chamberlain says. Proper equipment selection and set up is also important to ensure trouble-free application.
Applicator Travis Ulmer touts success with applying gypsum. He operates a custom application business and distributes GYPSOIL from New Haven, IN.
“I’ve had real good luck with the product,” Ulmer says. “It spreads easy for me. I have two pretty good machines that handle it really well.”
Here are tips for effective application of GYPSOIL brand gypsum:
- Choose the right fertilizer, lime or litter spreader.
- Modify spreaders with painted boxes, interior shields or partitions for gypsum application.
- Make adjustments near the spreader gate to improve the distribution pattern.
- Adjust the door height based on the application rate and the spreader’s ground speed.
- Store gypsum undercover if possible.
- Load carefully.
- Allow for small adjustments in equipment and practices when you begin.
- Apply gypsum any time that it is appropriate to be in the field without damaging the soil or the crop.
- Apply gypsum in any tillage system.
- Use soil tests to determine gypsum rates.
- After several applications, growers may benefit from variable-rate application.