In recent years, we’re produced a number of No-Till Farmer articles on the benefits of utilizing gypsum to improve plant nutrition and soil structure. Now, new research from Ohio State University indicates gypsum may play a key role in controlling the harmful algal blooms that are a growing concern in Lake Erie, the Chesapeake Bay, the Mississippi River and the Gulf of Mexico.

Blamed on fertilizer and nutrient runoff, dead-zone problems in the Gulf of Mexico can create an oxygen-free zone that in some years can be as large as 8,000 square miles where fish can’t survive.

Coal Plant Byproduct

Warren Dick has found that an abundant byproduct from coal-burning power plants could help control these harmful algal blooms. The soil biochemist has found that appling fluidized gas desulfurization (FGD) gypsum to corn and soybean fields can reduce the amount of soluble phosphorus being washed away from the soil by heavy rains and into waterways.

Dick says the product comes from the air-emission scrubbers at coal-burning power plants. These scrubbers remove sulfur dioxide from the plants’ exhaust emissions, creating a gypsum byproduct that would otherwise be lost to acid rain. The powdery product resembles flour and costs $35 to $50 per ton spread on the field, with a typical application of 1 or 2 tons per acre every second or third year.

Dick says excess soluble phosphorus is the primary cause of the toxic algal blooms that have plagued a number of bodies of water in recent years. The phosphorus…