Getting a Kick Out of Cover Crops

Keeping soil under cover offers perks for soil, water and nutrient conservation

It takes a lot to please soybean farmer Tim Smith, but the results of planting cover crops, of all things, did exactly that.

Smith, a soybean and corn farmer from Eagle Grove, Iowa, started a program last year to plant cereal rye in one of his fields. In the spring, the dead rye plants stored about 30 pounds of nitrogen per acre, he says.

“Thirty pounds of nitrogen in the field from cover crop is pretty exciting to me, and I don’t get excited about much,” Smith recently told a group of food company representatives as they toured his farm.

Eagle Grove, Iowa, soybean farmer Tim Smith talks about how he hopes cover crops gain adoption by other farmers around him to demonstrate how U.S. farmers consistently work to improve their already stellar sustainability performance.

 

The soy checkoff organized the educational program to show how various practices used by U.S. farmers can improve on-farm sustainability performance. The group learned about a variety of practices on farm tours in Iowa, Illinois and Nebraska. The food industry continues to be the biggest user of U.S. soy oil.

Cover crops serve several purposes, Smith says. First, the plants’ roots dig deep, helping break up the soil. They also prevent erosion and increase the amount of organic matter in the soil. But most exciting for Smith, cover crops keep nutrients in his farm fields and out of the water that runs through his drainage tiles and eventually into nearby streams and rivers.

Smith says his combination of strip tillage and planting cover crops makes it easier for soybean and corn plants to establish strong roots.

“The soil is nice and crumbly,” he says. “Cover crops help break up the soil, and earthworms feed on the plant residue and help break it up even more. I saw a YouTube video where a farmer put smoke through his tile and the soil was so porous, the smoke came up through the ground. It was kind of eerie, but it showed the porosity in the soil.”

Smith participates in the Mississippi River Basin Initiative, a U.S. Department of Agriculture Natural Resources Conservation Service program in which farmers in various Mississippi River watersheds implement various practices to reduce nutrient runoff.

Next, Smith will hook up a bioreactor to his tile just before it drains into nearby Eagle Creek. As water flows through the bioreactor, microorganisms remove nitrates from the water, break them down and release them into the atmosphere as harmless gases.