Iowa Grower Builds Soil, Stabilizes Organic Matter Losses with Cover Crops

Going to No-till in the late ’70 helped reduce loss of organic matter,” said Iowa grower Steve Berger, “but adding cover crops in the past decade has really made a difference. “The organic matter present in the fence rows is between 5% and 6% but less than 4% in the fields. With cover crops, we have stabilized the losses we continued to see in our soybean rotation.”

Boosting organic matter is important, but Berger says these other things are more easily accomplished and witnessed:

• Better, “mellower”, soil structure
• increased microbial action
• more root channels for corn roots to follow
• the soil’s “bulk density” is down
• infiltration rate of precipitation is up
• soil erosion on his rolling, terraced fields is reduced

Berger has used cereal rye as a cover crop pretty consistently but tried annual ryegrass about five years ago because of its deeper rooting and its ability to soak up and store nitrogen for use during the next crop season. “That’s important, especially in wet years,” he said, “because annual ryegrass will cycle nutrients and keep them from being flushed out of the field through the tiles.”