During the fall we’re accustomed to seeing Iowa colored primarily in tans and browns, as harvested fields of corn and soybeans settle in for the long winter. But over the past few years an eye-catching new color has been popping up in fields all over the state: the bright green of emerging cover crops.

That’s been very clear from my drives around the state this fall. And, thanks to the widespread rains the past couple of weeks, we’re likely to see even more green fields this month before the snows start to fly.

Farmers typically plant cover crops in fall, either just before corn and soybeans are ready to harvest, or just after the combine rolls through. The cover crops protect fields against erosion, improve soil health and are an important tool for improving water quality. Research from Iowa State University shows planting a rye cover crop helps reduce nitrogen losses from fields by 31% and phosphorus losses by 29%.

Most of the bright green we’re seeing this fall is rye, by far the most popular cover crop species on Iowa farms. It’s got a lot going for it. Rye germinates quickly in the fall and overwinters, providing soil and water quality benefits in the late winter and early spring before next year’s corn or soybeans are planted. Indeed, agronomists tell me that it’s in the spring when rye cover crops really shine, holding soil in place, scavenging nutrients to keep them out of streams and even giving cattle something to graze on before the summer pastures green up.

It’s not surprising that we’re seeing more green acres on our drives around Iowa this fall. Surveys on Iowa cover crop acreage are running a little behind because of the pandemic, but momentum was clear in the most recent survey by Iowa Nutrient Research and Education Council (INREC). It pegged cover crop acres at just under 2.2 million as of 2019, a gain of 36% from acreage in 2017 and light years ahead of the only 10,000 or so acres planted before the adoption of the Iowa Nutrient Reduction Strategy in 2013.

Cover crops are the most visible signal that Iowa farmers are taking on the challenge of improving water quality. But collaboration and the adoption of other, less visible, water quality practices are also booming around Iowa. The Iowa Department of Agriculture and Land Stewardship (IDALS), with support from Farm Bureau, is accelerating its efforts to help farmers build wetlands in key watersheds. The state ag agency says:

  • Farmers around Iowa are planning and in the process of building more than 40 wetlands valued at nearly $12 million.
  • Farmers completed 56 saturated buffers and bioreactors projects last year. Those structures are up and running, filtering out nitrates and other nutrients to keep them out streams, rivers and lakes.
  • Farmers, working with IDALS and others, are designing and developing 125 additional bioreactors/saturated buffers.

It’s all starting to add up; Iowa State University researchers show that phosphorus is down by 22% compared to the federal baseline period of 1980 to 1996. And now that proven model is being applied to impact nitrates.

So, it’s not just an added fall color we’re seeing in the countryside, it’s really a whole new attitude.

By Dirck Steimel. Dirck is News Services Manager for the Iowa Farm Bureau Federation and editor of the Iowa Farm Bureau Spokesman.