After harvesting a wheat field six weeks ago, Indiana farmer Paul Russell planted sunflowers, sunnhemp, pearl millet, oilseed radishes, Austrian winter peas, oats, cowpeas, sorghum-sudangrass and Ethiopian cabbage in the field.
It's not a cash crop to be harvested like corn and soybeans, but it's valuable in other ways.
In essence, Russell is growing his own nitrogen fertilizer, aka "green manure;" building organic matter in the soil, suppressing weeds, protecting against wind and water erosion and providing habitat for pollinators and other wildlife before he plants corn in the field next year.
"Those crops will produce nitrogen for the corn crop next year, so maybe that's less nitrogen I have to purchase and apply," Russell, a Delaware County corn, wheat and soybean farmer who also raises sheep, told The Star Press. "It's a natural, organic nitrogen source."
If the field were fenced, the sheep, whose lamb chops he sells at a farmers market, could graze it. He also has the option of baling the field into hay.
The benefits for everyone when farmers grow "cover crops" include less flooding and better water quality when insect killer, weed killer, fertilizer and sediment are not carried off by storm water into rivers, lakes and streams.
The need to maintain and improve farm soil is often overlooked by corn and soybean farmers because of improvements in crop genetics, pesticides and synthetic fertilizer, along with better machinery, according to the agronomy department at Purdue University.
Though Indiana ranks second in the United States behind Texas in most acres (596,061 in 2012) planted to cover crops, the majority of Hoosier farmers still don't do it.
During a recent workshop at cover-crop demonstration plots at the Riggin Farm in Muncie, one skeptical Delaware County grain farmer expressed concern that winter cover crops have the potential to become weeds in the spring.
"The last thing you want in a bean field is sunflowers," the farmer said.
But some cover crops do not overwinter in Indiana, and others can be terminated by herbicides, state agronomist Victor Shelton told farmers from Blackford and Delaware counties.
Deep-rooted sunflowers are effective at "mining" mobile nutrients deep in the soil profile. And their flowers attract bees that are valuable fruit and vegetable pollinators.
"All our little creepy crawly things on the ground absolutely love those (sunflower) seeds," Shelton said. "Mice and voles, also your deer and turkey like that stuff. A very small amount of seed survives the winter. Sunflower seeds also break down with moisture really fast. You shouldn't have too much seed survive unless they till and bury the seed."
No-till farmers grow crops from year to year without disturbing the soil.
"It's like the floor in a woods," Russell said. "You are not disturbing the soils, things naturally decay. You release the nutrients and the plants take it up again and drop their leaves. Mimicking nature is what we're trying to do."
While only small numbers of farmers are planting a mix of cover crops like Russell, "interest is exploding," he said.
During the workshop, Shelton promoted crop diversification, keeping the soil covered as long as possible, soil microorganisms and keeping living roots in the soil as long as possible. In short, managing life below ground, not just above.
"That radish will put a huge tap root on," Russell told The Star Press during a tour of his field. "That sunnhemp is not the (marijuana) hemp we're used to seeing in Colorado making the news. It's a tropical legume for nitrogen. It can grow six feet tall. These plants break up soil compaction."
As the U.S. Department of Agriculture says, Russell's goal is dark, crumbly and porous soil that is home to worms and other organisms that squirm, creep, hop or crawl, soil that smells sweet and earthy, and feels soft and moist.
"This is a long-term commitment, a different layer of management," he said.