This story started when Zach Lybarger, then a senior at North Manchester High School, attended a field day on cover crops at Jamie Scott's farm near Pierceton. He was fascinated by the wide variety of crops that could be planted, and by the idea that these cover crops could produce roots that would run several feet deep into the soil.
Interested in soil conservation, he could see a definite advantage. He also observed displays prepared by Hans Kok of the Indiana Tillage Initiative, in which he grew various cover crops in small plastic boxes to show how many roots various cover crops could produce.
Lybarger became so hooked on the idea that he decided to figure out how to illustrate what these crops could do for the soil. Part of his motivation was to learn if there were differences in how deep roots would go for various cover crops.
With help from Scott and Kok in obtaining seed, he secured 10 plastic tubes each four foot long and filled them with regular soil from his family's farm. Then this past April, he began planting seed- a different cover crop in each one. By early July, his results were nothing short of amazing. He had roots growing to the bottom of the tubes for several crops.
Realize that soil in a field may be more dense than the soil that filled his tubes. Still, his demonstration shows just how many roots and how long of roots that various cover crops can produce. Kok and others say these roots have value in loosening the soil. When these crops decay, they also add organic matter.
The 10 covers that Lybarger tried included subterranean clover, crimson clover, Persian clover, Austrian peas, buckwheat, oats, cereal rye, dikom radish, hairy vetch and annual ryegrass. It's annual ryegrass that has grabbed much of the attention lately as a cover crop that will produce much more growth in roots underground than it does aboveground growth in the spring, helping benefit the soil.
What did he find? By early July, roots were 30 inches down the tube for subterranean clover and 20 inches deep for crimson cover. For whatever reason, his Persian clover struck out germinating and didn't grow. Austrian peas were also rooted to about 20 inches. All of these depths were more than Lybarger expected. Buckwheat roots were also around 30 inches into the tube, and were bright red in color.
Then his interest really perked up. Oats, cereal rye, dikom radish and hairy vetch all produced roots running the entire length of the tube, or 4 feet long. Annual ryegrass had rooted to about 30 inches in depth.
Lybarger realizes that his situation was artificial in that he was able to water his seeds whenever he wanted, and that they were planted at different times than they might be planted on the farm. For example, most cover crops will be seeded from late August through early October. Oats, which doesn't survive the winter, would be expected to die back if planted in late fall.
Nevertheless, his demonstration proves that these covers have the ability to produce roots that run deep, maybe even deeper than previously advertised. The trick is figuring out how to incorporate the right choices into your system, experts say.