Continuing concerns with soil conservation, weed control and environmental impact created by herbicides were addressed by Tim Reinbott, MU Bradford’s research farm superintendent, with his talk on Cover Crop Management. Addressing the audience of this year’s Barton County Soils and Crops Conference in Lamar, Mo., Reinbott gave an overview of cover crops, explained some of the good points in implementing cover crops while touching areas to approach with caution. “I wanted also to show them that what I’ve learned with the best methods and what I’ve messed up on as well if they want to experiment with them,” he said.
A hundred years of tilling the land accounts for an accumulated loss of approximately one foot of topsoil through erosion. However that is not the worst of it said Reinbott, organic matter that aids in nutrient cycling, retaining and filtering water and maintaining a beneficial soil structure has become a casualty. “Missouri farmers are still paying for the problems created in improper tillage done as much as over 100 years ago,” said Reinbott in his opening comments.
“I can remember as a kid in the spring when you tilled the soil it had a special aroma to it,” explained Reinbott, “I haven’t smelled that lately in the last 20 or 25 years, because we’ve kept tilling the soil we’ve lost a lot of those good qualities it once had like soil microorganisms. We can recover some of that quality through the use of cover crops.”
An acre of soil has about 1,200 pounds of soil microbes which is about the size of a cow. “If you think of feeding the soil like feeding that ‘cow’ for a profit we want to feed that ‘cow’ all year long,” noted Reinbott. How does one fatten up that ‘cow’ without barraging the soil with chemicals and preventing losses from erosion?
The clue lies in the past with Missouri’s native prairies that contained a tremendous amount of biological activity going on in the soil simply because there was something always growing. That activity leads to maintaining active carbon which is often overlooked in the big picture. “Even though it’s winter, plants are actually growing a little bit, there’s compounds released by the roots, there’s turn over and it really feeds those microorganisms,” he explained, “We’ve really gotten away from that in the last 40 years.”
There are many cover crop options to eliminate or at least minimize the need to till while feeding the soil and livestock. Studies by the University of Ohio have shown by using tillage radish as a cover crop soil compaction decreases by 40 percent or more. MU’s College of Agriculture, Food and Natural Resources has also proven by implementing cereal rye as well aids to loosen soil. Loose soil means significant increases in root growth and density, while paving the way for higher water infiltration levels.
Replenishing soil with nutrients for crops while rebuilding a healthy level of organic matter producers can have choices within legumes and non-legumes as cover crops. Reinbott touched on three popular legumes: crimson clover, Australian winter pea and hairy vetch. Reinbott does caution the use of hairy vetch as it can easily become a two-edged sword. “Some wheat producers have used hairy vetch as their solution only to find that it may crop up at harvest time,” he explained, “If that should happen you could end up losing money as hairy vetch seeds can become harvested with the wheat.”
In the non-legumes cover crop varieties, Reinbott continued to demonstrate potential benefits from using cereal rye, oats and triticale, a wheat and cereal rye hybrid. He noted that cereal rye provides excellent benefits with return on investment (ROI), being winter hardy, suppressing weeds and also plays nice with legumes. He did stress it is important to avoid using ryegrass because of its inherent problematic traits. Reinbott warned, “Ryegrass can become a weed issue overnight and since it is resistant to the best herbicides it is tough to get rid of.”
Like baseball no one hits a grand slam their first time on base unless they are really lucky and it is the same with cover crops. The first step toward a successful season is to understand that cover crops need to be managed like any other primary crop said Reinbott. He added, “You really want to think about what you want to use and why you want to use it.
“Also you need to think about how you are going to get rid of it, because you have to kill it one way or the other. Whether it is from winter kill or coming back using herbicides, are you going to mow it, and you have to think of when you want to do this. You have to pick the cover crop to fit what you want.”
Reinbott summarized, “What I like about this is it fits modern, conventional agriculture, or if folks want to be more sustainable it will work all the way to organic methods. It’s really a long-term investment. Yes, we get some short term in the first year to three years, but the long term it even gets better.”
