Whether you’re planting cover crops to get nitrogen back into the soil or to assist with erosion control, it’s a process that requires patience.
According to Cody Jones, a technical agronomist with Monsanto, a first-time cover crop grower should set their expectations correctly so they don’t set themselves up for disappointment.
“The benefits of cover crops accumulate over time. It’s not something they are going to see a huge benefit from the first year and that they are going to see that same benefit every year,” said Jones, who lives in West Texas and supports the Channel brand across the Southwest. “For erosion control and wind protection, you see that immediately. But if you’re talking about improving soil health — whether that’s nutrients, organic matter, or soil structure — those benefits accumulate over time.”
For instance, some of Jones’ growers have seen a 1 ½ to 2 percent yield increase the first year planting a cover crop. Three years into it, those same growers have seen an 8 to 10 percent yield increase.
Before planting cover crops, Jones said growers also need to consider their primary objective for doing it.
“Is that erosion control? Is it providing nitrogen for a subsequent crop? Is it trying to scavenge residual nitrogen so it doesn’t leach out and get lost?” Jones said. “Or is it alleviating soil compaction? Or is it a forage for winter grazing? Once you define your objectives that will define what you plant and when you plant it.”
Jones said if planting a legume or a grass legume mix to add nitrogen for a subsequent crop, that would need to be planted a little bit earlier — either right at maturity of the previous crop or as soon as you can get in afterwards to get some growth on. If it’s a cereal rye or wheat, that can be planted after you harvest your other crop.
In West Texas, most of Jones’ clients are planting cover crops due to the wind and sandy soils in order to provide protection for the young seedlings coming up in next year’s crops. Most of their choice cover crops for the region are wheat or rye, with some oats. They are planted in the fall and then let go through the winter.
Jones said some of his growers have found success planting solid across the field while others have planted in the middle to save on seed cost and to deal with lack of moisture.
“A lot of our guys strip till and it just leaves kind of a clean little row that they can run their strip till rig down and plant right back into it,” Jones said. “It doesn’t have to be planted solid to protect from the wind as long as there is something out there standing versus bare. Sixty to 80 percent ground cover is still way better than bare dirt.”
Finally, Jones said growers need to consider when and how they are going to terminate the cover crop.
For legumes in the North a winter kill can be used. Tillage is another option, but often not a popular choice to control cover crops. In the South, Jones said almost all growers terminate chemically about two to four weeks prior to planting the next crop.
Growers should also keep in mind when they will need to terminate it and when they are going to plant the next crop into it.
“Legumes, you want to leave up as long as you can to get as much nitrogen as you can. With cereal crops, you don’t want to let it get to the reproductive stage and head out because it will cost to try to kill it,” Jones said. “As far as planting back into a cereal, I like my guys to kill it at least two weeks if not a month before they plan on planting. That way I know it is not getting to big and its completely dead when they plant into it so it’s not using critical moisture that the corn or soybeans might need to germinate and get going.”
Last, but not least … be patient.
“Know that it takes time,” Jones said. “It’s not an instant fix … just like most things we do in agriculture.”