Mike Plumer, an agronomist with the University of Illinois began to recommend annual ryegrass over a decade ago, when he discovered its value as a nitrogen-scavenging cover crop.
“When a soybean plant dies, it immediately starts to degrade. If you get any rainfall on the residue or through the nodules, it’s going to leach nitrogen quickly.”
The rule of thumb about nitrogen has been: Corn crops planted into soybean fields the year after will get a pound of nitrogen for every bushel of soybeans harvested. Plumer says that isn’t the case in southern Illinois or southern Indiana.
“In southern Illinois, our experience has been that we typically get zero nitrogen the following year out of the beans mainly because of warm weather, any rainfall or anything else that’s going to start leaching nitrogen immediately through the profile. We’re going to lose it all by next spring.”
He said that tile lines will often reveal large flushes of nitrates in the late fall after rainfall and again in the spring after the thaw.
“That’s why I got involved looking at ryegrass because when I studied the different cover crops, it has the greatest affinity to hold the most nitrogen. A ryegrass plant can hold up to 800 pounds of nitrogen and still only be 12 inches tall.”
(Information in this article also appeared in No-Till Farmer magazine)
Tags: annual ryegrass as a cover crop, erosion control, Mike Plumer, nitrate leaching, nitrogen scavenging, nitrogen-friendly cover crop help reduce the cost for fertilizer., No-Till, No-Till farming, organic matter, sequesters available nitrogen
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