One of the most popular choices in the rebirth of cover crops is annual ryegrass. With strong support from seed salesmen and their growers, Indiana farmers have given it a look, and most like what they see. It helps capture nitrogen, but it's also amongst the deep-rooted of the cover crops tried so far. That helps loosen soils, especially in areas with Miami or similar tight subsoils.
There is just one major problem with annual ryegrass, assuming you get it started well in the fall. Horror stories about killing annual ryegrass prevent some from trying it!
"It's typically still cool when you want to kill it, and glyphosate doesn't work as well in cool weather," Mike Plumer observes. Plumer is a farmer himself who has experimented with cover crops for decades. He also did cover crop trials before he retired from Extension at the University of Illinois. Last December, he brought his knowledge to a cover crop field day at Sullivan.
Once plants shut down and don't translocate materials to the roots, glyphosate won't be effective.
"Spray glyphosate on annual ryegrass on a warm, sunny day," he says. "It takes about 4 to 5 hours for glyphosate to translocate to the roots. In addition, ryegrass shuts down translocation about one to two hours before sunset.
"Ideally, you need four hours for the process to work. If you spray on a sunny day about 8:30 a.m. to 9 a.m., you should be successful. If you can quit spraying by 1 p.m., it's ideal."
Additionally, Plumer recommends using the full labeled rate plus and AMS adjuvant. One key is to not apply it with atrazine or Callisto. Those products stop translocation, he notes. Your choice of acceptable products include glyphosate, Balance, Balance Plus, Prowl, 2,4-D and Princep, he adds.
"It's the deepest rooted cover crop, which can make it an advantage on glacial till soils," Plumer concludes. "You just have to manage burning it down correctly in the spring."
Learn more from Plumer about cover crops in the April issue of Indiana Prairie Farmer.