Mid to late summer is a good time to check on grassed waterways, if you haven’t already inspected them. Look for eroding channels or areas filled in with sediment.
You may find eroded cuts in waterway centers, or find small gullies along the outer edges or in the crop field where water runs alongside the waterway. Staying on top of small problems can prevent bigger ones.
• Mow grassed waterways after the primary nesting season (July 15).
• Shut off sprayers and use both warm- and cool-season grasses.
• Inspect waterways annually and reshape or reseed as needed.
“Mowing will help keep the grass stand vigorous,” says Mike Kucera, state resource conservationist for the USDA Natural Resources Conservation Service in Nebraska. “If you don’t mow, your grass can become sod-bound and restrict flow in some areas. You’ll get more sediment buildup, and that can redirect water away from the center of the waterway and cause water to flow improperly.”
Because of wildlife concerns, how and when you mow is key. NRCS recommends delaying mowing until primary bird nesting season is over — that’s July 15 over much of the Midwest.
Kucera likes to see mowing a little earlier, though, and has another idea for farmers who want to keep their waterways in top condition and provide wildlife habitat. “If you want to help birds, you should stagger your mowing within season and by year,” advises Kucera. “You could mow half of your waterways each year. Or, you could mow some of them early, in April, before nesting season, and then some in late July.”
Kucera says NRCS encourages haying every other year to remove the vegetation and nutrients, improve the grasses and perform maintenance. Grassed waterways enrolled in the Conservation Reserve Program cannot be hayed, but incidental grazing is allowed with a 25% reduction in CRP payments.
CRP waterways can be mowed, burned or sprayed outside the primary nesting season (May 1 – July 15), though.
Since crop rows often come into waterways at an angle, herbicides for corn and soybeans, especially glyphosate and other burndown herbicides, are a concern. You need to shut off sprayers when you cross the waterway. Planting end rows up and down the hill alongside the waterway isn’t a good way to solve the herbicide problem, since those end rows will channel water alongside the waterway instead of through it. When herbicide drift is a concern, it is best to plant both cool- and warm-season grasses because they have different growth periods and spread the risk.
Betts writes from Johnston, Iowa.
MOW AND BALE AFTER NESTING SEASON: NRCS recommends mowing and baling grassed waterways after primary bird nesting season to keep a waterway functioning and extend its life.
DOWN THE MIDDLE: A well-designed and maintained waterway will direct water flow to its center, without erosion or sedimentation in the channel.
This article published in the July, 2010 edition of INDIANA PRAIRIE FARMER.
All rights reserved. Copyright Farm Progress Cos. 2010.