Controlling Winter Annual Bromes
Cheatgrass, sometimes called downy brome or wild oats, is an annual weedy grass that can be a problem in pastures, particularly in central and western Nebraska.
Cheatgrass often invades thin or overgrazed pastures in fall and early spring. Livestock dislike grazing it after it becomes mature and over time it can take over and create large patches in a pasture.
Research by the University of Nebraska evaluated herbicides for controlling cheatgrass. Products containing rimsulfuron and imazapic can provide good control of cheatgrass from a single application, but control can vary widely from year to year depending on when the application is made, plant maturity and weather patterns. A one-time management operation utilizing grazing, mowing or a non-residual herbicide usually does not have a lasting impact on the cheatgrass in the seedbank. To reduce the seedbank, control needs to be close to 100% and repeated over several years.
Rejuvra™ is a new rangeland herbicide product from Bayer that works differently from existing cheatgrass herbicides. Rejuvra™ has limited activity on emerged plants and only controls seedlings as they germinate, so it is best to apply Rejuvra™ in early fall before seed germination. This herbicide can provide control up to two years post application.
For warm-season grass pastures, you can use glyphosate herbicides after top growth of these grasses has gone dormant due to a hard freeze or two. This can kill emerged annual brome seedlings or other cool-season species without harming the desirable grasses. With any herbicide, always read and follow label directions.
Fall Grazing Balance
After several dry falls in a row, this year may be shaping up a little differently. With recent rains and cooler weather, cool-season pastures like brome, bluegrass and fescue could put on some extra growth. That’s good news — but it also raises the question: do we graze it now or save it for later?
Grazing now can ease feed pressure and provide high-quality forage before crop residues open up. Stockpiling, on the other hand, sets up feed for late fall or winter and cuts down on hay use.
But remember — fall is when grasses rebuild root reserves and set buds for next spring. After repeated drought stress, some pastures could use extra rest. If you’ve been battling weeds, that’s a red flag that recovery time is needed.
If you do graze, rotate quickly and leave at least four inches of stubble on cool-season grasses. Overgrazing now can slow green-up next spring, while stockpiling uses forage later when plants are already dormant.
Fertility also plays a role. While the window for nitrogen is nearly closed, a small application with moisture can still boost growth. Phosphorus and potassium don’t add fall yield, but they support root health, persistence and winter survival.
This fall may offer a rare opportunity for extra grazing. Managing it wisely can fill feed gaps today without sacrificing productivity next year.
Grazing for Interseeding
Pastures and hay meadows provide higher quality feed, are more productive, and require fewer inputs when they have good forage legumes growing in them.
Outside of moisture, nitrogen is often the limiting nutrient in pasture production. While commercial fertilizer may be a quick and easy option, it’s costly. Instead, let’s grow our own nitrogen using legumes.
Do you have a pasture area or hay meadow that is relatively free of weeds and makes up no more than about 15% of your total pasture acres? If so, here is what I want you to do. From now until that grass will grow no more this year, graze that grass hard. Grub it down, then graze it some more.
Now why would I recommend overgrazing? Surely, it will hurt the grass. Well, that's exactly what we want. Next spring, you will interseed legumes like red clover, white clover and alfalfa into that grass to make it more nutritious and productive. We may even consider a winter frost seeding if conditions are right.
The biggest challenge to establishing legumes into a grass sod is competition by that existing grass on new, slow growing legume seedlings. Anything you do to reduce competition and slow down grass growth will help. Overgrazing this fall prior to next spring’s seeding will weaken the grass and slow its spring growth, thus giving new legume seedlings a better chance to get started. Areas that experienced drought this summer may have seen unplanned overgrazing this summer, interseeding may be a way to make some lemonade out of that particular lemon. Of course, all this depends on moisture next spring to work.
While you’re at it, collect some soil samples as well. Then analyze them and apply any needed fertilizer. Legumes especially need good phosphorus and the proper soil pH.
So, add some legumes to your pasture next spring. Graze your grass this fall until virtually nothing is left. Then, keep grazing a couple weeks more just to make sure. Legumes you add next spring will establish better because of it.
