For Release June 26, 2001

AGRI-VIEWS
by Chuck Otte, Geary County Extension Agent

I have had a lot of phone calls and a lot of plants brought into my office this year. Most of the plants had pretty little flowers on them and they all came from pastures or hay meadows. In every case the landowner wanted to know what they were, where’d they come from and how to kill them out of the pasture because they were taking over!

We seem to get in this mind set that if there is a plant in our pastures that is not a grass, then it must be a weed and has to be sprayed. In the tall grass prairie, that simply isn’t the case. One of the things that 15 years of Conservation Reserve Program (CRP) proved to everyone was that, quite simply, a planted stand of all the right warm season grasses could not provide the quality of forage or pasture that a virgin stand could. Why? Because it lacked the forbs.

Forb is the name that range managers use to describe what a lot of us would call wildflowers, or in some cases weeds. Forbs are the non brushy or non woody plants, many of them perennial, that are broadleaved in nature, as compared to the grasses. If you want to get technical, grasses are monocots and forbs are dicots.

Many forbs are legumes. They put nitrogen into the soil through the symbiotic nitrogen fixing bacteria that live on and in their roots. Like all legumes, they are fairly high in protein, often higher than the grasses they are growing with. When small, many forbs are readily grazed by cattle. If the pasture is hayed, a lot of the forbs will be eaten.

So why do there seem to be so many forbs this year? There’s no single factor that will account for it, but more a combination of factors. A decrease in the standing cover last summer and fall allowed for more seedling survival for new plants. Since there was not as much pasture burning this spring, this allowed more of those seedlings to survive. The roots of forbs are often below the roots of the grasses so they are not in direct competition for the same water and nutrients. This allowed the forbs to keep growing longer last year.

The periods of cool wet weather this spring, sprinkled in between warm sunny days, created a perfect environment for many of the forbs to flourish. The impact of last year’s drought had many negative impacts on the grass making them less competitive this spring, thus giving the forbs an advantage. If the pasture has a history of overgrazing, we can see this same effect. If it was overgrazed and went through a drought, consider it the old double whammy.

Are these really weeds and do they need to be sprayed. It depends on what species are being seen. Often, no. But when they do need to be sprayed, we need to also consider what needs to be changed in the management of the pasture to prevent the problem from reoccurring. Weeds aren’t a problem, they are a symptom.

We may need to reduce stocking rates for several years to get the grasses back into dominance. I didn’t say no grazing, but rather grazing at a reduced rate. Moderate grazing pressure is a stimulus to many desirable grasses. We may need to adjust our burning time a little bit later. Simply moving a burning date seven to ten days, one way or the other, can make a big impact on plant composition. But mainly we just need to get out there and start walking through the pastures so that we can learn from the plants that are there!

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