This piece is drawn from a presentation Jim Gerrish did in 2015 sponsored by the Iowa Beef Center. We’ve embedded the 15:20 video of the presentation where Jim talks about the benefits of “wasting grass.” We’re also summarizing it in two bite size articles to make it easier for all you farmers and ranchers on the go and those of you with slow internet connections. Check out Part 1 here. Part 2 starts at about 7:54 in the video.
In the first part of this video, Jim talked about the benefits of “wasting grass.” What he’s actually talking about is not grazing grass too short and leaving enough residual that there’s a good solar panel protecting the soil, keeping it cooler and holding water in, and the grass can regrow quickly. But what is the right height?
We start by looking at a typical pasture – short grazed pasture and tall bunchy clumps. All that short grazed grass is phase 1. The cattle grazed it early in the season, it tries to grow a bit, and the cattle bite it off again. The tall clumps, Phase 3, might be a different species, or they might be grass that didn’t get grazed early and is now too mature for the cattle to want to eat it. If you look straight down, you’ll see bare ground. What you don’t see in this pasture is phase 2. If you’re hoping for a good solar panel in your pasture, this isn’t how you get it.
What Does a Phase 2 Grass Look Like?
Phase 2 is the objective in Jim’s pasture. Phase 2 will look different depending on the kind of grass in your environment. But it is always a matter of how many leaves the grass has produced. Phase 2 grasses start with 3 leaves and tops out at 5-6 leaves. Let’s look at some examples.
Native Tallgrass Prairie
Here you have switchgrass and bluestem. In the prairie grasses, the leaves are just further apart on the stem. The top side of Phase 2 might be 24″ to 30″ or more. The bottom end is 8-12 inches.
Orchard Grass, Brome, Fescues
The top side of Phase 2 is 14-14 inches with the bottom end at 4 to 5″
Bluegrass and Ryegrass
These fine grasses might never need to get very tall. IF it has ample water, it might never get above 6 or 7 inches and and you can graze it down to two inches or so. Bluegrass and white clover in that zone with a 180 day growing season and plenty of water can provide 6 tons to the acre in forage. The problem is that if you don’t have water you won’t get that kind of production.
NEVER Graze Back Into Phase 1
Whenever you graze back to phase 1 it takes an additional 2 to 3 weeks for the grass to recover to the point that it is effectively capturing solar energy.
You’ve probably seen this picture numerous times. Showing set-stocking on the right with the small roots that result, and no grazing on the far left with it’s huge root system. The two in the middle are simulating rotational grazing. The one on the left is take half leave half. The one on the right is take two-thirds and leave one-third – it’s the kind of management that comes from the fear of wasting grass.
Knocking off roots to grow organic matter is a good thing. But if you graze too short, the plant takes a long time to recover, reducing both your ability to graze, and it’s ability to provide root mass to grow soil organic matter. By managing your grass as Jim Gerrish suggests, you’ll be able to graze numerous times, shedding roots into the soil in pulses, and you’ll grow more grass and more soil organic matter.