Sandy Johnson, livestock specialist
In years with ample rainfall, there may be a tendency to take grass production for granted. If there are so many acres, we expect it to produce so much grass and run so many head of cattle. Putting up hay or even mowing the lawn (non-irrigated) can give us a good indication of forage growth conditions in general. When dry conditions prevail, the normal grazing plan must be changed; and it can be hard for producers to make timely changes for several reasons. Enacting a “plan B” is generally expensive, time consuming, and otherwise unappealing. Some objective measure of grass production would likely help producers make more timely decisions.
Forage use must be measured so it can be managed. Basic yearly records to keep on each pasture include: date of turnout, number of head, average weight, same three points at the time of removal, and rainfall. The other record needed is some measure of utilization at the end of the season. This could be as simple as a light (1 – 33 percent), moderate (34 – 66 percent) or heavy (67 – 100 percent) estimate of forage utilized, based on a comparison to an un-grazed area. A grazing exclosure (area within pasture that is excluded from grazing) is a useful tool to compare how much has grown in comparison to how much is remaining in the pasture. Two steel posts and a wire panel tied in a circle makes an easy and effective grazing exclosure. In dry years, it is last year’s un-utilized portion that supplements the current dry year’s growth, protects the soil surface and improves infiltration when it does rain.
A grazing stick is another tool to measure forage production. It was originally developed for use in higher rainfall areas and monoculture pastures but can be adapted to other regions. The use of a grazing stick is dependent on appropriate local or regional calibration that reflects the leaf density of the pasture. Height of the forage in inches is converted to pounds of production per acre. Complete online directions of how to calibrate and use a grazing stick can be found at this site from the Noble Foundation http://www.noble.org/ag/forage/grazingstick/index.html. A minimum of 400-800 pounds per acre should be remaining after grazing in short grass regions.
Another method to measure utilization is quoted below and comes from a Nebraska and South Dakota resource entitled “Drought Management on Range and Pastureland: A Handbook for Nebraska and South Dakota.” This publication contains lots of good range management information that easily translates to western Kansas. Don’t let the title make you think it doesn’t apply, because if you are not in a drought, you are just preparing for the next one.
“Proper utilization during the growing season is generally the removal of 50 percent or less of the present, current year leaf and stem tissue by weight. A simple procedure can be used to develop a visual perception of percentage forage utilization. Clip the current year growth from random bunches or tillers at the ground level. Wrap the samples with string or tape. Balance the sample on your finger. The point of balance is the height at which 50 percent of the leaf and stem material would be removed. Clip the sample at this point and balance each half to estimate heights for 25 and 75 percent utilization. Since utilization often differs across the pasture, you will need to monitor average height of utilization throughout each pasture. Estimates of the stubble height at which a target level of utilization will occur should be made when the cattle enter each pasture.”
Take time at the end of the grazing season to evaluate the amount of grass utilized in relationship to the rainfall received and growing conditions. This will help build a good grazing management plan that can take advantage of additional growth when conditions improve and provides specific guidance when needed rains do not come.