Remaining herbage provides an indication of rangeland health. Evaporation rates are high particularly in the Southern Great Plains. Leaving non-grazed herbage will slow evaporation and keep precipitation in the soil. Leaving more herbage also reduces the likelihood of overgrazing preferred plant species.
Plant litter and standing herbage should be uniformly distributed to reduce surface flow of precipitation and to moderate soil temperatures. Protection against wind erosion also requires an adequate combination of plant height and cover to reduce wind speed at the soil surface. Height of remaining herbage at the end of the growing season becomes increasingly important as the area of bare soil between plants increases.
The table (right) recommends optimal levels of nongrazed herbage. A grazing stick can be used to measure forage height and density. Photographic records of clipped plots will greatly enhance decisions on when to end grazing or when not to graze at all.
Use moderate stocking rates and seek the sage advice of "old timers" to minimize the risk of overgrazing find a Grazing Lands Group to mentor you in your state. Traveling through all your pastures with a mentor at the end of the growing season is an excellent way to learn more about what they "should look like".
Optimal Amounts of Residual Forage (oven-dry weight)
Desert - 250 lbs/acre
Shortgrass1 - 300-500 lbs/acre
Midgrass1,2 - 750-1,000 lbs/acre
Tallgrass1 - 1,200-1,500 lbs/acre
1To improve rangeland, leave the higher amounts of residue for each category.
2To promote midgrass over shortgrass, leave the higher amount of midgrass residue.
Hanselka, et al. (2001)