Rangeland Status and Restocking Strategies Following Drought
May 21, 2004
Rangelands in Colorado, especially eastern and southwestern Colorado, have suffered tremendous setbacks in vegetation vigor and/or loss of perennial plants due to drought conditions which in some areas have existed for at least four years.
Currently, much of eastern and southwestern Colorado is in a continuing drought. The onset of the drought began in 2000 causing many rangeland areas to have appreciably less forage in that year, and placing stress on perennial plants. During 2001, precipitation was fair to moderate, depending on the area of the state. The year 2002 was the driest on record in Colorado. Perennial grasses did not grow at all that year.
Fall and winter 2003 provided marginal encouragement to range managers, but reasonable to very good spring rains did provide up to a 40-60 percent forage crop in the 2003 growing season for those ranchers who had adjusted their stocking rates early to match the forage availability. Many areas of rangeland lost much of the perennial grasses, especially warm season grasses. Estimates are that on average 35 percent of the blue grama died in 2002. Current estimates of blue grama loss range from 30-80 percent due to the continued lack of moisture on much of Colorado’s rangelands.
Many, if not most, ranges were very weedy in 2003. Annual weedy plants responded to the additional moisture and the lack of perennial grass competition. The weedy plants further reduced the moisture availability for perennial grasses. This means that the recovery that might have occurred in 2003 was slowed.
For the 2004 grazing season, expect major reductions in the forage available and poor plant performance even with normal precipitation. The drought has caused a decrease in production from cool season grasses, such as western wheatgrass, green needlegrass, and needleandthread. Before the rangeland can recover, soil moisture must be restored. This means it has to rain. Moisture is critical to increase and maintain vegetation on the soil surface. This applies to plant cover and litter.
The timeline for full recovery depends on a variety of factors. Vegetation that was healthy before the drought and was grazed more lightly during the drought will recover far more rapidly than forage that was not afforded these breaks. Implementing a prescribed grazing management system will help provide the recovery opportunity from grazing the land needs. The difference may be that those rangelands that are managed well may approach 75 percent capacity in three years and will be near full capacity within five years. Those rangelands that continue to be heavily grazed will take 10 or more years to recover and will be less than 50 percent capacity in five years. Evaluating and monitoring rangeland allows ranchers to determine how well the range is recovering.
Ranchers also need to stock or restock appropriately—according to the expected forage availability and to enhance plant maintenance and recovery. Remember, the "real or actual" stocking rate is the forage demand (how many animals eating how long) relative to the amount of forage on the range.
For further information on how to set up a prescribed grazing management system or on how to monitor your rangeland, please contact your local USDA Natural Resources Conservation Service (NRCS) field office or Colorado State University Cooperative Extension office. Also check out the Colorado NRCS website at www.co.nrcs.usda.gov under Public Affairs News and Events to find copies of Grazing Lands Conservation Initiative Technical Notes (under Colorado Drought) that provide information on restocking strategies, prescribed grazing, and monitoring rangeland.