MARCH 2001 BACK ISSUE
Horse Previews Magazine website - Posted on 03/07/2001; 2:00:00PM.
Important Principles for Managing Grazing Animals in Riparian Areas
Jeffrey C. Mosely, University of Idaho
A successful grazing management strategy creatively combines these principles into a plan designed to meet an area's unique circumstances. Consequently, there is no one grazing strategy or system that is "best".
Timing of Grazing: Avoid repeated grazing during critical stages of plant growth. The most critical stages are whenever plants are initiating new growth. This includes new growth in the spring or fall and whenever plants are trying to regrow after previous grazing. New plant growth requires energy from the plant and at some point in time, the plant needs a chance to replenish the energy used. To produce energy a plant needs ungrazed leaf tissue. Also, avoid grazing when soil moisture is high and soils are more susceptible to trampling damage.
Frequency of Grazing: Avoid grazing too often during a single growing season. If given an opportunity to regrow and replenish its energy stores, a plant can be grazed several times during one growing season. If grazing is too infrequent, some plants will become "choked" by too much dead material and subsequent plant growth will be restricted. Too long ungrazed periods can inhibit bird nesting and also will cause the vegetation's nutritional quality to decline.
Severity of Grazing: Avoid removing too much of the plant's leaf area. Leaves are the main sites of energy production for the plant. Without sufficient leaf area remaining after grazing, the plant will be unable to regrow and replenish its energy reserves. It also is important to leave enough plant material to hold the soil in place, to filter nutrients and sediments, and to protect the plant's roots and stem bases from excessive cold or heat.
Season of Grazing: Avoid grazing in an area at the same time of the year, year after year. Some plants can cope with this better than others, but varying the season of grazing from year to year is recommended for most kinds of plants. If altering the grazing season is not possible, the severity or the frequency of grazing may need to be reduced. To prevent sheet erosion of feces into surface waters, grazing should be avoided near surface waters when soils are frozen.
Animal Distribution: Prevent large numbers of animals from congregating. If grazing animals are causing soil or plant damage, it is often a problem of poor animal distribution rather than too many animals.
Number of Animals: This is probably the most important decision with any grazing plan. Too many animals will cause animal performance to decline, but the soil and vegetation will have deteriorated before animal performance begins to suffer. Most grazing plans that include strategically timed ungrazed periods during the growing season will, over time, support more animals than grazing systems where pastures are grazed continuously throughout the growing season.
Flexibility: Flexibility is critical. Animal grazing must be managed according to the varying plant, soil, and animal conditions that exist, not according to specific calendar dates. Even the most well developed grazing plan will continually require some adjustments.