Prescribed Grazing - Part 1
Mar 08, 2012
Prescribed Grazing Management - Part 1
The Natural Resources Conservation Service provides assistance to ranchers and farmers who wish to apply grazing management to their operation. The primary conservation practice used is prescribed grazing. Prescribed grazing is the vegetation management practice that is applied to all land where grazing is a planned use. The grazing may be from domestic livestock, semi-domestic animals (buffalo and reindeer) or wildlife. This practice has been developed to incorporate all the methods and concepts of grazing management.
Prescribed grazing is…
the controlled harvest of vegetation with grazing or browsing animals,
managed with the intent to achieve a specified objective.
The objectives developed with the rancher/farmer during the planning process determine the level of planning and detail necessary for the application of prescribed grazing. The minimum level of planning for the prescribed grazing practice includes enough inventory information for the landowner to know the proper amount of harvest to maintain enough cover to protect the soil and maintain or improve the quality and quantity of desired vegetation. The available forage and the number of grazing and browsing animals must be in balance for effective management of grazing lands. This is done by developing a feed, forage, livestock balance sheet. This part of the inventory identifies the available forage from the land and the demand for forage by the livestock and wildlife. It identifies where and when shortages or surpluses in forage exist.
Grazing is one of the major forces in defining which plant species will dominate a site. Different grazing pressures by different grazing and browsing animals favor different plant species. If the grazing is severe, undesirable plants are generally favored. Grazing management can be planned and applied that favors a particular plant community or species. This can be done to meet the objectives of the landowner and the needs of the resource.
Grazing management has been successfully planned and applied that has favored the re-establishment and increase in woody plants along riparian areas while still providing quality forage for the grazing animal. Where plants have died possibly due to overgrazing, recovery depends upon establishment of new plants. Although plants of the original community are invigorated by the reduction of grazing pressure and may suppress the successor species, the seedlings of the original species can become established in competition with the undesirable species only under favorable conditions.
Rate of plant regrowth following grazing is dependent on the amount of leaf area remaining for photosynthesis and the availability of active axillary buds to initiate new tillers.
Every management unit has certain characteristics that influence the distribution of grazing. Among these characteristics are soil, topography, size of pasture or feedlot, location of water, fences, riparian areas like tree and shrubbery plantings available through NRCS/FSA grant Programs like CREP, natural barriers such as strips of grass a minimum of 30' wide that animals are not granted access to, and the kinds and distribution of plants. In addition, weather conditions, insects, location of salt and minerals, type of grazing management being applied (frequency and severity of grazing such as "MOB" grazing) and habits of the grazing animals affect the pattern of grazing use.
For these reasons it is impractical to prescribe grazing use for every part of a large grazing unit, rotational paddock or feedlot or to prescribe identical use for all enclosures of a farm or ranch. Determining the key grazing area(s) in each enclosure and planning the grazing to meet the needs of the plants in the key area is more practical. If the key grazing area of a unit is properly grazed, the unit as a whole will not be excessively used. The key grazing area in a management unit is a relatively small area within the grazing unit. This key area is used to represent the grazing unit as a whole. Most plant communities in a grazing unit consist of several plant species in varying amounts.
Even though the entire plant community is of concern to management, to attempt to attain the desired use of every species would be impractical. It is more practical to identify a single species (or in some situations two or three) as a key species to serve as a guide to the use of the entire plant community. If the key species within the key grazing area is properly grazed, the entire plant community will not be excessively used.
Characteristics of a key grazing area:
• Provides a significant amount, but not necessarily the greatest amount, of the available forage in the grazing unit.
• Is easily grazed because of even topography, accessible water and other favorable factors influencing grazing distribution. Small areas of natural concentration, such as those immediately adjacent to water, salt or shade, are not key grazing areas, nor are areas remote from water or of limited accessibility. However, riparian areas are of special concern when establishing key grazing areas. Riparian areas are of generally small extent in relation to the surrounding landscape. These areas represent a significant resource in terms of forage production, buffering surface water flows, controlling accelerated erosion and sedimentation, capturing and transforming subsurface pollutants, and providing essential wildlife habitat and local biodiversity.
• Areas of special concern can also be designated as key areas. Areas of special concern could include habitat for threatened or endangered species, cultural or archeological resources, water quality impaired waterbodies and critically eroding areas.
• Usually limited to one per grazing enclosure. More than one key grazing area may be needed for an unusually large enclosure, enclosures with riparian areas, enclosures that have very rough topography or widely spaced water where animals tend to locate, when different kinds of animals graze the enclosure, or when the enclosure is grazed at different seasons. The entire acreage of small enclosures can be considered the key grazing area.
Key grazing areas should be:
• Selected only after careful evaluation of the current pattern of grazing use in the enclosure.
• Selected to meet the objectives and needs of the resources, livestock and landowner. Objectives and needs must meet the FOTG quality criteria.
• Changed when the pattern of grazing use is significantly modified because of changes in season of use, kinds or classes of grazing animals, enclosure size, water supplies or other factors that affect grazing distribution.
Degree of grazing use as related to stocking rates
Because of fluctuations in forage production or loss of forage other than by grazing use, arbitrarily assigning a stocking rate at the beginning of a grazing period does not ensure attainment of a specific degree of use. If the specified degree of use is to be attained and trend satisfactorily maintained, stocking rates must be adjusted as the amount of available forage fluctuates. When determining initial stocking rates, grazing distribution characteristics of the individual grazing unit must be considered.
Many methods are used to determine the initial stocking rate within a grazing unit. Often the past stocking history and the trend of the plant community are the best indicators of a proper stocking rate. The Multi Species Stocking Calculator in the Grazing Lands Application (GLA) software is one method for determining stocking rates, especially when the area is grazed or browsed by more than one kind of animal.
Prescribed grazing schedule
A prescribed grazing schedule is a system in which two or more grazing units are alternately deferred or rested and grazed in a planned sequence over a period of years. The period of nongrazing can be throughout the year or during the growing season of the key plants. Generally, deferment implies a nongrazing period less than a calendar year, while rest implies nongrazing for a full year or longer. The period of deferment is set for a critical period for plant germination, establishment, growth or other function.
Grazing management is a tool to balance the capture of energy by the plants, the harvest of that energy by animals and the conversion of that energy into a product that is marketable.
This is done primarily by balancing the supply of forage with the demand for that forage.
Such systems help to:
• Maintain or accelerate improvement in vegetation and facilitate proper use of the forage on all grazing units.
• Improve efficiency of grazing through uniform use of all grazing units.
• Stabilize the supply of forage throughout the grazing season.
• Enhance forage quality to meet livestock and wildlife needs.
• Improve the functioning of the ecological processes.
• Improve watershed protection.
• Enhance wildlife habitat.
Many grazing systems are used in various places. Prescribed grazing is designed to fit the individual operating unit and to meet the operator's objectives and the practice specifications. The basic types of grazing management systems follow. Many others can be developed to fit specific objectives on specific lands.
• Deferred rotation
• Rest rotation
• High intensity—low frequency
• Short duration