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~. O".l Co co The objecti ve of good grazi ng management is a maxim.urn forage cover on the rangeland for production of meat and other useab1e products. Maximum forage usually trans1 ates into maximum vegetative cover which in turn means reduced runoff, increased soil stability, and improved water quality. This conforms to goals of the Clean Water Act. IV. CURRENT SITUATION 1. Range Condition Rangelands provide water, energy, minerals, recreational opportunities, and habitat for wildlife in addition to grazing for domestic livestock. When properly managed, the renewable vegetative resource provides economical forage for the production of cattle and sheep and a protectiye soil mantle that holds the land in place. If misused and overgrazed, productive rangeland can become a wasteland where accelerated runoff may create massive erosion and turn dry channels and streams into silt-laden torrents, carrying tons of sediment to the lowlands and increasing flood damage to adjacent farm lands and urban areas. Plant physiologists are in general agreement that removal of plant tissue by grazing or other means is a physiologically destructive process to plants. Loss of leaf tissue disrupts the photosynthetic process which causes a decline in p'lant growth. Continued excessively heavy grazing depletes food reserves stored in plant tissue, the root system is weakened and dies back from the tips toward the root crown and eventually the plant dies. On the other hand, moderate grazing use (usually about 50% of current annual growth) is not damaging to range forage plants. Grazing is a natural element of the ecosystem and, range plants which have eyol ved over the centuri es undergrazi ng have marvelous recuperative powers. When grazing use is managed to accommodate the physiological requirements of pl ants, a vi gorous vegetati ve cover can be maintai ned. The above ground parts of pl ants give protection to the soil surface by reducing raindrop impact and overland flow, and their root systems serve as binders of the soil mantle. Plant litter and small fragmented rock (desert pavement) also protect the soil surface, and the addition of organic matter improves infiltration and decreases overland flow. Erosion is a function of the amount of exposed soil and is further strongly influenced by the intensity and duration of rainfall and steepness of topography. Raindrop impact is the initiating force in surface movement of soil. Maintenance of a vigorous perennial plant cover, then, is vital 'to soil stability and becomes increasingly important as slope steepness increases. Soil texture is also a factor. Soils with a high content of fine sand or silt erode most readily. - 6 -