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, .,.,.". tAl t.a o 0') 1934. Before 1934, rangelands were grazed indiscriminately by large herds of cattle, sheep, and horses. The BLM has reduced livestock num- bers to the level of forage produced and designated ranges for use during the proper season. Grazing management systems designed to pro- tect the basic soil and vegetation resource have been implemented in some areas where funding and manpower have been provided. The Council for Agricultural Science and Technology (14) reports that the degree to which grazing enhances other resources depends on the kind of range, objectives of grazing management, and skill of range managers. In order to be effective, "grazing must be scientifically controlled and responsive to the needs of all users." Proper management of all kinds of grazing animals can be an effective salinity control practice. This management may include intensive grazing management programs or, in some , cases, temporary or total exclusion of livestock (2, 16, 18, 19, 32, '40). Adjustments in timing of grazing or numbers of animals may continue to be necessary in the future in order to protect the resources. However, adjusting livestock numbers alone is not the answer; grazing management systems whi ch meet the goals of the 1 and use pl an are also needed (25). , . The following are important factors which relate to the success of any grazing management system devised to reduce salt concentrations in sur- face runoff from rangelands: A. Intensity of Grazing The intensity of grazing can affect factors which cause increases in salinity. In an extensive review of the literature, Gifford and Hawkins (17) found that grazing influences infiltration. They note that it is "difficult to differentiate between the influences of moderate and light grazing," but that there "is a distinct impact from heavy grazing which is statistically different from that of light/moderate." Rauzi and Hanson (35) found a nearly linear relationship existed between increasing grazing intensity and decreasing rate of water intake. Knoll and 'Hopkins (23), Rauzi (33), and Rhoades et al. (37) found significant differences in infiltration rates between nongrazed and lightly or moderately grazed areas. Smeins (38) and Johnson (20) both state that grazing management practices designed to increase livestock production also have a definite impact on the interrelationships of soil, vegetation, and hydrologic processes. The degree of i nfl uenceupon hydro 1 ogi c responses is related to intensity of grazing, and the harmful effects of grazing are greatly reduced by light and moderate grazing. Rauzi and Hanson (35) found a significant relationship between species composition of grasses and grazing intensity. This work was later . supported by Hanson et al. (18). Heavy and moderate grazing resulted in a deterioration of vegetation from midgrasses to short grasses and sedges. Measurements recorded 97 and 80 percent composition of blue grama and buffalograss (short grasses) on the heavy and moderate grazing areas, respectively. Midgrasses (predominantly western wheatgrass) were maintained on the lightly grazed area. .j . '1 , i) 4 &1 1.. ;1-:, ~ ~-~"_.~ih-.~-ih M.- -._c,:,_;"...