INTRODUCTION 



During the past decade, the author has stud- 

 ied infiltration and erosion potentials of seven 

 diverse summer ranges and has related these to 

 cover, soil, and topographic parameters by 

 means of multiple regression analyses. Accepta- 

 ble regression equations relating infiltration to 

 site factors were developed for three of the 

 areas (Meeuwig 1969, 1970a), but the regres- 

 sion equations developed for the other four 

 lacked precision and contained anomalous 

 relations. 



Satisfactory regression equations relating 

 erosion to site factors were developed for each 

 of the seven areas (Meeuwig 1970b). Unlike the 

 infiltration equations, the general relations de- 



fined by these equations did not differ greatly 

 from area to area. In essence, these equations 

 indicate that erosion potential (as measured in 

 these studies) depends chiefly on cover and 

 slope gradient; and that differences in the 

 cover-slope-erosion relations, both within and 

 among study areas, are attributable to varia- 

 tions in soil properties, notably organic matter 

 content and texture of surface soils. 



This paper reports the results of combining 

 the data from all seven study areas to determine 

 the general influences of cover, slope, soil tex- 

 ture, and organic matter on soil stability over 

 the range of conditions encompassed by these 

 studies. 



All the study areas have herbaceous cover 

 and all are grazed by livestock during the sum- 

 mer, except the Davis County Experimental 

 Watershed from which grazing has been pro- 

 hibited for more than 30 years. Their locations 

 are shown in figure 1. Areas studied were: 



1. — Great Basin Experimental Range, 

 Manti-LaSal National Forest, central Utah. Ele- 

 vations of the 162 study plots varied from 

 7,000 to 10,000 feet. This sheep range has a 

 wide variety of grass and forb species. Soils are 

 mostly silty clay loams and clay loams derived 



from limestone, shale, and sandstone. 



2. — Davis County Experimental Water- 

 shed, Wasatch National Forest, northern Utah. 

 Elevations of the 80 study plots varied between 

 8,000 and 9,000 feet. This area was the source 

 of serious floods during the period 1923 

 through 1930. Much of it was contour trenched 

 and seeded with grass from 1933 through 1936. 

 Grazing has been prohibited since 1933. Soils 

 are mostly silt loams and loams derived from 

 gneiss, schist, conglomerate, sandstone, and 

 shale. 



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