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CIRCULAR 870, U. S. DEPARTMENT OF AGRICULTURE 



ranch stocking to these variations, efficiency in use of forage can be 

 increased. 



Effect of Site on Grazing Capacity 



Classification of the different kinds of range land will aid in making 

 the necessary adjustments. For example, on granitic soils — such as 

 those in the experimental pastures — herbage production is usually greater 

 on the more gentle slopes, apparently because the soils are deeper and 

 finer-textured than on steeper slopes. Obviously, this difference will 

 affect the grazing capacity of the land, and a means of classifying the 

 range according to such differences will improve the estimation of grazing 

 capacity. 



In evaluating the grazing capacity of the experimental pastures, it 

 was found that the land could be separated into six readily identifiable 

 site classes. These are: 



1. Swale. — The swale (drainage bottom) soil is typically a dark grey, 

 sandy clay loam with a fairly good water-holding capacity, as contrasted 

 to the shallow, brownish, sandy loams of low water-holding capacity 

 that are found on the slopes. The swales receive a considerable amount 

 of seepage water; in wet winters some portions remain saturated for 

 several months. Swales (figs. 8 and 9) consist of a heavy, poorly drained 

 phase, or wet swale, and a lighter, better-drained phase, or dry swale, 

 that usually borders the wet swale. 



Figure 8. — Narrow, ungrazed 



F-395852 



'wet swale" with exceptionally dense stand of perennial 

 rushes, April 1940. 



2. Gentle slope. — Located just above the swale, the fine sandy loams 

 of gentle slopes represent the transition from transported soil in the 

 drainages to soil developed in place on the slopes. Gradient is under 10 

 percent. 



