Heavy grazing 
 
I. Decreased aensity, 
2. Increased the number of aub-types of vegetation. 
3. Compacted the soil. 
4. Decreased absorption, so that 
(a) A lesser storm produced surface runoff. 
(b) The total surface runoff in a year was greater. 
5. Increased the percenrt- of silt in the runoff. 
6. Increased the amount of silt tbrough making the 
runoff greater (4b) and more frequent (4a)., 
7. Increased leaching of plant foods from soil, so 
that 
(a) It took more rain to start growth. 
(b) Volume and quality, of feed decreased. 
D-3 grazing studies have definitely indicated that all of 
the above conclusions are true of the Southwest except (7) uhich 
has not been specifically studied, but which probably also holds 
true. 
Lo    v    p__ Genea Overpazing   Practically none of our 
southwestern ranges have been uniformly -under or overgrazed.  Scarci- 
ty of water and the exigencies of topography, palatability, seasonal 
use, density of forest cover, rainfall,, class of' stock, and methocs 
of handling have almost always resulted in overgrazing some places 
and kinds of forage and often in undergrazing others. 
Accordingly practically all ranges have developed overgrazed 
spots, whether or not overstocked, and the overstocking which has 
taken place on nearly all raviges at some time during their histo'y 
has merely increased the number of spots and the intensity of over- 
gra7ing on them. 
It is likewise true that the erosion on an overgrazed spot 
will ofiten gradually exte-A  ts lf to areas not overgrazed.  Such 
extension may reach fo- a lorg Cstanse, especially on watercourses. 
Pny practical progam of prevention or control must, therefore, 
Orksl at the start with stock distribution and methods of handling. 
Even heavy reductions will afford only partial relief if the 
reduced numbar is allowed to merely overgraze a smaller area instead 
of to lightly graze the wlole area. 
The whole erosion tituation constitutes a ch-allenge to tLo sldJi 
of stockman mid grazing administrators in -evising methods which ill 
avoid overgrazing, local as well as genoral,