EFFECT OF GRAZING Il7 



really relished even by sheep. Because of the attending difiS- 

 culty of utilizing it early enough, much of the forage, poor though 

 it be, is lost each year. Then, too, on account of the restricted 

 taproots of the conspicuous vegetation and the heavy erosion to 

 which the lands are subjected in the absence of an abundance of 

 soil-binding roots, it is essential that stock grazing upon this type 

 be handled in a most careful manner. If serious erosion is to 

 be prevented, the lands should be cropped very little, or better 

 still, not at all, until a good scattering of the second weed stage 

 vegetation has gained dominion over the soil. 



EFFECT OF GRAZING ON THE DEVELOPMENT OF 

 VEGETATION 



The statements as to the depletion of the different plant 

 stages make clear the fact that grazing may either retard or 

 promote the development of the plant cover and cause what 

 plant ecologists term vegetative degeneration or progression. 

 The highest grazing efficiency consists in taking the largest 

 amount of forage from a pasture year after year. Therefore 

 any system of pasture management which is responsible for 

 a decline in the forage crop from season to season is destructive. 

 If such a practice is persisted in, the ground cover is soon de- 

 stroyed, and this condition sooner or later is followed by erosion 

 in one form or another. 



A typical case depicting the effects of range depletion and 

 erosion is shown in Figure 34. It will be noted that where the 

 original cover remains intact (section B, to the extreme left in 

 the figure) the vegetation is of a desirable forage type and no 

 erosion has occured. Moderate destruction of the vegetation 

 (to the extreme right of section B) has brought forth a somewhat 

 inferior type of plant Hfe, and the soil is subject to at least moder- 

 ate erosion. In contrast to these conditions, serious destruction 

 of the cover (section A) is associated with heavy washing of the 

 soil. The vegetation on the moderately depleted areas (to the 

 extreme right of section B) consists chiefly of plants of the 

 second weed stage, but on the badly eroded parts (section A), 

 the cover is composed either of plants of the first weed stage or of 



