44 BULLETIN 1405, U. S. DEPARTMENT OF AGRICULTURE 



will be so seriously overgrazed as to offset the benefit to the re- 

 served area. 



Deferred grazing has been applied on national-forest range in 

 the West so widely and for so many years that the good results 

 to both stock and range are indisputable. Improvement is invariably 

 rapid where there remains a fair stand of seed plants. Naturally, 

 considerable time is required to increase appreciably the forage 

 cover on lands which for many years have been in a low state of 

 productivity, and especially on those which support few highly 

 palatable seed plants. Without the adoption of some grazing plan, 

 however, such as deferring the cropping until the seed of the more 

 desirable palatable vegetation has matured, or decreasing materially 

 the number of livestock formerly grazed, or actually removing the 

 animals for a year or more, there is little chance of increasing the 

 range returns from badly depleted lands, of controlling erosion, or 

 of improving the efficiency of important watersheds in one way or 

 another. Any kind of plant cover is preferable to denudation or to 

 the production of a growth so sparse that the fertility of the soil 

 tends to decline rather than improve, 



SOIL FEKTILITY AND FORAGE TYPE 



It is well known that different species or types or vegetation vary 

 considerably in the quantity of water they require and in the type 

 of soil necessary for their development (7). The earlier stages of 

 plant cover, such as are found on semidecomposed soil, poor in 

 organic matter and comparatively low in available moisture, con- 

 sist of shallow-rooted early-maturing annual species. Although 

 widely spaced at first, these plants gradually increase in density 

 until practically all of the available soil moisture is used up by 

 the vegetation. When this annual plant growth reaches maturity 

 and dries up, a large proportion of the soil surface is exposed. (PI. 

 V, fig. 1.) Small protection is thus given the soil by annual vegeta- 

 tion as compared with that given by perennials. Not only does the 

 range which supports annuals ordinarily furnish only a small quan- 

 tity of rather inferior forage, and practically none unless cropped 

 when the leafage is succulent, but it must be grazed lightly and with 

 more than usual care. Where deferred grazing is applied for several 

 years in succession, however, even lands on which annuals predom- 

 inate show improvement in the plant cover. Eventually the vegeta- 

 tion changes to a more permanent or stable type, and the quantity 

 of palatable herbage is correspondingly increased (£, pp, 1-7). 



RESEEDING TESTS OX PROTECTED AXD DEFERRED GRAZED PLOTS 



In order to determine the time required to revegetate lands in 

 different degrees of depletion, both protected and unprotected exper- 

 imental plots varying in size from a few square feet to several 

 acres were established in each of the major zones and forage types 

 and on different slopes and exposures. The density and compos- 

 ition of the vegetation on these plots were carefully recorded, the 

 quadrat plan of mapping being used with adaptations. On the 

 larger plots the plant associations which made up the cover were 

 merely outlined and the species and the density of each recorded. 



