INCREASING PRODUCTION WITHOUT ACCELERATING EROSION 237 
the plant cover and cause accelerated soil erosion. Fencing or herd- 
ing so that grazing use is rotated between areas increases produc- 
tion and also provides more vegetation for soil protection. Allow- 
ing part of the range to rest during the growing season every 
second or third year results in a wider variety of the better forage 
grasses as well as greater forage production. 
In many cases, it is possible to take advantage of differences in 
the growth and palatability of forage species. In southern New 
Mexico, when black grama is grazed only during the non-growing 
season, almost twice as much herbage is produced as under year- 
long use. Under yearlong use the valuable black grama is replaced 
by worthless snakeweed (Gufierrezia spp.). It 1s possible to with- 
hold black grama areas during the growing season by grazing 
cattle on tobosa grass flats, which provide abundant palatable 
forage during the summer. Tobosa grass is not harmed by judi- 
cious summer grazing and is not palatable to cattle during the 
winter months. This pattern of seasonal use increases range pro- 
ductivity above that possible under yearlong use of either grass 
eyes (hs) 
Proper Distribution of Livestock 
Obviously, wells and stock tanks for water should be provided 
wherever possible so that animals can make effective use of the 
range. Well-spaced watering places aid in (1) distributing animals 
over the range, (2) preventing local overgrazing, and (3) keeping 
livestock in better condition. The number of cattle watered at a 
place should not exceed the grazing capacity of the area within a 
114- or 2-mile radius of the watering point. 
Judicious placing of salt grounds aids in drawing cattle to other- 
wise little-used parts of the range (12). The use of a mixture of 
cottonseed meal and salt as a self-feeding supplement promises to 
be an even more effective method of obtaining better distribution 
and thereby avoiding overused areas (2). 
Control of Noxious Plants 
The invasion of grassland by worthless or undesirable plants 
has resulted in a critical problem throughout much of the south- 
western United States (18). Increases in low-value shrubs on 
