INCREASED CATTLE PRODUCTION. 3 







and demonstrations in range management under conditions existing 

 in southern New Mexico and similar country in adjoining States. 

 The boundaries were slightly modified by Executive order of April 24, 

 1916, and at present include about 200,000 acres. 



The eastern portion of the area, comprising about one-fourth of 

 the total, is rough and broken and includes the west slope of the 

 San Andreas Mountains, which reach a maximum elevation of about 

 7,600 feet, both slopes of a narrow belt of rough, gravelly hills just 

 west of the main mountains, and a series of narrow, poorly defined 

 valleys between the two. The remainder of the Reserve is a com- 

 paratively flat, or slightly rolling, plain, lying between elevations of 

 about 4,100 and 4,700 feet, and broken only by a small mass of 

 igneous mountains, the Dona Anas, at the southwest corner. 



The locality is one of the most arid in the Southwest. Records 

 for 55 years at Mesilla Park, about 15 miles southwest of the Reserve, 

 show an average annual precipitation of 8.63 inches, with precipita- 

 tion for individual years as much as 17 inches and as little as 3.50 

 inches. Temperatures as high as 106 are common in summer, and 

 the region is subject to almost continuous high winds and, conse- 

 quently, high evaporation. The soils of the plain are rather coarse 

 to medium textured wind-blown sands, with patches of heavy adobe 

 clay, usually with a rather high percentage of alkali, where water 

 often stands until evaporated. The soils of the mountains and the 

 outwash plains flanking them are coarse sands and gravels. 



Naturally, with this combination of poor soils, low precipitation, 

 high temperatures, and high winds, the vegetation is comparatively 

 thin and made up of drought-resistant, semidesert species. By far 

 the greater part of the forage, perhaps 80 per cent, is furnished by 

 perennial grasses, of which the most important are the grama grasses, 

 three-awn, tobosa, drop-seed, muhlenbergias, burro grass, and wolf tail. 1 

 On large areas of the foothills and mesa, black brush, creosote bush, 

 and mesquite predominate; but black brush and creosote bush are 

 worthless as forage, and the mesquite is of low value. In figure 

 2 the vegetation is classified into range types for all of the Reserve 

 except the mountain portion. 



i Black grama (Bouteloua eriopoda) is the most important grass on the reserve. Tlue grama grass (B. 

 gracilis) and hairy grama grass (B. hirsuta) are found only in the mountains and foothills- E. curtipendula 

 is found in the mountains and on the mesa. 



Next to the grama grasses in importance are three-awn grasses (known locally as "needle grasses") 

 Aristida longiseta, A. pcnsa, and A. purpnrea. 



Tobosa grass (Hilaria mutica). 



The drop-seed grasses include several species, the most important being Sporobolvs cryptandrus, S. flex- 

 uo&us, S. wrightii, S. airoides, S. auriculatus. 



The most important species of muhlenbergias are Muhlenbergia gracillima, and Af. porteri. 



Burro grass (Sclcropogon brevyolius), 



Wolftail (Lycufus phUcides). 



Blackbrush ( Flourensia cernua). 



Creosote bush ( C'ovillea glvtinosa). 



Mesquite (Prosopis glandulosa). 



