12 BULLETIN 728, U. ' S. DEPARTMENT OF AGRICULTURE. 



of southwestern New Mexico and adjacent Arizona usually grow on 

 soil that is moderately fine, sometimes gravelly, but generally not 

 rocky nor very sandy. In places there are large patches of it, suffi- 

 cient to feed several thousand head of cattle for several months, but 

 the total amount of this feed both in Texas and New Mexico is quite 

 limited. 



All the other species of these curious desert plants grow on rocky 

 hillsides and slopes where the soil is coarse talus or merely piles of 

 stones with a little soil mixed in. Lechuguilla grows only on limestone 

 soils, but will cover hillsides, ridges, and table-lands where the lime- 

 stone is but scantily covered with soil. 



Only a relatively small part (at a rough estimate not over 25 per 

 cent) of the land in the regions indicated on the map carries a crop of 

 the species ascribed to it. Over much of the sandy land the principal 

 plants are grasses ; on the tight soils few or none of these shrubs grow; 

 while much of the gravelly mesa area is occupied by creosote bush or 

 black brush with only an occasional yucca. The heaviest growth of 

 soap weed ( Yucca data) is to be found in the region between El Paso 

 and Lordsburg and in the open plain between El Paso and Alamogordo. 



Exact data as to the amount of feed found on an acre or a section 

 are not available, and estimates by different men who have been 

 cutting it vary from 3 tons per acre down. Cuttings made over 35 to 

 40 sections near Newman, N. Mex., yielded from 175 to 300 tons of 

 dry leaf heads, with an average of 250 tons per section. The man who 

 was managing this cutting estimated the dry stalks at approximately 

 as much more in weight per section. These plants are usually shred- 

 ded and fed while fresh, and the green weight is doubtless at least 

 twice that of the dry leaves and stalks. From these figures we reach 

 the conclusion that in regions where these plants are tolerably abun- 

 dant the yield of fresh feed averaged \\ to 2 tons per acre. Actual 

 weights of two loads, each consisting of 38 stalks, averaged 1,340 

 pounds. An acre with an average stand of the growth found on the 

 plains northeast of Las Cruces, N. Mex., in 1914 produced 85 stalks 

 by actual count, which would weigh about \\ tons. These figures 

 are obtained from land where the plants of this species were of medium 

 to large size and fairly abundant. 



Yucca glauca, the bear-grass of the Staked Plain region and north- 

 ward, produces from one-fourth to 1 ton per acre of dried material, 

 according to Mr. J. E. Wallis, of Elida, N. Mex., who had cut and 

 baled between 3,000 and 3,500 tons (dry) of it on contract. Allowing 

 for the loss of moisture, which would be at least 50 per cent, this 

 species in eastern New Mexico produces from 2 tons per acre on lands 

 carrying a heavy stand down to nothing on the tight lands. 



With the exception of occasional small patches of old sotol, none of 

 the other species produce as much feed per acre as the soap weed, and 



