2 BULLETII^ 367, U. S. DEPARTMENT OF AGRICULTURE, 



to as nearly the same treatment as the adjacent unfenced range 

 received as was possible nnder the circumstances. When these ex- 

 periments were begun in 1903 the problems which presented them- 

 selves for solution were as follows : ^ 



(1) To demonstrate that under proper treatment run-down and overstocked 

 ranges will recover, a statement of fact that was very much doubted by stock- 

 men when the experiments were begun. 



(2) To ascertain how long a time is necessary to get appreciable and com- 

 plete recovery, and what methods of management will produce such results. 



(3) To carry on reseeding and introduction experiments in the hope of 

 increasing the total quantity of feed. 



(4) To measure as accurately as possible the carrying capacity of a known 

 representative area. 



Results have already been published - relating to the first three of 

 these questions. The present bulletin presents the data on carrying 

 capacity which have been obtained so far. The methods of making 

 collections originally established ^ have been continued. Haj^-cutting 

 operations have been carried on for five years, and records of the 

 number of " animal-days' " feed ^ used on measured areas of the 

 reserve have been obtained by recording the number of stock on 

 given areas for a period of seven years. From the haj^-cutting rec- 

 ords and the estimates based upon the collections an estimate of the 

 carrying capacity is made, and this is compared with the actual 

 results obtained from the pasturing records. Some additional mis- 

 cellaneous observations relating to the project are included. 



The generalizations presented here apply strictl}^ to the area in- 

 dicated on the map. They could be applied without modification to 

 exactly similar localities and conditions. They doubtless present a 

 statement of conditions closely similar to those on many other parts 

 of the southwestern arid grazing land ; they will be usable with but 

 slight modification over most of southern Arizona, and to some ex- 

 tent in New Mexico and western Texas. 



Three maps of the area studied are given for the better under- 

 standing of the region. One of these (fig. 1) presents the main re- 

 lief features of the reserve, being based upon the Patagonia quad- 

 rangle of the United States Geological Survey contour map of the 

 Santa Eita Mountain region. Another is an outline map (fig. 2) 

 that shows wdiere collections of material were made. The small 

 letters (without accent) refer to the spring collections made in the 

 years 1903 to 1908, inclusive. The accented small letters refer to the 



1 See Bureau of Plant Industr3' Bulletin 67, preface. 



= See Bureau of Plant Industry Bulletins 67, 117, and 177. .^_„ 



2 See Bureau of Plant Industry BuUotin G7, p. 24 et seq. 



* As used in this bulletin, an " animal-day's " feed equals the feed necessary for one 

 mature animal, cow, steer, bull, horse, or burro, for one day. Calves or colts when six 

 months old ai-e counted as mature animals, but are not counted at all before that time. 



