18 



BULLETI]^ 1031, U. S. DEPARTMENT OF AGRICULTURE. 



plan of management in order to avoid local overstocking to the 

 detriment of stock and range. 



The possible extent of this local variation in precipitation is ap- 

 parent from observations at the Jornada Range Reserve and vicinity 

 from 1915 to 1919. In 1918 four additional rain-measuring stations 

 were established on the reserve at distances of T to 13 miles apart. 

 Table 5 shows precipitation at these stations in addition to the head- 

 quarters and State College stations. 



Table 5. — Annual and seasonal (July, August, afid September) precipitation for 

 New Mexico State Agricultural College and five rain stations on the Jornada 

 Range Reserve, shoiving variation in amount loithin comparatively short 

 distances. 





Agricultural 

 College. 



Headquar- 

 ters. 



South Well. 



Red Lake. 



West Well. 



Ropes Spring. 





An- 

 nual. 



Sea- 

 sonal. 



An- 

 nual. 



Sea- 

 sonal. 



An- 

 nual. 



Sea- 

 sonal. 



An- 

 nual. 



Sea- 

 sonal. 



An- 

 nua!. 



Sea- 

 sonal. 



An- 

 nual. 



Sea- 

 sonal. 



1915 



Inches. 

 7.37 

 7. 78 

 5.58 

 7.23 

 8.05 



IrtcJie's. 

 4.67 

 2.47 

 4.91 

 2.71 

 4.20 



Inches. 



1 7. 51 

 8.88 

 3.54 

 8.76 

 12.78 



Inches. 

 4.86 

 2.58 

 2.34 

 4.41 

 8.20 



Inches. 



Inches. 



Inches. 



Inches. 



Inches. 



Inches. 



Inches. 



Inches. 



1916 



















1917 



















1918 



5.47 



7.72 



2.39 

 4.67 



7.06 

 11.52 



3.88 

 6.42 



5.87 

 7.91 



3.16 

 4.96 



8.89 

 16.37 



3 70 



1919 



5 85 







1 Approximate. 



Although no precipitation records are available, it is known from 

 observations that the range unit adjoining the reserve on the south 

 received more precipitation during 1917, a year of the recent drought, 

 than fell on the reserve. In 1919, however, it probably received less 

 precipitation than the reserve by an amount sufficient to make a dif- 

 ference in the current year's forage and in recuperation of range. 

 The range unit north of the reserve received earlier rains and a 

 greater total precipitation than the reserve in 1918 and 1919, a dif- 

 ference of sufficient importance to warrant a change from the pre- 

 arranged plan of grazing the unit. 



This possible variation is pointed out merely as one of many 

 warnings against too heai^y stocking of a range unit as a whole or a 

 plan of management which is not reasonably flexible to meet such 

 a situation by shifting stock from a local drj^ area to one of more 

 abundant rainfall without disarranging the whole plan. 



VARIATION IN FORAGE PRODUCTION. 



Some nueasure of the volume of range forage which ma}' be figured 

 on seasonally, annually, and over a period of j^ears, and the main 

 factors responsible for variation, are fundamental in deciding the 

 classes, numbers, and management of liA'e stock. Drought and im- 



