30 



EANGE INVESTIGATIONS IN ARIZONA. 



The following table giving totals computed from the preceding 

 tables is more convenient of reference and shows in connection with 

 liguro 1 the relative productivity of different portions of the field: 



Totals compiled from previous tables. 



The last column of this table is of special interest. It shows a wide 

 variation in the quantity of vegetation which is produced even in 

 areas situated near each other. It must be borne in mind that the 

 most productive plots represent comparatively small areas. The 

 tables also show a greater average of summer growth, the average for 

 the spring being 270 pounds per acre and for the summer season 799 

 pounds, or an average for the entire year of 1,069 pounds per acre. 



In interpreting these figures it must be remembered that they rep- 

 resent very closely the total herbaceous growth and that some of the 

 plants listed are not eaten by stock when there is more palatable feed 

 to be had, while others are eaten only in part. In estimating the 

 amount of stock feed, therefore, it is necessary to make a liberal 

 deduction from the above figures. The method of making the estimate 



