YIELD OF VEGETATION. 



19 



This lupine is an annual plant which grows in the winter rainy 

 season. It is conspicuous in the southern portion of the inclosed 

 area in February and March. In favorable seasons it gives its char- 

 acteristic blue color to the landscape upon hillsides and bluffs along 

 arroyos. Even this plant is closely grazed by cattle, with, as already 

 stated, apparently no injury. Upon the outside of the area it is 

 grazed as closely as any other forage plant and seems to be as readily 

 destroyed by such grazing as any of the valuable feeds. In the 

 spring of 1908 it was difficult to find any of this plant outside of the 

 fence in localities where it has been very abundant. The rayless 

 golden-rod is the only conspicuous weed not touched by stock. 



YIELD OF VEGETATION. 



During the time that the area has been under fence an effort has 

 been made to get a quantitative estimate of the amount of herbage 

 produced from year to year. The estimate is based upon measure- 

 ments of definite plats scattered over the entire field in such a way 

 as judgment dictated would give an average yield. Only the briefest 

 outline of the data secured is given here. The method of measure- 

 ment is given in Bulletin 67 of this series and need not be repeated 

 here in detail. In general it may be said that the vegetation of plats 

 containing 21 square feet was measured, these plats, eighteen to 

 twenty in number, being scattered over the entire field, as indicated 

 in Bulletin 67. In that publication a more or less detailed discussion 

 is given of methods employed in making these computations, which 

 need not be repeated here. Inasmuch as these are more or less esti- 

 mates anyway, it is not important that in this paper a slightly differ- 

 ent method of computation is used from that in Bulletin 67. The 

 comparisons are not altered. 



The results of these measurements are given in the following table : 



Table I. — Average yield of forage on plats of 21 square feet each in the fenced area on the 



Coronado National Forest. 



Year. 



vm /Spring... 



iytw (Summer. 



1004 (Spring... 



1 J " 4 \Summer. 



in 5 '/Spring... 



1905 \Summer. 



iqofi If Spring... 



lyub liSummer. 



ion? [Spring... 



iyu/ iSummer. 



1908 Spring... 



lJU8 \Summer. 



Season. 



Rainfall. 



Seasonal 

 yield. 



Inches. 

 3. 29 

 7.48 

 2. <i4 

 8.24 



20.70 

 6.14 

 9.88 

 3.27 

 7.98 



12.03 

 9.36 



10.67 



Pound.?. 

 520. 55 

 270. 47 

 14.13 

 398. 32 

 799. 00 

 375. 94 



• 00 



435. 88 

 715. 88 

 300. 88 

 924. 07 



Annual 

 yield. 



Pounds. 



791.02 



V 412.45 

 | 1,174.94 



00 

 | 1,151.76 

 | 1,225.55 



177 



a Xo measurements. 



