8 
BFLLETIX 976, r. S. DEPARTMENT OF AGEICUETVEE. 
seasonal rainfall, the varying quantities deposited by different showers 
and the manner in which it falls are not shown. These will be better 
understood by a careful study of the data in Table II, which contains 
a record of the daily rainfall, with monthly totals, throughout the 
6-year period from 1914 to 1919, inclusive. 
The annual and seasonal rainfall was sufficient to produce fair to 
good yields of the grain-sorghiun crops in all the years during which 
these experiments were conducted: but in several seasons the low 
}-ields obtained were due largely to the unfavorable distribution of 
the moisture. This may occur in several ways: (1) Much of the 
1 PR£C/p/r^r/ON 
! 
1 
i 
\ 
; 
P 
d 
1 
1 
/^P/?IL M^Y JUNE JULY / 
7aG. SEPT. 
Fig. 4.— Average monthly precipitation and evaporation, in 
inches, at the Amarillo Cereal Field Station during the 
growing season (April to September) in the 7-year period 
from 1913 to 1919, inclusive. 
annual rainfall may come within a short period, either near the 
beginning, in the middle, or at the end of the year: (2) the seasonal 
rainfall may be sufficient in quantity but poorly distributed; or (3) 
the rainfaU may be fairly evenly distributed and about sufficient in 
quantity and yet be unsuitable for crop production, as when it occurs 
in light showers which do not penetrate the soil and are soon evapo- 
rated. The seasons of 1916 and 1918 are good examples of the last- 
mentioned condition. Showers amounting to less than half an inch 
may add little or no moisture if followed by high winds and bright 
sunshine, which cause rapid evaporation. 
