BROOM-CORN EXPERIMENTS AT WOODWARD, OKLAHOMA. 5 



falls. The nature and distribution of the rainfall will be better un- 

 derstood by a careful study of the data in Table II, containing the 

 records of daily precipitation, with monthly totals, throughout the 

 five years from 1914 to 1918, inclusive. 



The annual precipitation has been sufficient to produce good 

 broom-corn crops in almost all the years during which these experi- 

 ments have been conducted, but in several seasons high yields and 

 brush of good quality were not obtained. These poor yields are 

 correlated in some measure with unfavorable distribution of the 

 larger and more important rains. 



Distribution may be unfavorable in several ways. Much of the 

 annual rainfall may come within a short period either at the begin- 

 ning, in the middle, or near the end of the season. The seasonal 

 rainfall may be sufficient in quantity but poorly distributed. Some 

 month may be unusually wet, followed by a long dry spell. Such 

 a condition occurred in 1914, when May was wet and June and July 

 were dry, and again in 1916, when June was wet and July was 

 entirely without precipitation. 



Still another condition may occur in which the rainfall is fairly 

 evenly distributed in point of time and about sufficient in quantity 

 and yet be unsuitable for crop production. This is when it occurs 

 in light showers which do not penetrate the soil and are soon evap- 

 orated. Showers amounting to half an inch or even more may add 

 little or no water to the soil if followed by high winds and bright 

 sunshine, which cause rapid evaporation. The season of 1918 is a 

 good example of this condition, as may be seen in Table II. While 

 a number of showers fell from June to August, inclusive, only two 

 afforded more than temporary relief to the crop. 



Table II. — Daily and monthly precipitation at Woodward, Okla., during the 

 5-year period from 1914 to 1918, inclusive. 



[Data (in inches) furnished by the observer of the United States Weather Bureau at 



Woodward. T= trace.] 



Date. 



Jan. 



Feb. 



Mar. 



Apr. 



May. 



June. 



July. 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



1914. 

 1 











T 

 2.00 

 .06 

 T 

 T 

 T 

 T 



T 

 T 



0.04 



.07 

 .04 













2 









0.11 



.25 



T 











3 











T 

 T 







4 









T 



T 

 0.31 









5 





0.04 

 T 



T 



.22 

 .14 

 T 



T 

 T 

 T 

 T 



T 

 .55 







6 



0.31 



1.25 



.06 



6.05 



.06 

 .02 



T 



T 



7 



8 

























.80 









10 











.10 













T 

 T 



11 



0.18 







.87 











.29 





12 



.02 



.08 













.02 

 .08 

 T 



13 















T 



T 





14 









T 



.36 

 .03 

 .04 

 .19 





















0.57 

 .03 











.06 



T 

















.38 







17 





.25 



.12 





.22 

 .02 



T 









T 

 T 



18 



T 











