CEREAL EXPERIMENTS AT THE WILLISTON SUBSTATION. ab 
erowing season (April to July, inclusive) was 8.86 inches. The 
maximum for any one growing season was 15.44 inches (in 1906) and 
the minimum was 3.73 inches (in i883). 
The rainfall is presented in graphic form in figure 1. The entire 
height of the vertical columns represents the precipitation in inches 
for the different years and the black lower portion shows the rain- 
fall for the growing season (April to July, inclusive) for the same 
years. The lower horizontal line represents the average seasonal 
24 = 
22 ; 
ny 22 z | 
N /6 \ N RS ; 
R ve a = N BSN Ne 29 NAc 
Se {R N-Ne NNNV\Bs__RNNS 
NSAINNNS | \N NN NN NNEPS BSNS oo 
7O WINNS INT NI SNUBS NSN SNE gg SEASO 
M2) 3 NNN 1 INIS CRIN RST SD a Nwe INIS INN INS BNC? 4V474ce 
NBAINNNN | SSNS NY | NINT NS SS AS BS 
NBR ASS EELEEEL RT Nace aeeRe 
NII EEE EREE EP PEELE ELE TiEtl 
AINNSS Sebel ebereeraisiercts 
QRRARISIBISESSSRARRRFHRHSNWMVOSNOMLLL LY 
SS NS ~ y N“  S 
Fic. 1.—Diagram showing the precipitation at Williston, N. Dak.: Annual and average for the 40-year 
period from 1875 to 1914, inclusive (shaded columns); seasonal (April to July) for the 36-year period 
from 1879 to 1914, inclusive (solid black columns). 
rainfall for the growing season and the upper horizontal line the aver- 
age annual precipitation for the 36 years included in Table I. 
EVAPORATION. 
Table II shows the monthly precipitation and monthly evapora- 
tion during the growing season (April to July, inclusive) for the six 
years from 1909 to 1914, inclusive.. The evaporation as well as the 
precipitation is an important controlling factor on the growth of 
crops in the entire Great Plains area. The evaporation is determined 
from a free water surface, the method being the one generally in use 
where the Biophysical Laboratory of the Bureau of Plant Industry 
has been cooperating. | 
TaBLE I1.—Monthly precipitation and evaporation at the Williston substation for the 
growing season, 1909 to 1914, inclusive. 
[Data (in inches) from the records of the Biophysical Laboratory of the Bureau of Plant Industry.] 
Apr. May. June. July. Total. 
Year. 
Precipi-| Evapo- | Precipi-| Evapo- | Precipi-| Evapo- | Precipi-| Evapo- | Precipi- Evapo- 
tation. | ration. | tation. | ration. | tation. | ration. | tation. | ration. | tation. | ration. 
J 
Lt G/0 0) sR Seen anaes 0.64 | 3.000 2. 84 6. 466 3.72 | 95.173 2 GAOLS 8.90 | 20. 657 
LO) 5 eae eee 1.40 | 5.340 1.30 | 5.764 1.65 8.171 1.27 | 8.994 5.62 | 28. 269 
LEGIT Loe ee ie ea oe 32 | 95.790 3.00 | 6.087 todo je L45 1.40) 8.717 6.09 | 27.739 
TICS SL A7E psa Sa et teat Delay | anor 4.59 | 4.781 1.59 | 6.468 3.60 | 5.980} 11.91 21.104 
LSIUG eS ep age ee 15 4, 432 1.05 | 5.229 2.15 7. 676 2.60 | 7.154 5.95 | 24.491 
LOHGRS Ss Cees eae ae 49 | 3.866 ole ron O03 7.98 | 5.289 2.32 |. 7.162 | 12.00) 21.920 
Average....... 86 | 4.384 2.35 | 5.655 3.08 | 6.654 2.15 7.337 8.43 | 24.030 
1 Briggs, L. J., and Belz, J.O. Dry farming in relation to rainfall and evaporation. U.S. Dept. Agr., 
Bur. Plant Indus. Bul. 188, p. 16-20, 1910. 
