6 BULLETIN 297, U. S. DEPARTMENT OF AGRICULTURE. 
Fort Meade is only about 25 miles south of Newell, but the eleva- 
tion is 675 feet greater. Its proximity to the Black Hills apparently 
influences the rainfall to a considerable extent, as the annual precipita- 
tion is greater at Fort Meade than at Newell in those years for which 
the rainfall records of both are available. A comparison of Tables IT 
and III, however, will indicate to some extent the frequency with 
which conditions of precipitation similar to those prevailing from 1908 
to 1913 are to be expected. 
The mean annual rainfall at Fort Meade, as shown by Table ITI, is 
19.86 inches for the 33 years from 1881 to 1913. The maximum rain- 
fall for the period, 30.37 inches, was recorded in 1905. The minimum 
rainfall, 8.40 inches, was recorded in 1911. For practically all of this 
year, however, there are no records at Fort Meade, so that the rainfall 
at Vale, S. Dak., has been substituted. The rainfall at Vale is usually 
considerably lower than at Fort Meade, though the two points are 
only about 16 miles apart. The lowest annual rainfall actually re- 
- corded at Fort Meade is 13.25 inches, the record for 1885. 
The rainfall during the growing period for cereals (March to July) 
also shows a wide variation. The average seasonal rainfall for the 
33-year period is 13.45 inches. The maximum rainfall for the five 
months, 26.43 inches, was recorded in 1907; the minimum (except 
that of 1911 at Vale), 7.36 inches, was recorded in 1885. In the six 
years covered by the experiments at Newell the rainfall at Fort 
Meade during the growing season has exceeded the normal only in 
EGO’: ; 
EVAPORATION. 
The seasonal evaporation probably ranks next in importance to 
seasonal precipitation among the factors which influence the growth 
of crops at Newell. The daily evaporation has been recorded at the 
Belle Fourche Experiment Farm, and the total amount in inches by 
months from April to July is shown in Table IV. The record of 
evaporation was not kept for the month of March, but at Newell crops 
ordinarily make little growth during that month and hence this omis- 
sion is not of importance. The evaporation is determined from a 
free water surface, the method bemg that employed at all of the 
stations where the Biophysical Laboratory of the Bureau of Plant 
Industry has been cooperating.! 
The average evaporation for the four months from April to July, 
inclusive, for the six years from 1908 to 1913 was 27.620 inches. The 
lowest total evaporation, 23.627 inches, was recorded in 1909, the 
year of the greatest rainfall during the same months. The highest 
total evaporation, 33.906 inches, was recorded in 1911, the year of 
the lowest seasonal rainfall. Thus, the evaporation usually varies 
inversely with the precipitation, though this is not always the case. 
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. 
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