GRAIN-SORGHUM EXPERIMENTS IN THE PANHANDLE OF TEXAS. 15 
TEMPERATURE. 
The daily range in temperature is large, but not excessive. In 
general, the days in summer are warm to hot and the nights nearly 
always cool. Owing to the altitude (3,600 feet) the summer tem- 
_peratures are not as high as might be expected from the southern 
location. On the other hand, winter temperatures are not as low 
as might be expected from the elevation. 
The data on maximum, mean, and minimum temperatures and 
greatest daily range, by months, in the 10 years from 1907 to 1916, 
inclusive, are given in Table IV, which also contains data on precip- 
itation, the aspect of the sky, and the movement of the wind. 
The lowest recorded temperature in the period covered by these rec- 
ords was —11° F. on January 6, 1912, and the highest 105° F. on 
June 25, 1911. The average date of the last spring frost is April 
19 and that of the first fall frost October 30, leaving an average frost- 
free period of 194 days. 
EVAPORATION. 
The loss of moisture by evaporation in the Panhandle district is 
very great. The chief factors concerned are precipitation, wind, 
and temperature. The maximum evaporation naturally occurs, 
therefore, in periods of high temperatures and strong winds. 
Table V contains a comparison of monthly precipitation and 
evaporation records made at the Amarillo Cereal Field Station! during 
the six months from March to September in the 10-year period from 
1907 to 1916, inclusive. The evaporation measured is from the free 
water surface of a tank 8 feet in diameter. During this period, the 
evaporation was nearly four times as great as the precipitation 
during the same period. In 1909 a maximum of 0.69 of an inch was 
evaporated from this tank in 24 hours. These data show contrib- 
uting causes for certain crop results in various years. 
TaBLe V.— Monthly, seasonal, and 10-year monthly average precipitation and evapora- 
tion, in inches, at the Amarillo Cereal Field Station, during the six months from April 
to September, vnclusive, for the 10-year period from 1907 to 1916, inclusive. 
April. May. June. July. August. September. 8 eo 
Year. 3S oad et | er ae 
[ d | 
Prec. | Evap. | Prec.| Evap.| Prec.| Evap.| Prec.! Evap.| Prec.| Evap.| Prec.; Evap. Pree. Evap. 
| | 
1907. - - 1633 6.4 1 ead E 8.1 2.2 9.6°| 1:5 10.7 6.2 9.4 1.0 1.9°| 13-3 52.1 
1908. . 1.9 7.3 | 3.4 ORSe leeds el ON4e a 4G 8.1 | 3.4 8565) 915 6.8 | 16.5 50.5 
1909. - -3 Sra tee OO ioe o) ee OlS Te 2.261) S105 Ors 34 Wei} Wee) 8.4 | 12.8 56.5 
1910: =. -o 8.5° | 2.6 SSM leon et 200s eee sOninel 252 |poezno 8.8 sal 9.1] 9.8 58.6 
1911 3.9 HeAG Get) ALO 4s elon |e ong 7.5 | 2.5 8.9} 1.3 7.3 | 20:7 52.7 
1912 -8 TN alg 9.9} 2.3 OFOh |) 255) | 1059) 155 wea) |) Zoe) 6.5 | 11.0 52.9 
1913 id (hs (4 el LE 9.8} 2.3 (sj) Geet) PAZ Hone LOSS |peouo 5.9 | 13.2 53.4 
1914 3 De) Bs 6.7 5% 10.1 1.9 tein (|) 45 859) |e 8.0 | 11.3 49.1 
1915 4.8 4.6] 2.0 6.9} 1.2 Set) || Sha 7/ 9.3 | 4.6 (loa) Go) 6.0} 21.2 42.9 
1916 1.8 6.0 OMe ON sleet Ocudanin tbcran | bemel Leg ers 4 joe 1 Osan ier aa 7.7 | 12.2 56.6 
Av.| 1.8 cls ees 8.95) 2:1 | 9.9} 2.8} 10.2) 2.9 9.2] 2.2 Teh || SRO epi 
1 The precipitation and evaporation data given in Table V were obtained at the Amarillo Cereal Field 
Station in cooperation with the Office of Biophysical Investigations and the Office of Dry-Land Agriculture 
of the Bureau of Plant Industry, U.S. Department of Agriculture. 
