WINTER WHBEAT IN THE GREAT PLAINS AREA. a 
tions throughout the area. There is, however, a wide range of soil, 
climatic conditions, and altitude. The lowest station where winter 
wheat is grown is Hays, Kans., with an altitude of 2,050 feet, and 
the highest is Archer, Wyo., with an altitude of 6,012 feet. The 
length of the growing season for winter wheat is naturally much the 
same throughout the area, but there is a variation of approximately 
a month to six weeks in the respective dates of seeding and harvest- 
ing. The northern stations seed somewhat earlier than the southern, 
while the southern stations harvest earlier than the northern. 
CLIMATIC CONDITIONS. 
The Great Plains area is characterized by a varying amount of 
annual and seasonal precipitation, with very uncertain distribution. 
Years of relatively high precipitation with favorable distribution may 
be followed by years of relatively low precipitation with very unfavor- 
able distribution. It may besaid that the uncertainty of the distribu- 
tion rather than the total amount of rainfall received is the factor that 
makes crop production hazardous. In connection with this work, 
complete climatic data have been obtamed. It is not practicable, 
however, to present them in this publication. Table I shows the min- 
imum, maximum, and average annual and seasonal rainfall and thesea- 
sonal evaporation at each station for the years for which the yields are 
here reported. By seasonal is meant the precipitation or evaporation 
for the period between the average time of growth beginning in the 
spring and the average time of harvesting. Noattemptis made here to 
show any of the other climatic factors or the amount of water already 
in the soil at seeding time, any of which might have an important in- 
fluence on yields. The annual precipitation as here given is not the 
average as determined from the complete record, but is the average 
annual precipitation of the years whose results are under study 
Taste I— Annual and seasonal precipitation and seasonal evaporation at thirteen sta- 
tions in the Great Plains area.} 
PRSGIOMD AU)” AEGEGS tee evaporation 4 
Alti- (inches). 
Station. Fade Annual. Seasonal. 
eet) Mini- | Maxi-| Aver- | Mini- | Maxi-| Aver-| Mini- | Maxi- | Aver- 
mum.|mum.} age. |mMum.|mum.| age. | mum. | mum. | age. 
SudithiBasing.222.228 A 4,228 | 14.96 | 23.78 | 18.31 | 6.50] 11.06] 9.03 | 18.544 | 26.273 | 21.205 
1S [GIES 8 ey Et aS apa ae 3,000 |} 11.92 | 17.54 | 13.79 | 5.00 | 11.83 7. 62 | 18. 486 | 21. 799 | 20.175 
Belle Fourche..........-.-- 2, 950 6. 64 | 21.02 | 13.96 1.92 | 15.38 &. 04 | 18.388 | 33.906 | 25. 415 
PNEOMMOTOL Ss cee nase ess. 3,507 | 13. 23 | 30.41 | 17.66 |} 6.93 | 20.34 | 11.14 | 19.555 | 28.140 | 24. 828 
neher TPA 3 bo. 6,012 | 11.77 | 18.32 | 14.16} 4.64/| 10.16] 7.12} 20.056 | 27.320 | 24.319 
DCOLISDIUN oo. ha sacs a aes 3,950 | 9.95 | 23.58 | 15.44 | 6.75 | 10.78] 8.31 | 23.006 | 27.620 | 25.556 
North Platte. sii 22552: 4. = 3,000 | 11.18 | 34.85] 19.31 | 5.61 | 23.52 | 11.09 | 24.621 | 35.255 | 29.620 
(0) 1S REE Rea , 60 13 74 4 25.00 | 18.22} 6.60 | 14.17} 9.67 | 21.796 | 33.114 | 28. 449 
BY Sae ries seek ee de de ks 2,050 | 15.59 | 32.90 | 21.45] 3.87 | 16.58 | 10.41 | 22. 402 | 41.317 | 31.333 
Gardeni@iby.. 220.222). = 2,900 | 9.70 | 26.51 | 18.05} 5.01 | 10.95] 7.51 | 29.802 | 39.354 | 35.144 
Dalhangee week. GF. LAL ios 4,000 | 13.69 | 22.81 | 16.67) 4.54 | 14.86) 8.21 | 31.854 | 41.002 | 37.813 
ASTETHU GS See Rgenee a aera 3,676 | 10.69 | 27.80} 18.61] 5.03 | 11.49] 7.11 647 | 40. 704 | 36.130 
Mreameari. be 2 As 4,194 | 10.89 | 22.24 | 17.12] 2.83) 11.07] 7.03 | 32.285 | 42.405 | 37.139 
1 The years covered are the same as for the data shown in the other tables for each station. 
2 The altitude given is for the field where the work was done and is based in most cases on that of the 
nearest town. 
3 The seasonal rainfall is the amount from Apr. 1 to July 31 for stations north of and including Akron. 
For stations south of Akron it is the amount between Mar. 1 and June 30. 
4 The evaporation is figured from April 1 to July 31. 
