SPRING WHEAT IN THE GREAT PLAINS AREA. 5 
Or a succession of years may be either comparatively wet or com- 
paratively dry. 
The seasons of light rainfall are usually accompanied by other un- 
favorable conditions, such as higher wind velocity, higher tempera- 
ture, and lower humidity. The distribution of the rainfall is also very 
important in its influence on crop production. A crop may be pro- 
duced on a relatively small seasonal rainfall if it is well distributed. 
On the other hand, a season of higher rainfall, because of unfavorable 
distribution, may result in crop failure. 
Space in this bulletin will not permit the presentation of a com- 
plete record of the climatic conditions at the various stations during 
the time the work here reported was being done. It is, however, 
available in publications of the United States Weather Bureau. 
Table I gives the lowest, highest, and average annual and seasonal 
precipitation for the time covered by the work. The seasonal evap- 
oration is also shown. By seasonal is meant the precipitation or 
evaporation for the period between the average time of seeding and 
the average time of harvesting. No attempt is made to show other 
climatic factors, all of which are important. 
Table I. — Annual and seasonal precipitation and seasonal evaporation at fourteen 
stations in the Great Plains area} 
Station. 
Alti- 
tude 2 
(feet). 
Precipitation 3 (inches). 
Annual. 
Mini- 
mum. 
Maxi- 
mum. 
Aver- 
Seasonal. 
Mini- 
mum. 
Maxi- 
mum. 
Aver- 
Seasonal evaporation 3 
(inches). 
Mini- 
Maxi- 
mum. 
mum. 
19.117 
26. 273 
19. 820 
20.594 
21.104 
28. 269 
18.379 
27.366 
17. C64 
25.362 
20.111 
24. 248 
23.627 
33. 906 
24.698 
26. 647 
25.954 
35. 255 
25. 917 
32. 691 
29.390 
41.317 
33.315 
38. 926 
33.381 
41.002 
32. 305 
40. 704 
Aver- 
age. 
Judith Basin. . 
Huntley 
Williston 
Dickinson 
Edgeley 
Hettinger 
Belle Fourche. 
Scottsblufi.... 
North Platte.. 
Akron 
Hays 
Garden City... 
Dalhart 
Amarillo 
4,228 
3,000 
1,875 
2,543 
1,468 
2,253 
2,950 
3,950 
3,000 
4,600 
2,050 
2,900 
4,000 
3,676 
14.96 
11.92 
10.28 
11.93 
11.94 
12.72 
6.64 
13.77 
11.18 
14.51 
15.59 
11.82 
13.69 
10.69 
23.78 
11.92 
18.99 
21.22 
21.95 
15.68 
17.73 
18.51 
23.01 
22.46 
27.80 
23.58 
16.35 
27.80 
18.06 
11.92 
14.84 
16.69 
16.71 
14.20 
13. 11 
16.14 
18.05 
18.28 
21.30 
18.54 
15.11 
18.28 
6.50 
5.00 
5.62 
5.31 
5.08 
8.82 
1.92 
5.56 
4.38 
5.32 
3.87 
5.01 
4.54 
5.03 
10.90 
7.35 
12.00 
16.27 
15.73 
12.89 
12.75 
8.26 
11.25 
9.52 
12.87 
8.16 
14.86 
11.49 
8.62 
6.18 
8.31 
10.06 
9.60 
10.69 
6.82 
7.11 
7.77 
7.82 
9.55 
6.85 
8.17 
7.05 
21.330 
20. 207 
24. 705 
22.377 
20. 657 
22. 430 
27. 220 
25. 718 
30. 253 
28. 781 
32.628 
35.332 
38.596 
36. 709 
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 record of annual precipitation for 1914 is not included. The records of seasonal precipitation and 
evaporation for 1914 are mcluded for all stations, the evaporation being figured from Apr. 1 to July 31. 
The seasonal rainfall is the amount from Apr. 1 to July 31 for stations north of and including that at Belle 
Fourche. For stations south of Belle Fourche it is the amount between Mar. 1 and June 30. Evaporation 
measurements are made from a free water surface in a tank sunk into the soil to almost its full depth. The 
water surface is kept about level with the surface of the ground. 
GENERAL PLAN OF THE INVESTIGATIONS. 
Durum wheat has been used in these trials. The aim has been to 
use at each station the best standard variety available for general use. 
Changes are made only when necessitated by loss of seed or when 
