4 BULLETIN 218, IT. S. DEPARTMENT OF AGRICULTURE. 
Table I. — Annual and seasonal precipitation and seasonal evaporation at fourteen 
stations in the Great Plains area. 1 
Station. 
Alti- 
tude 2 
(feet). 
Precipitation :i (inches). 
Annual. 
Mini- 
mum. 
Maxi- 
mum. 
Aver- 
age. 
Seasonal. 
Mini- 
mum. 
Maxi- 
mum. 
Avcr- 
Seasonal evaporation 
(inches). 
Mini- 
Maxi- 
mum. 
mum. 
19.117 
26. 273 
19.820 
20. 594 
21. 104 
28. 269 
18.379 
27. 366 
17.664 
25. 362 
20. Ill 
24. 248 
23. 627 
33. 906 
24.698 
26.647 
25. 9-54 
35. 255 
25.917 
32. 691 
29. 390 
41.317 
33.315 
38. 926 
33. 381 
41.002 
32. 305 
40. 704 
Judith Basin.. 
Huntley 
Williston 
Dickinson 
Edgeley 
Hettinger 
Belle Fourche. 
ScottsblulT 
North Platte.. 
Akron 
Hays 
Garden City.. 
Dalhart 
Amarillo 
4,22S 
3,000 
1,875 
2,543 
1,46S 
2,253 
2,950 
3,950 
3,000 
4,600 
2, 050 
2,900 
4,000 
3,676 
14.96 
11.92 
10. 2S 
11.93 
11.94 
12. 72 
6^64 
13. 77 
11. IS 
14.51 
15.59 
11.82 
13.69 
10.69 
23. 7S 
11.92 
18. 99 
21.22 
2L95 
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. 11 
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 
i The years covered are the same as for the data shown in the other tables for the several stations. 
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 included for all stations, the evaporation being figured from Apr. 1 to July 31. 
The seasonal rainfall is the measurement 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. Evapo- 
ration 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. 
The same variety of oats is used on all plats at a station during any 
one year. The intention is to use the best variety that is available 
for general use. Changes are made only when seed breeding, selec- 
tion, or varietal testing makes available for general use a better 
variety. No attempt is made to use the same variety at different 
stations. The rate, time, and manner of seeding are the same for all 
plats at a station in any one year. As compared with more humid 
sections, the seeding is light, the usual rate being 6 pecks per acre. All 
seeding is done with a drill, rows being spaced from 6 to 8 inches apart, 
depending upon the locality. In different places different styles of 
drills are used. 
In the present study a table is presented for each station. The 
first part of such table shows the yields that have been obtained in 
each year by each of the different methods under which oats have been 
grown, considering only the variations in the one year preceding the 
crop. The previous crop whose stubble was treated as specified is also 
shown. Where more than one plat has been under the same treat- 
ment for the previous year, only the average yield of the whole number 
of plats so grown is given. Column 2 of the table shows the number 
of plats so averaged. The succeeding columns need no explanation, 
as they show the yields for each year as indicated and the averages of 
each method for the whole period of years. In the last column, where 
