4 BULLETIN 218, IT. S. DEPARTMENT OP 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 :l (inches). 



Annual. 



Mini- 

 mum. 



Maxi- 

 mum. 



Seasonal. 



Mini- 

 mum. 



Maxi- 

 mum. 



Avor- 



Seasonal evaporation 3 

 (inches). 



Mini- 

 mum. 



M axi- 

 mum. 



Aver- 

 age. 



Judith Basin. 



Huntley 



Williston 



Dickinson 



Edgeley 



Hettinger 



Belle Fourche 

 Scottsbluff... 

 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 



19.117 

 19. 820 

 21. 104 

 18. 379 

 17. 664 

 20. Ill 

 23. 627 

 24. 698 

 25. 954 

 25.917 

 29. 390 

 33. 315 

 33. 381 

 32. 305 



26. 273 

 20. 594 

 28. 269 

 27. 366 

 25. 362 

 24. 248 

 33.906 

 26. 647 

 35. 255 

 32. 691 

 41.317 

 38. 926 

 41.002 

 40. 704 



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. » 



s 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. ForstationssouthofBelleFourcheit is the amount betweenMar.l and June30. 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 



