CROP PRODUCTION IN" THE GEEAT PLAINS AREA. 6 



tions of the Bureau of Plant Industry. The entire scientific staff of 

 the Office of Dry-Land Agriculture, numbering about 30 men, has 

 participated hi the details of the field work and the preparation of 

 the data for publication. The investigations have also had the benefit 

 • of the counsel and advice of the scientists connected with the various 

 cooperating offices and State agricultural experiment stations. 



CLIMATIC FEATURES OF THE GREAT PLAINS. 



The climate of the Great Plains has been classified as semiarid. It 

 may be better to say that it is variable. One season may have almost 

 humid and another almost arid conditions. The mean annual pre- 

 cipitation is relatively low. Years of relatively high precipitation 

 may be followed by years of relatively low precipitation. Other 

 climatic factors usually correspond with the rainfall. In a year of 

 relatively high rainfall there will be a lower rate of evaporation and 

 higher humidity than in a year of low rainfall. 



Another climatic factor of much importance in crop production 

 on the Plains is the distribution of the rainfall. This is probably 

 more important in crop production than the amount of annual rain- 

 fall. A relatively low rainfall, properly distributed, may produce 

 a crop where a much higher rainfall, unfavorably distributed, may 

 accompany a crop failure. 



Table I. 



Annual and seasonal precipitation and seasonal evaporation at fourteen 

 stations in the Great Plains area. 1 



Station. 



J udith Basin. . . 



Huntley 



Willi -ton 



on 



Edgeley 



Hettinger 



Belle Fourche. . 



ilufl 



North Platte... 



Akron 



il 



Qarden City.. . 



Dalbart 



Ar/nrillo 



Alti- 

 tude 



(feet) 2 



Precipitation (inches) 3 . 



Annual. 



Seasonal. 



Mini- 

 mum. 



14. 96 

 11.92 

 10. 25 

 11.93 

 11.94 

 12.72 

 6.64 

 13.77 

 11.18 

 14.61 

 15.69 

 LI. 82 

 13.69 

 10. 69 



Maxi- 

 mum. 



23. 78 

 11.92 

 18.99 

 21.22 

 21.95 

 16.68 

 17.7:; 

 18.51 

 23.01 

 22. 46 

 27. 80 

 2:;. ns 

 16.35 

 27.80 



Aver- 

 age. 



18. 00 

 11.92 

 14.84 



10.09 

 10.71 

 I I I'll 

 13.11 

 10.14 

 IS. 0.") 



18. 28 

 21.30 

 18.54 



15. il 



is. -s 



Mini- 

 mum. 



7.04 

 5.92 

 4. 75 

 6. 85 

 7.85 

 8.92 

 4.08 

 2.53 

 f>. S5 

 6. 42 

 8. is 

 2.79 

 5. 09 

 0.17 



Maxi- 

 mum. 



17.21 

 6.02 

 14.49 

 16.28 

 14.98 

 12.47 

 9.78 

 8.52 

 12. 00 



13. 86 

 17. 97 



14. 43 

 9. 85 



11.38 



Aver- 

 age. 



9.34 

 5.97 

 9.66 

 9.79 

 10.11 

 10.36 

 6.90 

 4.69 

 9.45 

 9.02 

 11.17 

 8.65 

 8.01 

 ". 13 



Seasonal evaporation. 3 



Mini- 

 mum. 



22.012 

 23. 754 

 20. 422 



20. 673 

 18. 663 



21. 539 

 26. 472 

 23. 804 

 28. 445 

 20. 004 

 30. 025 



34. 325 



35. 459 

 33. 804 



Maxi- 

 mum. 



29.353 



24. 214 

 20. 877 



25. 745 

 24. 893 

 28. 239 

 33. 750 

 29. 381 

 38. 168 

 35. 054 



41. 373 

 43. 510 

 41.748 



42. 070 



Aver- 

 age. 



24. 491 

 23. 984 

 24. 216 

 23. 919 

 21. 866 

 24. 039 

 28. 794 

 20. 081 

 32. 359 

 31.420 



35. 790 



38 185 



38. 9ss 



36. 724 



i Tin- ye si covered are the same ae for i be data shown in the tables for the several stations. 



i The altitude given Is fir the odd when' the work was done and is based In most cases on that of the 



town. 

 • The records of annual precipitation for 1914 are not included. The records of seasonal precipitation 



and evaporation for 1914 are Included toi all Btations, being figured from May I to Sept. i. Evaporation 

 i made from a free water Burface, In a tank sunk Into i be soil to almost Its full depl b. The 

 rfacelskepl about level with the surface of the ground. 



