26 



DEY FARMING IN RELATION TO RAINFALL AND EVAPOEATION. 



work cover experiments at eleven stations, extending from Montana 

 to the Panhandle of Texas. 



Table III. — Variation in yield of spring-sown wheat with rainfall in the Great Plains. 

 [Based upon the field experiments of the Office of Dry-Land Agriculture Investigations.] 



Station and year. 



Ordi- 

 nary 

 meth- 

 ods. 



Conser- 

 vation 

 meth- 

 ods. 



Sum- 

 mer til- 

 lage. 



Rota- 

 tions, 

 average 

 of 7 

 plats. 



Aver- 

 age 

 yield 

 of 10 

 plats. 



Rain- 

 fall, 

 April- 

 July, 

 inclu- 

 sive. 



. l 

 Rain- 

 fall 

 for the 

 year. 



Judith Basin, 



Bush. 



Bush. 



Bush. 



Bush. 



Bush. 



In. 



In'. 



Mont. , 1909 



33.0 



33.4 



34.0 



34.6 



34.3 



14.0 



25.6 



D ic kin son, N. 

















Dak.: 

















1908 



24.3 



17.7 



33.8 



28.1 



27.3 



10.5 



19.5 



1909 



26.8 



25.2 



35.7 



36.4 



34.3 



11.2 



20.9 



Edgelev,N.Dak.: 

















1907 



4.1 



7.0 



9.9 



11.1 



9.9 



6.7 



11.5 



1908 



13.3 



15.3 



16.0 



17.1 



16.4 



9.2 



17.1 



1909 



28.3 



23.3 



27.0 



29.7 



28.7 



10.8 



15.6 



Highmore , S. 

















Dak.: 

















1907 



28.8 



29.7 



30.0 



28.2 



28.6 



11.1 



17.3 



1908 



26. 3 



19. 7 



30. 7 



25. 3 



25. 4 



12. 5 



22. 4 



Beliefourche, S. 

















Dak., 1909 



23.8 



23.3 



32.2 



29.1 



28.3 



7.9 



(«) 



North Platte, 















Nebr.: 

















1907 



24.5 



26.0 



31.8 



23.7 



24.8 



12.3 



19.1 



1908 



22.7 



27.3 



40.5 



28.9 



29.3 



12.8 



20.0 



1909 



23.0 



15.3 



18.0 



20.1 



19.7 



13.7 



18.9 



Akron, Colo.. 1909. 



14.3 



10.3 



18.5 



17.0 



16.2 



10.2 



22.4 



Hays, Kans., 1908. 



1.2 



4.5 



4.2 



3.8 



3.7 



14.2 



25.3 



Garden City, 

















Kans., 1909 



2.1 



3.2 



6.7 



3.0 



3.3 



11.3 



22. C 



Dalhart, Tex., 

















1909 



.0 



.0 



10.5 



1.1 



1.8 



8.3 



16.0 



Amarillo, Tex.: 

















1908 



17.0 



14.0 



16.0 



10.5 



12.1 



12.6 



19.1 



1909 



. -0 



2.8 



10.5 



1.4 



2.3 



8.5 



18.4 



Rainfall for 

 the year. 



Above 

 nor- 

 mal. 



In. 

 10.4 



4.5 

 5.9 



Be- 

 low 

 nor- 

 mal. 



In. 



8.0 

 2.5 

 4.1 



5.0 



Rainfall for 

 the season. 



Above 

 - nor- 

 mal 



1.0 

 1.1 



3.3 

 1.9 



3.3 



Be- 

 low 

 nor- 

 mal. 



In. 



4.8 

 2.3 

 .7 



a Year not complete. 



The first column of the table shows the station and State in which 

 the field work was conducted and the year in which the experiments 

 were carried on; the second column gives the yield of spring wheat 

 in bushels per acre under ordinary methods of cultivation — that is, 

 shallow spring plowing and no harrowing of the grain after planting; 

 the third column, headed " Conservation methods," gives the yields 

 of spring wheat on land plowed 8 inches deep in the fall, put in good 

 tilth in the spring before planting, and harrowed after the grain was 

 up in order to conserve moisture; the fourth column, headed " Sum- 

 mer tillage," gives the yield of spring wheat grown on land summer 

 tilled the preceding year; the fifth .column, headed " Rotations," 

 gives the average yield of wheat in seven different rotations carried 

 on at each of the stations; all of the methods employed and the yields 

 obtained are described in detail in the bulletin referred to. In the 

 sixth column is given the average yield of wheat from the ten plats 

 previously considered, namely, the seven rotation plats and three 



188 



