THE DRY FARMING CONGRESS. loU 



EVAPORATION '08 



r^?si 



1 !S! APR, 



MAY 



JUNE 



JULY 



AUG. 



SEPT. 





s 



EDGELEY ^ 

 NORTH DAK- * 



1 





4.1 



6.2 



7.0 



6.4 



5.6 



2&2 























- 







- 





























h 



r 





r 



















3 



NORTH PLATTE- 



NEa p 



6.5 



6.8 



6.3 



7.6 



6.9 





&2 





42.2 



































































H 

































AMARILLO |o 

 TEX. 1 





7.2 





9.1 







3 4 





ai 





6.8 



50.2 







































1 







































1 







































Fig. 2. 



Plains. The evaporation for the six summer months at Edgeley was 

 about 30 inches, at North Platte about 42 inches, and at Amarillo about 

 50 inches. For the same rainfall, then, the conditions at the southern 

 stations would be much more severe than at the northern stations, owing 

 to the increased rate of evaporation. 



Soil Moisture Determinations. 



'"The real criterion of the resultant of the rainfall and the various 

 factors which tend to dissipate it, is found in the moisture content of the 

 soil. The accompanying charts (Figs. 5-6) show the results of a series of 

 soil moisture determinations for the years 1907 and 1908, made at the 

 co-operative stations in the Great Plains. The determinations at Edgeley, 

 North Dakota, were made by Mr. E. C. Chilcott. and at North Platte, 

 Nebraska, by Mr. W. W. Burr. 



"These charts show the changes taking place in the soil moisture 

 during the growth of the crops on the co-operative experimental plots 

 of the Office of Dn.' Land Agriculture of the Department. The lines on 

 the chart show the changes in the moisture content during the growing 

 season for four plots treated in different ways. The yields given for the 

 different plots were furnished by the Office of Dry Land Agriculture. 



"In each case 'A' was spring plowed. 'B' was fall plowed, 'C was 

 fallow in 1907, and 'D' was fallow in 1906 and 1908. 



Moisture Determinations in Wheat. 



"Referring first to the diagram No. 5, from Edgeley. North Dakota, 

 showing the soil moisture determinations made in connection with 

 wheat, it will be noted that the *D' plot, which was fallowed on the pre- 

 vious year, starts off with a larger amount of moisture than either the 



