8 



Journal of Agricultural Research 



Vol. HI, No. I 



The marked response of the plants to the different seasons is shown in 

 the reduced water requirement in 1912. (See Tables XXXII, pp. 36-38, 

 and XXXIII, p. 39.) 



WATER REQUIREMENT OF VARIOUS CROPS 

 WHEAT 



The water requirement of six varieties of wheat, including emmer, 

 was measured at Akron in 191 2. The results a'rranged in order of 

 increasing water requirement based on dry matter are as follows : 



Variety of wheat Water requirement 



Turkey 364±6 



Kharkov 365±6 



Kubanka 394±7 



Emmer 428±3 



Bluesteni 451 i4 



Spring Ghirka 4S7±3 



c/d/AZ" 



<yuLy 



^uff. 



vsvr/^r. 



Fig. I. — Evaporation from a free-water surface (tank) at Akron. Colo., in 1911 and 1912. Note the 

 marked reduction in evaporation in 1912 after June 10. A volcanic eruption in Alaska occurred on 

 June 6. 



The Turkey and Kharkov varieties (PI. Ill, fig. 6) were tested for 

 the first time in 191 2. These are winter varieties and were transplanted 

 to the pots in the spring from field plats sown in the fall. They gave 

 the same water requirement and appear to be about 10 per cent more 

 efficient than the Kubanka (PI. Ill, fig. i), which has heretofore been 

 the most efficient wheat tested as regards economy in the use of water. 

 This comparison, however, ignores the small quantity of dry matter in 



