June 26, 1916 Water Requirement of Corn and Sorghum 



483 



SUMMARY 



The water requirement was determined for four varieties of com and 

 two varieties of sorghum in 1914 and for three varieties of com and five 

 varieties of sorghum in 191 5. 



The plants were grown in large sealed galvanized-iron cans which 

 contained approximately 1 10 kgm. of soil. The soil had a wilting coeffi- 

 cient of 13, and under the conditions of the experiment it had a moisture 

 content of 20 to 21 per cent (dry basis). This moisture content was 

 kept approximately constant by replacing every 48 hours the water that 

 had been lost by transpiration. 



Three plants of com were grown in each can during both seasons. 

 Six sorghum plants were grown to each can in 1914, but in 191 5 the 

 number of plants was reduced to three plants to a can. 



The plants were grown in a screened inclosure in order to protect them 

 from the hailstorms and severe winds that are prevalent in western 

 Kansas. The rate of evaporation in such a shelter was found to be only 

 two-thirds as high as under field conditions. 



The season of 191 5 was cooler and more humid, and the rate of evapora- 

 tion much lower than in 191 4. As a consequence the water requirement 

 of the former year was only about 66 per cent of that of the latter year. 

 A summary of the water requirement for the two seasons is given in 

 Table VII. 



Table VII. — Summary of tJie water requirement of the varieties of corn and sorghum 

 grown at Garden City, Kans., in IQ14 and igi^ 



Plant and period of growth. 



1914. 



Corn: 



Pride of Saline, May 26 to August 



Sherrods White Dent, May 26 to 



August 22 



Hybrid F3 H58, May 26 to August 



22 



Chinese, May 26 to August 22 



Kafir : 



BlackhuU, May 26 to September 3 

 MiLO: 



Dwarf, May 26 to August 22 



1915- 

 Corn: 



Pride of Saline, May 22 to August 



25 



Sherrods White Dent, May 22 to 



August 18 



Hybrid F4 Hjg, May 22 to August 



25 



Water requirement based on — 



Dry matter, 



including 



roots. 



365±i5 



305 ± 6 

 3i9± 5 



236± 3 



Dry matter, 



excluding 



roots. 



403 ±18 

 396±l6 



355± 8 

 4i8± 7 



32S± 7 

 340 ± 5 



267± 2 

 299 ± 8 

 246 ± 6 



Grain. 



i.iySdb 45 

 I, 022 ±100 



Stem and 

 leaves. 



403 ±18 



396±i6 



355± 8 

 4i8± 7 



45i± 7 

 53o±i5 



267 ± 2 

 299 ± 8 

 246 ± 6 



