80 
WATER REQUIREMENT OF PLANTS. 
The cold-weather crops have a higher average water requirement 
than the monsoon crops. Barley and oats have the same water 
requirement, while wheat is about 16 per cent 
higher. Chick-peas, rice, and linseed have 
the highest water requirement, which is nearly 
four times that of the lowest, sugar cane. 
Next in efficiency to the sugar cane are millet, 
corn, and sorghum. 
BRIGGS AND SHANTZ's EXPERIMENTS. 
The writers (1913) have measured the water 
requirement of plants in the Great Plains at 
Akron, Colo., and at Dalhart and Amarillo, 
Tex. For a comparison of the results at 
Akron and the Texas stations the reader is 
referred to Table LI 
(p. 61). 
The plants were 
grown in large galvan- 
ized-iron cans contain- 
ing about 115 kilograms of soil. All direct 
evaporation from the soil was practically elimi- 
nated by tight covers and by sealing the open- 
ings around the stems of the plants with wax 
(fig. 5). The method of watering is shown in 
figure 6. In order to determine the probable 
error of the results, six pots were used in each 
determination. Over 200 cans were employed 
in the experiments at Akron in 1911, including 
tests with 30 varieties of crop plants. The results are summarized 
in Table LXXI. 
285 
Fig. 5.— Pot used by Briggs and 
Shantz (1913) in measuring the 
water requirement ot plants. 
Fig. 6. 
device used by Briggs and 
Shantz (1913) in adding 
water to the pots. 
