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BULLETIN 1340, U. S. DEPARTMENT OF AGRICULTURE 
transpired by the sugar beets during their period of growth, as de- 
termined by the mean results of three tank experiments. The mois- 
ture content in each tank was maintained as nearly as practicable 
at IT per cent of the dry weight of soil, by adding water at each 
semiweekly weighing to make up the loss due to transpiration and 
evaporation. The loss due to evaporation from the soil in each tank 
was afterwards deducted. The mean temperature of the air, evapo- 
Fig. 14. — Amount of water transpired by sugar beets between seed and harvest as 
determined at Denver, Colo., in 1919. Modifying meteorology also shown. 
Stepped lines indicate mean values for several days 
ration from a water surface, and wind movement during the period 
of growth are also given. 
It will be noted that the quantity of water transpired is small 
from the time the sugar beets are sprouted on May 23 until they are 
4y 2 inches high on June 20. From this stage the transpiration in- 
creases quite rapidly and uniformly until August 4, when the beets 
are 18 inches high. From the middle of August until October 7, 
