oct. 23,1916 Daily Transpiration during Normal Growth Period 
199 
RELATIVE DAILY TRANSPIRATION OF DIFFERENT CROPS 
In the preceding discussion the transpiration-evaporation ratio has * 
been used in order to eliminate, so far as possible, the daily fluctuations 
Fig. 13.— Graph showing a linear relation between the logarithm of the transpiration-evaporation ratio 
of Northwestern Dent corn and the time. 
in transpiration due to changes in weather. The relative march of the 
transpiration of any two crops can, however, be determined directly 
Fig. 14.—Graph showing a linear relation between the logarithm of the transpiration-evaporation ratio 
of Minnesota Amber sorghum and the time. 
by comparing the transpiration day by day; in other words, if two crops 
are grown simultaneously and have approximately the same length of 
growing season, the relative change in transpiration may be obtained by 
