rr” 
LYSIMETER EXPERIMENTs —II 59 
TABLE 9. Evapro-TRANsPIRATION FoR ALL Crops RAISED DURING FIvE-YEARS PERIOD 
| 
| 
Liters 
; per tank 
2 pieafinlll (arming ain DE ce ea ra a 1,388 .7 
Percolation from planted tanks (average annual)..................2....--- 848 .7 
Transpiration and evaporation from planted tanks........................ 540.0 
; Phy ApOxtlANs Diba tlONELAa tO sors c45 sects Acids ats ee cs iaidiare ele Srsbi@ eaclebs sie ote Sela 1:908 
Neither the minimum transpiration ratio nor the evapo-transpiration 
tatlo is necessarily the same as the actual transpiration ratio. The former 
is likely to be less because the evaporation from the unplanted soil is almost 
always greater than the evaporation from the planted soil, and the latter 
is almost sure to be greater because it includes the water that evaporates 
from the surface of the soil as well as that which is transpired by the 
plants. The actual transpiration ratio therefore lies between 1:451 and 
1:908. 
It is significant that both transpiration ratios for the Volusia soil are 
so much wider than those for the Dunkirk soil, the former being about 
56 per cent wider than the latter in both cases. It seems fair to assume 
that the actual transpiration ratio is correspondingly wider for the Volusia 
soil. Such differences cannot be attributed to conditions other than the 
soil, and probably arise from a difference in the concentration of the soil 
solution. The transpiration ratios are inversely proportional to the con- 
centration of the drainage water and the crop yields from these two soils, 
as may be seen in table 10, the data in which are for the five-years periods 
already reported with the exception of the crop yields, which are for 1915, 
1916, and 1917 only, since those were the only years in which the same crops 
were grown on both sets of tanks. 
