Dec. 4, 1916 
Evaporation of Moisture from the Soil 
45i 
Table V shows the average temperature for morning, noon, and after¬ 
noon. It is worth noting that the shade caused a reduction in tempera¬ 
ture, complete shade causing a greater reduction than part shade. 
Tabl© V .—Effect of shading on temperature and evaporation; temperature (°C) average 
for 13 days 
Treatment. 
Time. 
Aver¬ 
age. 
Evapora¬ 
tion loss. 
Morn¬ 
ing. 
Noon. 
Even¬ 
ing. 
Sunshine. 
3°. 2 
25. 6 
19.7 
41-3 
32. 2 
23. 2 
34.2 
28. 7 
24. 6 
35 -2 
28.8 
22. 5 
Gw. 
554-8 
513-4 
407.8 
Half shade (cheesecloth). 
Shade (wood). 
Table V shows the total loss in grams for each treatment. Figure 7 shows 
by graph the average temperature and the total loss with sunshine for 
part and for complete 
shade. It is notice¬ 
able that the evapo¬ 
ration losses decrease 
as shade increases. 
TEMPERATURE 
Temperature, rela¬ 
tive humidity, and 
initial quantity of mois¬ 
ture are usually con¬ 
sidered to be the most 
important factors in 
determining the in¬ 
tensity of evaporation. 
Perhaps temperature 
is most active. Fortier 
(5) shows that a reduc¬ 
tion from 88° to 53 0 F. 
causes a corresponding 
reduction in evapora¬ 
tion loss of 85 per cent. 
These figures suggest 
Fig. 7.—Loss'of water from soil and temperatures in the sun and 
under cheesecloth and board shade. 
the close relationship of evaporation to temperature. This important 
effect of temperature was made clear in a number of experiments where 
other factors were being studied. 
To get some specific effects of temperature on the rate of evaporation 
of moisture from the soil, a number of large water baths were so arranged 
