Rice Production in Southwestern Louisiana 
25 
The loss of water from tank B is assumed to represent the loss of 
water by evaporation from a rice field during submergence. The 
data presented indicate that the actual evaporation from a rice field 
in July, August, and September varies but little from month to 
month, on account of the uniform conditions produced by the shade 
of the rice plants. 
The loss of water from tank C represents evaporation from a body 
of water shaded by rice plants and also transpiration by the plants. 
The loss from tank C minus the loss from tank B is assumed to 
represent the loss of water by transpiration. The data given in 
Table 16 indicate that the average daily loss of water by transpira- 
tion is greatest in August and September. The total loss of water 
from the rice plats during submergence minus evaporation and trans- 
piration based on the data from tank C is assumed to represent the 
loss of water by seepage. In Table 17 are given data assumed to 
represent the average daily loss of water by evaporation and by 
transpiration from a rice field during the 3-month irrigation period 
of each year from 1910 to 1917, inclusive. The average daily loss 
of water by seepage and by assumed evaporation and transpiration 
from plats in the depth-of-submergence experiments for the 3-month 
period for 1917, 1918, and 1919 are given in Table 18. 
Table 17. — Average daily loss of water by evaporation and transpiration from 
tanks B and C at the Rice Experiment Station, Crowley, La., for July, 
August, and September of each year from 1910 to 1917, inclusive 
[Data in inches] 
Loss of water 
1910 
1911 
1912 
1913 
1914 
1915 
1916 
1917 
Aver- 
age 
Total by evaporation and transpira- 
0.272 
.106 
.166 
0.259 
.094 
.165 
0.373 
.094 
.279 
0.236 
.099 
.137 
0.264 
.116 
.148 
0.267 
.132 
.135 
0.373 
.110 
.263 
0.251 
.117 
.134 
0.287 
.109 
B y transpiration from tank C 
.178 
Table 18. — Average daily loss of tcater by seepage and evaporation and tran- 
spiration from plats in the depth-of-submergence experiments at the Rice 
Experiment Station, Crowley, La., for July, August, and September for 1917, 
1918, and 1919 
[Data in inches] 
Loss of water 
Depth of submergence (inches) 
2 
4 
6 
8 
Total 
0.316 
.271 
.045 
0.295 
.271 
.024 
0.280 
.271 
.009 
0.438 
By evaporation and transpiration * 
By seepage. ._ . . . . ... 
inches.. 
do___.. 
.271 
.167 
1 Average daily loss of water from tank C for the 3-month period for 1917, 1918, and 1919. (See Table 16.) 
Daily seepage from the different plats varied in these experiments 
from 0.009 to 0.167 inch. Theoretically, seepage should be propor- 
tional to depth of submergence. The data of Table 18 agree with 
this theory only in the loss of water by seepage from the plat sub- 
merged 8 inches. In these experiments it was not possible to use the 
broad levees ordinarily used in field practice, and the high narrow 
levees cracked to a greater or less extent in drying. Because of 
variations in cracking, the losses from the plats submerged 2, 4, 
and 6 inches show no relation to the depth factor. The elements 
