12 BULLETIN 1387, U. S. DEPARTMENT OF AGRICULTURE 
The soil thermograph " torpedo" was placed horizontally on the sur- 
face of the soil beneath the 6 inches of water. The maximum and 
minimum air temperatures were taken daily under shade, but with 
a free circulation of air. Records were taken from May to Septem- 
ber, inclusive. 
The average maximum temperatures during 1923 and 1924 for the 
■five-month period from May to September, inclusive, were, respec- 
tively, 87.8° and 90.9° F. for the air and 79.6° and 78.5° F. for the 
water. The average minimum temperatures for the same five-month 
period were, respectively, 56.4° and 56.3° F. for the air and 60.6° and 
63.4° F. for the water. For the two-year period the average maxi- 
mum air temperature was 10 degrees higher than the average maxi- 
mum water temperature. But the average minimum air temperature 
was about 6 degrees lower than the average minimum water temper- 
ature. 
The average maximum air and water temperatures in 1923 and 
1924 for the months of May and June, during which time the rice 
was germinating and before it was large enough to shade the water 
effectively, were, respectively, as follows: For May, air 80.1° and - 
:°, water 82.7 and 84.7° F.; for June, air 83.5° and 90.0°, water 
85.0° and 87.9° F. The average minimum temperatures for the 
same months were, respectively, as follows: For May, air 50.9° and 
53.1°, water 53.7° and 61.0° F.; for June, air 54.0° and 57. 4°, water 
58.6° and 65.9° F. For the two-year period the average maximum 
air and water temperatures for May and June were about equal, but 
the average minimum temperature for the same months was about 
(> degrees higher for the water than for the air. 
Each year during July, August, and September the water was 
almost completely shaded by the rice crop, and the average maxi- 
mum air temperature for each month was higher than the average 
maximum water temperature. However, the average minimum 
water temperature for each month has ranged from 1.5 to 7.7 degrees 
higher than the average minimum air temperature. 
The temperature readings in 1923 and 1924 indicate that water 
to a depth of 6 inches maintains a higher and more uniform tempera- 
ture than the air during the period of germination and early growth. 
During July, August, and September, when the water is shaded by the 
rice crop, the mean air temperatures are higher than the mean water 
temperatures. This indicates that, in so far as temperature alone 
is concerned, conditions are more favorable for germination under 
inches of water than they are in the atmosphere or than they are 
presumably at the surface of the soil. 
EXPERIMENTS ON SUBMERGENCE IMMEDIATELY AFTER THE RICE HAS EMERGED 
BROADCASTING AND DRILLING SEED COMPARED 
Experiments to compare broadcasting and drilling were conducted 
during 1922, 1923, and 1924 on land that had been sown to rice and 
fallowed in the cultural experiments in alternate years from 1914 to 
1921. In 1921 the land was fallowed. The 1922 crop was the fifth 
rice crop on this land in 9 years, the 1923 crop was the sixth rice 
crop in 10 years, and the 1924 crop was the seventh rice crop in 11 
years. In the spring of 1922 the fallow land was double disked and 
