460 
Journal of Agricultural Research 
Vol. XIV, No. XI 
single value for each field—the average of all the determinations on the 
samples from that field—as in each field the differencess between the 
various samples were less than the experimental error. The samples 
were composites of sections from 12 cores taken 5 to 10 feet apart with a 
1.5-inch soil tube. 
At the time of the first sampling, the soil of the bluegrass field was 
already dry, showing a ratio of only 1.3 to 1.5 During the following 
three weeks it became steadily drier until, on April 30, the ratio had 
fallen to 1.1. The rains following this raised it to an average of 3.4. 
Throughout the dry period the soil in the alfalfa field was distinctly 
moister than that in the grass field, but here also it became steadily drier 
until the May rains raised the ratio to an average of 3.5. 
BLUE GRASS HELP | FALL PLOWCOFIEtO j ALFALFA, FIELD 
Ocpth ■ 1. On April 9,-* after 2 months of rainless weather 
,NCH - ~ " 10 20 30 40% I ' io 56 30 40% I 7- "" to" 20 SO + 0 % 
3. On April 30, 0.04-inch cf rain during the preceding 2 weefcs. 
--t-EGENIO- 
Hygroscopic water. 
Free wafer not in form of growth water. 
Growth .water, also to be included in free water. 
H. C.-Hygroscopic coefficient 
W. G-Wilting coefficient* 
M. £.-Moisture equivalent. 
FiG. 3.—Diagram showing moisture conditions in the surface 6 inches of soil in three adjacent fields at 
the Nebraska Agricultural Experiment Station during and just at the close of the record-breaking 
drouth in the spring of 1910. The total precipitation betweeen December 4, 1909, and May 1,1910, was 
as follows; December 5 to 31, 0.44 inch; January, 0.88 inch; February, 0.09 inch; March, 0.08 inch; and 
April, 0.05 inch. 
In the fall-plowed field the moisture in the surface inch was already at 
the minimum on the occasion of the first sampling, the ratio being only 
0.4. During the following week of dry weather it did not change appre¬ 
ciably, but during the next 12 days the average ratio in the 3-to-6-inch 
section fell to 2.2. Even then the moisture conditions below the first 
inch were favorable for plant growth. The May rains raised the ratio to 
an average of 3.2. 
While the loss of moisture in the fall-plowed field was due entirely to 
evaporation, the uniform loss in moisture in the sections below the 
