sept. 9 ,1918 Variations in Moisture Content of a Loess Soil 
46s 
use was made of a small part of field M, in which bluegrass had almost 
entirely crowded out the alfalfa sown in 1907. Previous to that year 
the field for almost 40 years had been in annual crops. However, the 
moisture data indicate that the change caused no serious break in con¬ 
tinuity, as on August 3 the moisture conditions in field M were very 
similar to those in J on July 29, except for the losses from the surface 
few inches during the interval. 
As a representative area of both fallow and com land we employed 
a field lying between fields J and M and referred to below as C-F. After 
a long period in bluegrass it had been plowed a few years before. In 
1911 it was in corn, and after the removal of the crop had been fall- 
plowed. In the spring of 1912 the whole of it had been planted to corn, 
but on June 14, in order to provide a fallow area for the study, we hoed 
out all the plants on a tract 6 rods square, and after this had the plot 
cultivated along with the rest of the field. It was kept entirely free of 
weeds, thus serving as a summer fallow, while the rest of the field was 
typical of corn land. In the latter the samples taken up to that time 
between the corn rows may be regarded as quite representative of fallow 
as well as of corn land. 
The fourth area, a tract of exposed subsoil, S, lay beside a new inter- 
urban line, in preparing the grade for which the soil had been removed 
to a depth of 3 or 4 feet. Throughout the crop season we kept this 
exposed subsoil free of weeds by hoeing, but gave it no other cultivation. 
With each heavy shower there was a great loss from run-off, as the 
surface was hard and had a very gentle slope, while on the other tracts, 
which were almost level, there was practically none. 
All the places in fields J, G-F, and S where samples were taken were 
sufficiently far from trees and alfalfa plants to avoid any draft upon 
the soil moisture by roots, but this was not the case in field M which was 
surrounded by alfalfa, and itself carried a few alfalfa plants. 
The moisture conditions within the surface foot are shown in Tables 
IX to XII, while Table XIII indicates the general conditions in the 
underlying subsoil. 
