The Storage and Use of froil Moisture 
39 
The curves shown in Chart V represent the moisture content 
in a brome grass field and also a field which was in corn in 1908. 
The brome grass was seeded in 1905. The moisture content is 
practically the same in the two fields in the spring. The cultivated 
field soon begins to increase in moisture content, reaching its 
maximum in June and holding it until late in July. At the time 
that the crop required most water the soil was filled to almost 
full carrying capacity. The brome grass field did not accumulate 
much water tho the rainfall was high, as shown by the heavy, 
solid line. These curves illustrate again the effect of tillage and 
plant growth on the amount of water accumulated in the soil. 
The fields are adjacent, and the difference shown is doubtless due 
to the tillage in the cornfield, which retained more of the rain- 
fall, and the growth of brome grass which used the water as fast 
as it came. The corn was young and not using much water until 
in July. As compared with the grass field there were far fewer 
plants on a given area to use water. 
EFFECT OF CULTIVATION. 
Cultivation is the one practical means for storing moisture in 
the soil on any considerable acreage. Our experience shows that 
summer tillage is the most efficient method for storing water 
which we have followed. A number of other methods, however, 
have been studied, to determine their effect. In the tables rela- 
tive to the effect of the condition of the surface, it was shown that 
a cultivated surface would catch more water than a smooth sur- 
face. The difference that will be shown between the amount of 
water held by a cultivated surface and that held by a smooth 
surface is greater during heavy rains than during light rains. It 
has also been found that plowed ground or listed ground usually 
catches more water from any certain rain than does a surface 
which has been disked. Cultivation not only puts the surface in 
shape to catch the rain but is the means by which the moisture 
is saved after it has gotten into the soil. By cultivation, weeds 
are killed and thereby prevented from using the water, and the 
surface is loosened, forming a soil mulch which reduces evapora- 
tion from the surface. 
In the following tables are given data obtained relative to 
the effect of cultivation. Space allows for only a small portion 
of the data which we have on any of these subjects. The results, 
however, are usually quite similar and we have aimed to show 
only representative results. Many times the weather conditions 
are such that no great difference is shown between one method 
and another. In other cases a greater difference is found. 
