The Storaoe and [ se of soil Moisture 
59 
The data given in Table 26 were obtained from two plats 
which were being summer tilled during the summer of 1913. The 
one kept free of weeds is worked according to the usual method 
of clean fallow. The other is plowed after the weeds start in 
order to save labor in the summer tilling process. Both plats 
grew a crop of winter wheat in 1912 and at harvest time con- 
tained practically the same amount of water. It will be noted 
that where weeds were growing practically no moisture had been 
accumulated in the first three feet. Where the weeds were kept 
down, moisture was accumulated to a depth of two feet. By 
Growth of weeds on weedy fallow referred to in Table 26. 
keeping the weeds down, between two and one-half and three 
inches of water have been saved in the upper two feet of soil. 
The data given in Table 27 were obtained from an experiment 
on disking grain stubble after harvest. A portion of the field 
was disked with a weighted disk. A portion of the field where 
weeds were growing was chosen for the work before disking. The 
disk killed most of the weeds. The balance were killed with a hoe. 
The work was of short duration, due to the fact that the field 
was plowed soon after the last sampling date. About two inches 
of rain fell after the disking was done and before the final 
sampling. It will be noted from the table that the weeds used 
this water. None of it got into the soil as deep as the second 
