The Storage and Use of Soil Moisture 
55 
given area and not to less ability of the plants to get water. 
Much the same results have been obtained from growing cane in 
rows. When the cane is drilled over all the ground and a greater 
number of plants must be supported, more of the water is used. 
The table shows that the corn feeds to a depth of at least four 
feet in this soil. 
Winter wheat feeds deeper than corn or spring grain. It uses 
water from the sixth and the seventh foot. The difficulty in de- 
termining this point has been to get enough water in the soil at 
those depths so that the break in moisture content would show 
plainly. Many times there has been no available water in those 
sections even tho the field had been summer tilled. The evidence 
is that the roots penetrate to six or seven feet when there is 
available moisture. This is in accord with work done by the 
Wyoming Station and reported in an unnumbered pamphlet. A 
winter wheat plant was dug out and showed roots about six 
feet long. 
EFFECT OF WEEDS. 
As much water is required to grow a pound of dry matter in 
weeds* as is required to produce the same amount of dry matter 
in some of the farm crops. From the standpoint of the farmer 
who is farming under a limited rainfall, weeds are his worst 
enemies. Any water used by weeds is lost to the crop. It is 
hardly practicable to keep all weeds down, but the crop is usually 
cut short to the extent that it has been robbed of the water by 
weeds. 
In the following tables we give data showing the effect of 
weeds on soil moisture. Weeds have the additional harmful 
effect of using available plant food. and. if allowed to use all 
the available water, leave the soil in such a dry condition that 
extra labor is required to get it into a good state of tilth. 
* Bui. No. 284, Bureau of Plant Industry, U. S. Dept. of Agr., by Briggs 
and Shantz. 
