Mar. 3, 2933 
Effectiveness of Mulches upon Soil Moisture 
735 
micrometer. The soil surface had an area of 7.07 square inches through 
which moisture could be lost. 
Six seeds of Long White Icicle radishes were planted in each set of 
apparatus, of which four germinated in the can marked “no mulch” and 
“cultivation twice a week,” and five in the can marked “cultivation 
once per week” and “ i-inch straw mulch.” Seeds were sown on June 23, 
and the experiment was terminated on July 23. Cultivation was per¬ 
formed by scarifying the surface inch of soil. 
The saving of water is a little over 2 inches greater with cultivation 
than without, and the effectiveness of cultivation in preserving soil 
moisture increases with the extent of the cultivation. The i-inch straw 
mulch saves even more moisture than does cultivation. The effect of 
cultivation and mulching upon the growth of the radishes needs con- 
DEFTH IN INCHES 
sideration. Without mulching or cultivation radishes are vigorous and 
the roots uniform, while with cultivation once or twice a week the plants 
are not so thrifty and the growth of roots is inclined to be stunted. With 
the i-inch straw mulch the growth is medium, but the roots are slighlty 
shorter and smaller than those grown without mulching. The water cost 
of one part of radishes on the dry-weight basis is, without cultivation or 
mulching, 1,009; with i-inch straw mulch, 1,045; with cultivation once 
a week, 1,422; and with cultivation twice a week, 2,262. In other 
words, cultivation and mulching save more moisture, but without culti¬ 
vation the plants make the most thrifty growth. 
So far as the conservation of moisture is concerned there is no question 
that cultivation and mulching are beneficial. The fact that with cultiva¬ 
tion and mulching the plants do not grow vigorously is due to three 
unfavorable conditions. 
First, there is too much water within the root zone, the water table 
being only 15 inches below the surface. The water has been accumulated 
to such an extent that it is far beyond the optimum moisture content of 
