-May i, 1925 Soil Mulch in Absorption and Retention of Moisture 827 
Of the total rainfall of 3.69 inches 
occurring between May 31 and July 
6, 1923, the mulched soil absorbed 
1.06 inches. This was 28.7 per cent 
of the entire amount. Of the total 
amount absorbed, reference to Table 
IV shows that practically one-half was 
lost by evaporation during the re¬ 
mainder of the summer, as well as such 
limited additional rain as fell in the 
interim. By September 20 only 15.4 
area, and their proper interpretation 
should give a basis for understanding 
the somewhat divergent data from this 
region and that west of the Rocky 
Mountains. 
DISCUSSION 
In most instances data have not 
been reported by other investigators 
in a form lending itself to a true eval¬ 
uation of the mulch. The data from 
/5TFOOT 
am foot 
3m FOOT 
~ru trnn-T- X&/////////^ \Y> 
0.00 0.25 O.SO 0.75 AOO A25 /.50 /.75 
AS0/&T-0&F OO/VTF/VT/A/@&e/A/<0 
Fig. 5.—Average moisture content in acre-inches of mulched and unmulched soils in the spring and in the 
fall of the fallow year, Adams Branch Station, Lind, Wash., 1920 to 1923, inclusive 
per cent of the entire June rainfall 
remained in the mulched soil. The 
unmulched soil had absorbed and re¬ 
tained only 0.37 inch of the June 
rainfall on July 6, or 10 per cent of the 
total. By September 20, even this 
small amount had been lost, as well as 
an additional 0.58 inch from that previ¬ 
ously in the soil. 
In a general way, the conditions 
prevailing during this period and the 
final result were both very similar to 
those characteristic of the Great Plains 
the Nephi (Utah) Substation, as re¬ 
ported by Cardon (11) and by Harris 
and Jones (16), the two being in sub¬ 
stantial agreement, do, however, lend 
themselves to a measurement of the 
absorptive effect. Data after Cardon 
are shown graphically in Figure 6. 
Regarding these data, Cardon (11) 
says: 
“The facts thus brought out seem 
to indicate that at Nephi stubble land 
allows the winter precipitation to pene¬ 
trate to greater depths than fall- 
