732 
Journal of Agricultural Research 
Vol. XXIII, No. 9 
The word “ absorption ” as used in Table IV is construed to mean more 
than the retentive power of the mulches, but includes any water that has 
escaped through the mulches other than by the capillary action. The 
difference is brought about by the severence of the capillary system 
between the soil surface and the mulches, or, in other words, it is the 
total moisture lost minus that which is evaporated through the capillary 
action of the mulches. It may be noted that in every case there is more 
Fig. i.—D iagram showing the relative losses of moisture from sand with the application of different kinds 
mulch materials. 
loss due to absorption than to capillarity, although with the wood shav¬ 
ings the difference is trifling. From what has been said, the general 
rule may be laid down safely that an effective mulch must be constituted 
of that kind of a material which does not absorb or retain moisture 
readily and which forms practically no capillary system in itself. A 
mulch material like manure, which is very porous and therefore holds a 
good deal of moisture, should not be allowed to stand on the soil except 
in wet seasons, but must be turned under and thoroughly mixed with 
the soil before the dry season starts in, otherwise excessive evaporation 
is likely to take place and the fertility of the manure will deteriorate. 
