126 DRY-FARMING 
thus caught will slowly work its way down into the 
lower layers of the soil. Deep plowing is always to 
be recommended for successful dry-farming. 
In humid districts where there is a great difference 
between the soil and the subsoil, it is often dangerous 
to turn up the lifeless subsoil, but in arid districts 
where there is no real differentiation between the 
soil and the subsoil, deep plowing may safely be rec- 
ommended. True, occasionally, soils are found in 
the dry-farm territory which are underlaid near the 
surface by an inert clay or infertile layer of lime or 
gypsum which forbids the farmer putting the plow 
too deeply into the soil. Such soils, however, are 
seldom worth while trying for dry-farm purposes. 
Deep plowing must be practiced for the best dry- 
farming results. 
It naturally follows that subsoiling should be a 
beneficial practice on dry-farms. Whether or not 
the great cost of subsoiling is offset by the resulting 
increased yields is an open question; it is, in fact, 
quite doubtful. Deep plowing done at the right time 
and frequently enough is possibly sufficient. By 
deep plowing is meant stirring or turning the soil 
to a depth of six to ten inches, below the surface of 
the land. 
Fall plowing for water storage 
It is not alone sufficient to plow and to plow 
deeply; it is also necessary that the plowing be done 
