142 Storage of Moisture in the Soil. 
agencies for the exhaustion of moisture from the subsoil is the 
growth of weeds. To cultivate the soil in winter and spring, 
and then to allow a growth of weeds to “shade the soil” is a great 
error. Although under the cover of rank weeds moisture may 
appear even at the suriace and convey the impression of moisture- 
saving, the fact is, as fully demonstrated by experience and 
accurate caperiment, the moisture in the lower layers of the soil 
is reduced and trees are thus robbed of their supply. Weed 
growth must be resolutely suppressed during the dry season. 
Moisture Storage in the Soil—Conservation of moisture in 
the soil is not only the surety of the current season’s growth and 
fruitfulness, but is the safeguard against injury from the years of 
deficient rainfall which occur now and then in California. The 
moisture supply is equalized by this storage in the soil, and a 
surplus from the liberal rainfall of one year is held over to supply 
the lack of the next. Of course, the well-cultivated surface is 
also well calculated to catch the water. While from a hard sur- 
face much of a heavy rainfall ows off quickly to a lower level 
before it can penetrate, a loose soil retains all that falls upon 
it, except the excess, which disappears by seepage or drainage. 
It has sometimes been held by California orchardists that 
planting some tall-growing crop, like corn, so as to shade the 
young tree and the ground around it, is an advantage. This is a 
great mistake. ‘Though some rich, moist soils may afford mois- 
ture enough to grow both the tree and the corn, it is a fact that 
in most cases the growth of the corn is made at the expense of 
the tree, and sometimes almost costs its life and thrift. It 
has been clearly shown by the researches of Professor Wollny,* 
that though shading ground by a leafy growth may make the 
surface layer of the soil moister, the lower layers are invariably 
made drier, and it is in these lower layers that the tree seeks its 
sustenance. The young tree should be shaded as has been 
described in the chapter on planting, and not by a growing 
plant. 
GROWING CROPS BETWEEN TREES AND VINES. 
The possible advantage of a cover growth of clover in re- 
gions of high heat and ample moisture has been noted at the 
opening of this chapter. The rule, however, must be: Grow 
nothing whatever between the trees if you desire the full success 
of the latter. As with ail rules, this one may admit of exceptions. 
Inter-cultures in orchard or vineyard may be allowed under 
certain conditions of the soil and the purse of the grower. If 
the soil is deep and moist and rich, the cost of planting and culti- 
*Cited in Pacific Rural Press, May 3, 1879. 
