PRACTICAL MANAGEMENT OF SOILS 25 
gravel and a stiff heavy clay. Neither of these 
soils can in their natural condition yield satisfactory 
results, but both are capable of being transformed 
into fertile gardens. Stones, gravel, and sand, which 
is stone in minute particles, possess no nourishment 
upon which plants can thrive. Moreover, they 
have no power of absorbing moisture, and con- 
sequently plants growing in such a soil will suffer 
badly during even short periods of drought. The 
obvious necessity is to incorporate into the soil 
something of an absorbent nature, and something 
that will yield readily soluble plant food. 
Decayed vegetable matter, which we call humus, 
is the material which will supply this need. The 
best treatment of stony and sandy soil is therefore 
to bury liberal quantities of leaves, weeds, decayed 
garden refuse, and manure. Cow manure is better 
than horse manure because it is more retentive of 
moisture, and helps to keep the soil cool. 
The largest stones may with advantage be removed, 
but it is not invariably wise to take the smaller 
stones from the soil. The finer gravel tends to 
bind too closely if no stones are left to keep it open, 
and close binding means exclusion of air which is 
essential to the healthy growth of plants. Another 
point is that although stones help to drain the soil 
of moisture they also check evaporation, in proof 
of which assertion we may point out that the soil 
immediately under a stone is always moist even 
when the surrounding soil is parched. 
