ould be given to the production of clovers in such areas.

=Renewing.=--Because of the comparatively short life of several of the
most useful of the varieties of clover, no attempt is usually made to
renew them when they fail, unless when growing in pasture somewhat
permanent in character. To this, however, there may be some exceptions.
On certain porous soils it has been found possible to maintain medium
red clover and also the mammoth and alsike varieties for several years
by simply allowing some of the seed to ripen in the autumn, and in this
way to re-seed the land, a result made possible through moderate grazing
of the meadow in the autumn, and in some instances through the absence
of grazing altogether, as when the conditions may not be specially
favorable to the growth of clover.

It is not uncommon, however, to renew alfalfa, by adding more seed when
it is disked in the spring, as it sometimes is to aid in removing weeds
from the land. The results vary much with the favorableness of the
conditions for growing alfalfa or the opposite.

In pastures more or less permanent in character, clovers may be renewed
by disking the ground, adding more clover seed, and then smoothing the
surface by running over it the harrow, and in some instances also the
roller. This work is best done when the frost has just left the ground
for a short distance below the surface.

Some kinds of clover are so persistent in their habit of growth that
when once in the soil they remain, and therefore do not usually require
renewal. These include the small white, the yellow, the Japan, burr
clover and sweet clover. In soils congenial to these respective
varieties, the seeds usually remain in the soil in sufficient quantities
to restock the land with plants when it is again laid down to grass.
Nearly all of these varieties are persistent seed producers; hence, even
though grazed, enough seed is formed to produce another crop of plants.

=Clovers as Soil Improvers.=--All things considered, no class of plants
grown upon the farm are so beneficent in the influence which they exert
upon the land as clovers. They improve it by enriching it; they improve
it mechanically; and they aid plant growth by gathering and
assimilating, as it were, food for other plants.

All clovers have the power of drawing nitrogen from the air and
depositing the same in the tubercles formed on the roots of the plants.
These tubercles are small, warty-like substances, w