nnials and also
perennials. But there are some forms of perennial weeds which multiply
through the medium of their rootstocks that may eventually crowd
alfalfa. Medium red clover is usually cut twice a year, hence, in it
annuals and biennials cannot mature seed, except in exceptional
instances, and because of the short duration of its life, perennials
have not time to spread so as to do much harm.

The clovers that are most helpful in smothering weeds are the mammoth,
the medium and the alsike varieties. These are thus helpful in the order
named. To accomplish such an end they must grow vigorously, and the
plants must be numerous on the ground. When grown thus, but few forms of
weed life can make any material headway in the clover crop. Even
perennials may be greatly weakened, and in some instances virtually
smothered by such growth of clover. To insure a sufficient growth of
clover it may be advantageous to top dress the crop with farmyard manure
sufficiently decayed, and in the case of medium red clover to dress the
second cutting with land plaster. If the second growth is plowed under,
subsequent cultivation of the surface will further aid in completing the
work of destruction.

The crimson variety is sown and also harvested at such a time that the
influence on weed eradication is very marked. The ground is usually
prepared in the summer and so late that weeds which sprout after the
clover has been sown cannot mature the same autumn. In the spring it is
harvested before any weeds can ripen. When plowed under, rather than
harvested, the result is the same.

When clover is grown in short rotations, its power to destroy weeds is
increased. For instance, when the medium red or mammoth varieties are
grown in the three years' rotation of corn or some root crop, followed
by grain seeded with clover, the effects upon weed eradication are very
marked, if the cultivation given to the corn or roots is ample. Under
such a system weeds could be virtually prevented from maturing seeds at
any time, especially if the medium variety of clover were sown, and if
the stubbles were mown some time subsequent to the harvesting of the
grain crop. Such a system of rotation faithfully carried out for a
number of years should practically eradicate all, or nearly all, the
noxious forms of weed life.

=Clover Sickness.=--On certain of the soils of Great Britain and
probably on those of other countries in Europe, where clover has been
grown