land, although it does add organic matter and nitrogen.

Varieties.--There is only one variety of alfalfa in common use in this
country, and the western-grown seed sold upon the market is known
simply as alfalfa. Bound up in this one so-called variety are many
strains differing in habit of growth, and their differentiation will
occur, just as it has in the case of wheat, and is now proceeding
slowly with timothy. The eastern grower at present should use the
variety of the west that is furnishing nearly all the seed produced in
this country. There is a variety known as Sand Lucerne that has shown
value for the light, sandy soils of Michigan. The Turkestan variety was
introduced for dry, cold regions, but does not produce much seed.

Clean Seed.--Care should be exercised to secure seed free from
impurities. If one is not a competent judge, he should send a sample to
his state experiment station for examination. The practice of
adulteration is decreasing, but the seed may have been taken from land
infested with pernicious weeds.

The impurity most to be feared is dodder. There are several varieties,
the seeds varying in size and color. The same pest may be found in
clover fields, but the injury is less because the clover stands only
two years. The dodder seed germinates in the soil, and the plant
attaches itself to the alfalfa, losing its connection with the soil and
forming a mass of very fine vines that reach out to other alfalfa
plants. In this way it spreads, feeding on the sap of the host plants
and killing them.

When the infestation is in only a few spots in the field, the remedy is
to cover with straw, soak with kerosene oil, and burn. All the
infestation at the edges of these spots must be destroyed.

When the dodder is too widely distributed throughout the field to
permit of this treatment, the only course is to plow the field at once,
and to grow cultivated crops for two or three years. It is believed
that no variety of dodder produces seed freely in the eastern states,
and that the hay made from the first crop of alfalfa or red clover will
not contain any seed of this pernicious plant.

The Seeding.--When alfalfa has become established on eastern farms, the
difficulties in making new seedings will be smaller. The experience of
growers will save from mistakes in selection of soils and preparation
of the ground, and the thorough inoculation with the right bacteria
that can come only with time will do much t