t commercial fertilizers. It is
the rule that he refuses to consider their use until the decrease in
crop yields becomes so serious that necessity drives. If his land is
not contributing its fair share of grain, vegetables, etc., to the
markets, but has all its products converted into meat or milk, the
supply of available plant-food may remain sufficient for so long a time
that the matter cannot have any interest for him. If the land is
producing some crops for market, there is reduction in its mineral
store. It is the rule that the boundary of profitable use of commercial
fertilizers pushes westward from the older and naturally poorer
seaboard states about one generation after need shows in the crop
yields. Lack of knowledge, the association of the use of commercial
fertilizers with poor land, and some observation of the unwise use of
fertilizers, combine to create a lively prejudice. They are viewed as
stimulants only, and costly ones at that.

Are Fertilizers Stimulants?--Some words carry with them their own
popular condemnation. We are accustomed to draw a sharp line between
foods and stimulants, and to condemn the latter. To stimulate is to
rouse to activity. Tillage does not add one pound of plant-food to the
soil, and its office is to enable plants to draw material out of the
soil. It makes activities possible that convert soil material into
crops. Fertilizers add plant-food directly to the soil, and it is also
to their credit that their judicious use favors increased availability
in some of the compounds already in the soil. The greater part of the
labor put on land is designed to make plant-food available, either by
providing moisture, or ease of penetration of plant-roots, or activity
of bacteria, or other means that will permit plants to remove what they
need for growth. Fertilizers supply fertility directly and indirectly,
but it is their direct service in meeting a deficiency in plant-food
that affords all needed justification for their use by practical
farmers.

Referring to the thirty years' soil fertility experiments of the
Pennsylvania station, Hunt says that they "show that there is nothing
injurious about commercial fertilizers. For thirty years certain plats
in this experiment have received no stable manures. No organic matter
has been added to the soil except that which was furnished by the roots
and stubble of plants grown. These plats are not only as fertile as
they were thirty years ago, but th