sour that clover
bacteria cannot thrive, and there is ten-fold more waste in letting
land fail to obtain the organic matter and nitrogen clover should
supply. When land-owners refuse to let their soils remain deficient in
lime, clover will come into a prominence in our agriculture that it
never previously has known.

Methods of Seeding.--It is a common practice to sow clover in the
spring, either with spring grain or with wheat or rye previously seeded
in the fall. This method has much to commend it. The cost of making the
seed-bed is transferred to the grain crop, and there is little outlay
other than the cost of seed. Wheat and rye offer better chances to the
young clover plants than do the oat crop which shades the soil densely
and ripens later in the summer. The amount of seed that should be used
depends upon the soil, the length of time the sod will stand, and the
purpose in growing the clover. When soil fertility is the one
consideration, 12 to 15 pounds of bright, plump medium red clover seed
per acre should be sown. A fuller discussion of the principles involved
in making a sod and of seed mixtures is given in Chapters VII and VIII.

Fertility Value.--Attempts have been made to express the actual value
of a good clover crop to the soil in terms of money. The number of
pounds of matter in the roots and stubble has been determined, and
analyses show the percentage of nitrogen, phosphoric acid, and potash
contained. The two crops harvested in the second year of its growth
likewise have their content of plant-food determined. If the total
amounts of nitrogen, phosphoric acid, and potash have their values
fixed by multiplying the number of pounds of each ingredient of
plant-food by their respective market values, as is the practice in the
case of commercial fertilizers, a total valuation may be placed upon
the clover, roots and top, as a fertilizer. Such valuation is so
misleading that it affords no true guidance to the farmer. In the first
place, the phosphoric acid and potash were taken out of the soil, and
while some part of these materials may have been without immediate
value to another crop until used by the clover, no one knows how much
value was given to them by the action of the clover. Again, no one
knows what percentage of the nitrogen in the clover came from the air,
and how much was drawn from the soil's stores. The proportion varies
with the fertility of the land, the percentage of nitrogen taken from