The Norfolk weekly news-journal., 1909-11-19

FIG. v-HOw FERTILITY Is WASTED
spring up. make considerable growth
and die down and rot. In the course
of few years the humus supply will
be renewed, locked up elements of fer
tility will become available. and the
field will again produce profitable
crops.
If rotation is practiced so as to even
up the demands on the soil, with
clover or some other legume to gather
nitrogen from the air. the soil will
continue productive for much longer
time. Even then 1t will not keep on
yielding profitable crops always. Com
mercial fertilizers may help to stave
off the day of reckoning, but after the
farmer has contributed hundreds Of
dollars to the pockets of the fertilizer
manufacturer he will find that even
this method of maintaining fertility
cannot be depended upon.
Keeping tho Soil Productive.
There are three factors on which
the productivity of the soil primarily
depends-the amount of available min
eral plant food elements which it con-
tains. its physical condition and the
amount of moisture it will hold. Nj
trogen. one of the three most important
chemical elements in the soil, can be
obtained from the air in unlimited
quantities by the use of legumes. such
a G f.ln n ,hIf Fol-
phosphorus and potassium. are present
IN most soils in fairly large quantities,
although much of the supply is in
unavailable form. Good tillaga and
well planned rotations do much to
make these elements available. When
the total supply becomes low 1t can
be renewed by the application of ferti-
lizers. This is all. however, that fer
tilizers will do. They will not i'm.
prove the physical condition of the
soil nor increase its moisture holding
capacity.
The use of liberal amounts of clover
IN the rotation will add to the humus
supply OF the soil and so increase its
moisture holding capacity. Humus
acts like sponge, forming a store
house for water that would otherwise
be wasted. Humus also improves the
physical condition of the soil, making
1t lighter and mellower. Take nan
ful of clay and painful of rich black
surface soil. wet them thoroughly and
place them in the sun. When the CLAW
is dry 1t will be baked almost as hard
as brick, while a little stirring will
make the black dirt as mellow as ever.
This difference In the two soils Is due
solely to humus.
The humus supply cannot be main.
tanned by the use OF clover unless
crop Is pIowed under at frequent in
tervals. 1t takes considerable time
for this clover TO rot enough to form |
humus, and the turning under of so
large an amount of green matter at
once is liable to make the land sour"
This condition can be corrected by the
use OF lime, but this means trouble |
and expense.
The Value Of Manure.
The only way to keep the soil in the |
highest possible state of productivity |
Is TO keep live stock and apply the
manure TO the land. Barnyard manure
adds large amounts OF the elements OF |
Fertility to the soil. An average of
40 per cent of the nitrogen. phosphorus
and potassium in the food eaten is
passed out In the manure. This per.
centage is highest In fattening animals
and lowest In young stock The efe-
ments of fertility removed when grain
is sold as compared with those remov
ed by live stock are strikingly shown
In the following table. The prices of