The progressive farmer. [volume] (Winston, N.C.) 1886-1904, 1899-12-05
THR FERTILIZER QUESTION.

eVen MAINTAIN the fertility or his land
by means Of commercial fertilizers
alone. By this is meant that their
continued annual use will be without
profitable returns, unless aided either
by liberal dressings of stable manure,
or by green manures from some crop
like COW peas or clover. To use only
mineral fertilizers, such as acid phos-
phate or acid phosphate and potash,
on very poor land, is almost money
thrown away. The average so called
complete or ammoniated fertilizer is
little il any better. The reason for all
this is that the excess of the mineral
elements txhausts the soil of it's nitro
gen end of it's party decayed vegetable
and animal matter, or humus and this
more quickly than if no fertilizer were
used.
The following considerations make
this subject palmer: The chemical an
ally sis Of our soils show that il we con.
slider the total amounts of plant food
they contain, the nitrogen supply
would be consumed first, next would
be phosphoric acid, and last of all, pot
ash. If we consider the plant food in
the soil to the depth Of one foot, and it
were possible to grow wheat year after
year, at the rate Of twenty bushels to
the acre, the average virgin soil of this
State would be entirely without nitro
gen in about eighty years. The phos
phoric acid would be sufficient for 40
years, while the potash would last go
years. One bushel of wheat removes
in grain and straw more nitrogen, boil
In pounds and in money value, than
the other elements combined, as fol.
lows: 2 pounds Of nitrogen, worth at
a low estimate 25 cents; 6 pounds of
phosphoric acid, worth o cents; O 8
pounds Of potash, worth cents. To
furnish this amount Of nitrogen, one
hundred poun ds of the average COM
plete fertilizer would be necessary,
which would supply enough available
phosphoric acid for fifteen bushels, and
enough potash for two bushels. This
one hundred pounds would cost, at re
tail prices, about 95 cents; If home
mixed, about 60 cents. It is evident,
therefore, that the complete fertilizer
cannot be used by itself, to build up
worn lands, or even TO maintain those
already in fair condition. 1t is still
more evident that the mineral fertili
z9rs without nitrogen, will fall even
further short of this obi ct.
The problem of improving our soils
most proftably will be solved in most
instances by the j1dicious use Of min
erRl fertiliz3r 3rs, accompanied by stable
manure and the growing of COW peae,
clover, or the like. The mistake must
not be made Of mo wing these crops for
hay and then not returning the ma.
nure, under the wrong impression that
the roots contain the most of the plant
food. Approximately one fifth Of the
total nitrogen may be considered as
left in the roots, stubble, etc. A care
fully selected rotation Of crops, in
which COW peas play prominent part,
Is the first essential in the bettering of
worn lands. Peas without mineral
fertilizer will improve fer years to
come much of our land that is begin
ming to run down; particularly that
which was naturally strongest and
best, such as our alluvial soils and our
clayey limestone soils, which are richly
supplied with mineral elements. II
mineral fertilizer be needed, general
experience teaches that acid phosphate
ia by far the more profitable. This
can be still better understood when we
have explained some principles OF acid
phosphate manufacture. The finely
ground Lime phosphate rock is treated
about an equal weight Of strong sui
phuric acid. Chemical change takes
place so that a part Of the phosphotic
acid becomes soluble in water. An.
other part, though less soluble, is made
readily available to growing crops;
while g small amount still retains its
insoIuble and unavailable character.
One other important change has taken
place. The sulphurio acid has com
bined with the lime, making lime sul
phate, commonly called gypsum or
land plaster, 80 that it forms nearly
of the total weight of the acid
1t is now we'll established
that this plaster frt es large am cunts of
insoluble soil potash. and so makes the
fertilizer element which is so much the
most abundant in our soils available
for plant use. Hence, acid phosphate
supplies phosphoric acid directly and
nntash indirectlY. The two or three