The Savannah morning news., 1903-06-29
The Availability OF Fertilizers.

Most of us who have studied the true
worth of fertilizers and manures have
often wondered why we must use
quickly available potash salts and acld
German potash salts and acid phos-
nhate) with manures and green ma
nures, says a writer in Country Gentle
man. We know very we'll, to cite an
example, that farmyard manure OF
average grade contains as much potash
as nitrogen and half as much phosphor-
ic acid. Now these proportions of plant
food are suitable for all general farm
ing crops, yet the use of such manures
always gives evidence of excessive MI
trogen manuring when used in sulh-
cient quantity. We know the potash
and phosphate are there but we also
know it is not effective, though it would
seem it ought to be, as the same pro-
cess which liberates the nitrogen should
also Hberate the other elements or
plant food. AS a matter of fact, how
ever, the potash and phosphoric acid
are not made available as quickly as
is the nitrogen.
To follow this through, the growth
of the crop when only farmyard ma
nure is used suffers from lack of all
plant food except nitrogen, but the
roughage growth such as weeds, stalks,
ETC., makes a good strong growth I'M
til checked by cold weather. In the
spring the decay of this vegetable sub
stance is very rapid, and much of its
plant food escapes by drainage where
cover or catch crops are not used. In
this way the loss of nitrogen, take the
season through, is less than of either
potash or phosrhoric acid; hence the
need of potash and phosphate manur-
ing in excess of the seeming needs of
the crop. The same thing comes up in
clover farming. 1t is often asked why
potash and phosphateS should be used
on a clover sod turned under, when
the clover must contain nitrogen, pot
ash and phosphoric acid in such pro-
portions as to suit the food need of
most crops. AS a matter of practical
fact, However, these mineral fertilizer
elements are needed and are profitably
used, as all farmers who have studied
this matter know.
1t is a fact that the nitrogen is more
completely utilized in manures and fer
tilizerS than the other two elements.
and this is of course because it more
quickly takes an available form. After
ALL the usefulness of plant food is not
so much the fact of availability as hav-
ing this availability at the right time.
freely available at time when the ap-
proach of cold weather and natures
provision of dry weather shall have
forced a maturity; it is then too late
to do any good. AS a broad general
principle, therefore, give a somewhat
free rein to nitrogen, but look sharply
after potash and phosphates. For
quick effects, such as late spring appli-
cations or all kind of midsummer sea-
son crops use only the highly avail
able forms-German potash salts and
acid phosphate. Bone is very good In
it's way which is for fall manuring, but
even then the potash must be used.
There is no potash and but little avail
able nitrogen in bone. Acid phosphate
will not sour the land, but green ma
nure and farmyard manure will. When
either of these is used, lime must be
also used, as often as once in five
years. forty bushels per acre, but
through all this the availability prob
lem remains the same.