The star. (Reynoldsville, Pa.) 1892-1946, 1899-07-26
Land Plaster and Glover.

The extraordinary elect which gyp-
sum or land plaster has on the clover
growth has long been puzzle to
scientists. II is not the lime which
the gypsum contains, for applications
of pure carbonate of lime, though
helpful to clover where the soil is de-
ticient in that mineral, do not produce
the marvellous effects which very
slight applications of the sulphate will
under favorable conditions develop.
II is doubtless the strong affinity of
sulphuric acid for water that is Mt the
bottom of this mystery Wherever
gypsum has been sown on plants they
will be covered so heavily with dew
that some of the dew will be shaken
of the leaves and fall upon the soil.
Where the plaster has been sown early
and is washed into the soil it con-
denses moisture into water from air
that is already in the soil, and as this
air contains small amount of am
monia, it furnishes just the stimulus
that the clover roots require to grow
the nodules which develop nitrogen
from the air in the soil by decompos-
ing it. Probably there is in the air
at no time more than a small fraction
of ammonia, but by uniting this with
water, so that the roots can take it
mp, they are enabled to grow the nod
ules that have the power to make full
eighty per cent. of the air, which is
the proportion of free nitrogen it con-
tains, available MS plant food.
The best results from gypsum are
secured by sowing it early, so that
spring and even winter rains and
melting SHOWS can carry some of it
into the soil, and then with clover
follow this up with occasional appli-
cations during the early part of the
season. The longer the dew remains
ON clover leaves in the morning the
better its growth will be. 1t is differ
ent with corn, which loves warmth,
aud which is sometimes injured by
applying gypsum alone on it early in
the season; but mixture of gypsum
and wood ashes or potash in other
forms is always helpful to corn. As
the gypsum condenses the moisture
the slight trace of ammonia unites
with the potash and makes saltpetre,
which is one of the most stimulating
fertilizers known. Another time when
gypsum and potash can be proftably
applied to all plants is during severe
drought, when it seems as though
there was no moisture in the air, and
even in the morning there will be
very slight dew fall. The gypsum
always makes heavier dew fall, and
this moderates the effect of dry
weather by preventing evaporation of
moisture from the leaves of plants.
Pens and beans being leguminous
plants are also greatly helped in
growth by applications of gypsum
and potash, both Of which they re-
quire in producing their seed. The
gypsum alone will make large growth
of haulm, but it will not produce seed
in proportion unless potash is also
supplied. This is also true in grow
ing clover seed. A liberal dressing of
potash early in spring will cause the
plants to grow heads filed with seed,
while if only gypsum is sown it is
probable that most of the clover heads
will be empty. Too much stable
manure which is rich in heterogeneous
fertility produces the same effect as
the gypsum. 1t is, in fact, because
the latter supplies available ammonia
by condensing it from the air that it
makes an excessive leaf growth, which
is very rarely accompanied by large
seed crop. We have seen many fields
that in the second crop of clover would
cut ton or more of haulm to the
acre that produced less than bushel
OF clover seed, while growth of less
than half ton of clover had its heads
so filed with seed that it yielded four
or five, and in one case we knew six
bushels of cleaned seed per acre.
This is, we think, nearly always the
difference wi h a greater or less sup
ply of potash in the soil makes in all
crops that are grown for seed, while
the large growth of haulm with little
seed is the result OF relying too ex.
clusively ON gypsum as a fertilizer.