The morning news. [volume] (Savannah, Ga.) 1887-1900, 1891-01-12
Manurial Eequirem ents Of Grapes.

In the last few years considerable advance
has been made IN the knowledge of all that
relates to the application of manures, says
J. j. Willis in Gardeners Chronicle, and
not the least important is that which sho ws
us that there is a direct connection between
the supply of nitrogen to a plant, and the
formation of non-nitrogenous substance.
In experiments at Rothamsted with the
sugar-ylelding root crops, it was found that
there was more sugar produced the larger
amount of nitrogen applied as manure, al
though not In prop 1rtlon to the amount
supplied. Also that the efficiency of a
given supply Of nitrogen is greatly depen-
dent on the available minerals of the soil.
Taking the mean of many inv, stigations in
which potash formed an ingredient in the
manurial supply, it was found that one
pound of nitrogen in manure yielded about
twenty pounds of sugar. Fresh ripe grapes
contain, on an average, about 20 per cent
of sugar. Now sugar is an organic sub
stance composed of CARTON, hydrogen and
oxygen, constituents which are derived from
the atm ospaere aud water So that if moth
ing were taken from the soil but pure sugar
there would be no loss of mineral cons6itl-
ents. Bat it happens in practice that nearly
the whole of the constituents of tie vine
cane and of the leaves, are lost to the soil.
Besides, the skin CT the berries, and the
seeds, contain large proportion of alkaline
salts.
1t is obvious, therefore, that in the growth
of grapes there is, besides vegetable matter,
a great loss of the mineral ingredients of the
soil. To show the nature of this loss, it may
be mentioned that a ton of grapes would
contain about nine pounds of alkaline salts,
which would be principally potash, besides
that removed by the growth OF the wood
and leaves. So that nearly as much mineral
plant food would be lost to the soil as by the
growth of a corresponding quantity of
sugar cane.
1t is extremely desirable, therefore, that
in all manurial applications to vines, both
phosphates and potash sales should enter
into its composition. Hence, we find Vile
stating that he used to think the Leg
uminose, and the potato, were the plants
which showed a special preference for pot
ash, but he now observes the vine distances
them in this respect in a most surprising
manner. In the case of the potato the sup
preston of potash manifests itself by di-
Ininution of the crop; with tho vine, how
ever, little or no fruit makes its app ar
ance, and we virtually get no crop at oil.
Further, when potash and phosphates are
lacking the leaves of the vines do not at
tain their full development In the month
of July, particularly, Prof. Vile has no.
ticed that the leaves becomes red, and
spotted with black; after which they often
become very dry, and are easily re-
duced to powder under the pressure Of the
fingers.
Experiments with grapes at the State
College of Kentucky, U. s., recently, have
shown the effects of fertilizers containing
potash aud phosphates were very marked
The vines So treated were more thrifty, and
comparatively free from blight and disease,
which was more or less destructive on vine
areas not so treated.