Vol. LV. No. 2438. 
NEW YORK, OCTOBER 17, 1896. 
81.00 PER YEAR. 
FEEDING HABITS OF VARIOUS PLANTS. 
THEIR APPETITES FOR DIFFERENT FORMS 
OF PHOSPHORIC ACID. 
Clover and Turnips Lunch on “Floats”. 
Week before last, we had an illustration of the effect 
of using a fertilizer containing only one very soluble 
form of nitrogen. This week, we wish to refer to an 
interesting experiment with phosphoric acid recently 
carried out at the Maine Experiment Station. Phos¬ 
phoric acid, as most people understand, is a very im¬ 
portant manurial element. It gives strength to the 
side. In organic forms, they come in the form of 
grain to be fed to stock and applied in the form of 
manure, or in the form of crushed bones of animals 
that lived, perhaps, thousands of miles away from 
the farm. There is a large supply of coal in the 
world, but we do not go and dig it on our own farm ; 
it is crowded together in certain parts of the earth’s 
crust that we call mines, and from the mine it is 
brought to the farm as fuel. In the same way, the 
vast proportion of the potash we use is dug out of a 
mine in Germany, and sent over the ocean to the 
American farm. Ages ago, vast stores of phosphoric 
phoric acid, yet will not make crops grow, because it 
has not been made soluble by the use of an acid. It 
is certainly one of the singular things of nature that 
this necessary phosphoric acid should be locked up in 
these tough combinations, and not left like potash 
ready for use as soon as it is ground fine. 
We have been taught to believe that the farmer 
must pay the cost of dissolving the phosphate with 
acid. Is there no other way to set this plant food 
free ? This experiment in Maine was carried out to 
try to learn whether different plants had different 
feeding habits—that is, whether a crop like corn or 
THE GROWTH OF YOUNG CLOVER. Flo. 216. 
THE GROWTH OF MATURE CLOVER. Flo. 217. 
CORN WITH DIFFERENT FORMS OF PHOSPHORIC ACID. Flo. 218. 
TOMATOES WITH SOLUBLE AND INSOLUBLE PHOSPHORIC ACID. Flo. 219. 
SOLUBLE AND INSOLUBLE FORMS OF PHOSPHORIC ACID TESTED. 
stem or skeleton of the plant, and is found in the 
seeds or fruits, just as in the animal it is found most 
prominent in the bones and brain. While phosphoric 
acid is widely diffused in nature, it is seldom abun¬ 
dant. In fact, it is one of the rarest of plant foods, 
and one most likely to be found wanting in the 
average cultivated soil. 
Nitrogen, as we know, is in the air all about us, 
and falls upon the soil in rain or snow. It may be 
added to the soil by growiDgclover or peas, and plow¬ 
ing them under or feeding them. It is not so with 
phosphoric acid and potash ; these substances must 
be brought to the farm from somewhere on the out- 
acid were packed away among rocks in Canada, or in 
bunches or nodules in various parts of the South. It 
is dug and brought to your farm in order that your 
soil may produce crops. 
Now the potash comes to you all ready for use in 
its raw state. As “muriate”, “sulphate”, or 
“ kainit ”, it is soluble in water, hence ready for use 
at once. This is not true of the phosphoric acid. 
Except in the form of very fine ground bone, this 
phosphoric acid is locked up in tough combinations 
until set free by some powerful acid. As some of our 
readers know to their sorrow, dealers often advertise 
a cheap “ phosphate ” which .contains plenty of phos- 
clover cannot make use of crude rock to better advan¬ 
tage than, say. potatoes or oat«. 
You may take a little calf only a few days old. It 
would be folly to feed that calf on ensilage, stalks 
and cotton-seed meal. It would only die on such a 
ration. Give these foods to a cow, however, le 
her make them over into milk, and feed the milk to 
the calf, and you have a satisfactory arrangement. 
Or to make it even plainer, take a nursing child and 
see how it is nourished by the change of the food its 
mother eats, into more soluble forms of nourishment 
which it can digest. Another illustration may be 
found in-aj potted’Strawberry plant, where the small 
