45o _ THE RURAL NEW-YORKER. JULY 12 
ON THE MOST PROFITABLE USE 
OF COMMERCIAL MANURES. 
( Concluded .) 
“ It is often stated that ‘ heavy applica¬ 
tions of phosphoric acid readily produce in¬ 
jury on poor, sandy soil.’ But it should be 
observed how this effect of the phosphoric 
acid is brought about. Primarily, the 
phosphoric acid acts by no means injuri¬ 
ously. Plants manured with superphos¬ 
phate appear at first more vigorously devel¬ 
oped, than those unmanured. Not till later 
does this ‘ condition disappear.’ Then the 
plants cease to develop, and their leaves be¬ 
come yellow. Hot and dry weather is 
usual at this time, and the plants die. 
They ‘ripen too early.’ The phosphoric 
acid has ' burned ’ them, as is frequently 
said. This ‘burning’ by phosphoric acid 
is nothing else than the consequence of 
early nitrogen starvation, with heat and 
drought. The small amount of nitrogen 
supplied by a sandy soil is quickly con¬ 
sumed by those plants requiring much 
phosphoric acid, and consequently much 
nitrogen. The plants then starve, and the 
effect of heat, drought and other unfavor¬ 
able circumstances on a starving plant is, 
of course, far more hurtful than on a well- 
fed one. Here, then, is the explanation 
why a crop heavily manured with phos¬ 
phoric acid finally yields, in spite of an 
early, luxuriant development, a lighter 
harvest than another which has not been 
so manured. It should be remembered that 
these ‘ evil effects of phosphoric acid ’ can 
be avoided by an application of nitrogen, 
either at the beginning, or at any time be¬ 
fore the critical period is passed Nitrogen 
salts, or more gradually acting compounds, 
as barnyard manure, green manure, ground 
meat, fish, dried blood, etc., may serve in 
such cases. 
So soon as the plant lacks nitrogen or 
other food, a luxurious consumption of 
phosphoric acid can take place. The plant 
then continually absorbs phosphoric acid 
from the soil, which it cannot assimilate 
because of the lack of nitrogen. But, if 
nitrogen is not lacking, then the danger of 
absorption of unassimilable phosphoric 
acid is not a present one. 
The necessary amount of manure cannot 
always be inferred from the necessary 
amount of food. The necessary amount of 
food for a plant, as determined by chemical 
analysis of the crop, is often essentially 
different from the amount of manure 
which the same needs, as determined by 
the fertilizer experiment. The same soil 
from which one domestic plant can take 
only 20 pounds of phosphoric acid, yields 
without difficulty 60 pounds to another. 
We must therefore determine the amount 
of manure to be given, not simply by the 
need of a crop for plant food, but with 
reference to the manurial need of the plant; 
that is, its demand for easily soluble ma¬ 
terials. 
Another question here arises; namely : 
In view of present ruling prices, of special 
aims in culture and of special qualities of 
soil, which phosphate is it most advantage¬ 
ous to use ? The principal commercial 
phosphates are superphosphate, including 
all dissolved phosphates (Peruvian guano, 
dissolved bone, etc.), ground Thomas slag 
and bone meal. These have very different 
market prices. Phosphoric acid costs per 
pound, in superphosphates, from 6 to 7 
cents; in bone meal, from 4 to 4.5 cents ; in 
Thomas slag, from 2 to 2.5 cents. What is 
the explanation of this difference in price ? 
Has the phosphoric acid a different value 
in the feeding of plants, according to 
whether it comes from superphosphates, 
Thomas slag or bone meal ? No It makes 
no difference with the plant whether phos¬ 
phoric acid comes to it from guano, bone 
meal, ground phosphorite, superphosphate, 
ground coprolite, Thomas slag or any other 
manure. 
Here, however, is the explanation. Phos¬ 
phoric acid cannot be taken from every 
manure with equal rapidity; and the 
manurial value of a phosphate, as well as 
the market price of its phosphoric acid, is 
determined relatively by the rapidity with 
which the plant can draw from it the phos¬ 
phoric acid. It is important for the agri¬ 
culturist to get returns from his outlay as 
quickly as possible. Therefore it is im¬ 
portant that phosphoric acid applied to the 
soil should become dissolved, enter into 
the roots, and in the form of vegetable 
substance be returue d at the first possible 
moment. A manure whose phosphoric 
acid comes back in the first crop, is of 
course much more valuable than one which 
returns the last portions only after six, 
eight or 10 years. Therefore the rapidity 
of the effect is all-important, if we would 
determine the manurial worth of ground 
Thomas slag, relatively to that of super¬ 
phosphate and bone meal. We must ascer¬ 
tain how rapidly the phosphates are de¬ 
composed and taken up by the plants. 
But bow do we accomplish this ? By 
what method can we determine the solu¬ 
bility of Thomas slag phosphoric acid ? 
Here is apparently no difficulty. A large 
number of chemical solvents are at our 
disposal. We can treat the ground Thomas 
slag with dilute acetic acid, citric acid, 
ammonia citrate, etc., and prove whether 
it is more or less easily and quicklv dis¬ 
solved than other phosphates. In fact, it 
has been found that all such solvents de¬ 
compose Thomas slag more quickly and 
completely than, for instance, the undis¬ 
solved coprolite meal. But this by no 
means suffices for reckoning the manurial 
value of Thomas slag phosphoric acid. 
Remarkable as it is that Thomas slag is 
dissolved with relative ease in acetic acid, 
and probable as it appears that the manur¬ 
ial value of its phosphoric acid would be 
great, this is nevertheless not yet deter¬ 
mined. In the soil there is no acetic acid, 
no ammonia citrate. There we have to do 
with the combined effect of several solvent 
powers which proceed from humic acid, 
soil water, various soil salts and the acids 
of the plant roots. How these co-operating 
agents behave toward Thomas slag, bone 
meal, supherphosphates, etc., must first be 
determined, in order to reach a definite and 
reliable statement as to the manurial value 
of Thomas slag. This testing can be ac¬ 
complished only by fertilizer experiments. 
Different series of experiments have 
shown that two pounds of phosphoric acid 
in Thomas slag produce, in the first year 
after application, the same as one pound of 
soluble phosphoric acid. It is, therefore, 
more advantageous to apply the Thomas 
slag; for two pounds of phosphoric acid 
in this cost only 4.4 cents, while one pound 
of soluble acid costs from six to seven 
cents. Two pounds of Thomas slag phos¬ 
phoric acid produced the same increased 
yield in the first crop following the appli¬ 
cation, as 10 pounds of bone meal phos¬ 
phoric acid. The bone meal, therefore, 
must be considered, in comparison with 
Thomas slag, a much dearer manure. 
Two pounds of Thomas slag phosphoric 
acid (applied in the form of ground Thomas 
slag, containing 18 per cent, phosphoric 
acid and 80 percent, fine powder) produced, 
the first year after manuring, the same in¬ 
crease of yield as one pound of soluble 
phosphoric acid. The after effect of the 
two pounds of Thomas slag phosphoric 
acid in the second year after manuring, 
was twice that of the one pound of soluble 
phosphoric acid. If, now, we allow the in¬ 
creased yield produced by one pound of 
soluble phosphoric acid to be indicated by 
100, then two pounds of Thomas slag phos¬ 
phoric acid effected in the first year, after 
manuring, a yield increase of 100. In the 
first and second years after manuring, the 
increase was 120. On the other hand, two 
pounds of bone meal phosphoric acid pro¬ 
duced, in the first year after manuring, an 
increase of 10, and in the first and second 
years after manuring, an increase of 22. 
These results show that, at present quoted 
prices, it is much more profitable to use 
ground Thomas slag as a manure than 
bone meal. Bone meal becomes effective 
very slowly, while even the coarse meal 
(the residue from sifting) of the Thomas 
slag acts more quickly. The results of my 
experiments, which have been subjected to 
rigid scrutiny, as well as the favorable ex¬ 
perience of agriculturists generally, induce 
me to recommend very highly the use of 
ground Thomas slag. It should, however, 
be procured from a reliable source, the 
percentage of phosphoric acid and of fine 
meal should be guaranteed, and a sample 
of the material received, examined for 
phosphoric acid and fine meal at the proper 
experiment station. These ingredients vary 
greatly in commercial wares. If the 
Thomas slag has less fine meal than corres¬ 
ponds to the normal of 80 per cent., it acts 
more slowly, and has therefore less value. 
Apparently, also, the phosphoric acid in a 
meal richer in this material, and conse 
quently containing less lime, becomes ac¬ 
tive more quickly than the corresponding 
quantity in a meal with more lime and less 
phosphoric acid. My experiments in this 
connection are not yet concluded. I shall, 
however, soon report more definitely upon it. 
Whether it is better to apply the crude 
salts (kainitand carnalite), or whether the 
pure and concentrated salts (potassium 
chloride and potassa sulphate), must be de¬ 
cided in the first place by the price at 
which the pound of potash is to be had in 
the different materials. Potash in local 
salt deposits is much cheaper in the crude 
than in the concentrated forms. As, how¬ 
ever, the latter contains three or four 
times as much as the former, the freight on 
the raw salts amounts to three or four 
times that on the concentrated. Conse¬ 
quently, beyond a certain distance, the 
potash of purified salts is much cheaper 
than that of the crude salts. 
In deciding this question, moreover, it 
must be remembered that the common 
salt (sodium chloride) of the crude prepara¬ 
tions has a binding effect on the soil, and 
increases its power to retain water. It is 
this effect of crude salts which improves 
the character of light soils, but which, on 
the other hand, deteriorates heavy soils al¬ 
ready possessed of too much binding qual¬ 
ity. It Is not advisable, therefore, to 
manure heavy soils with kainit or carnal¬ 
ite. Again, it must not be forgotten that 
plants appear to be sensitive—some in a 
greater degree, some less—to concentrated 
solutions of chlorides. It is best, there¬ 
fore. in the application of raw salts con¬ 
taining much chlorine, to spread them in 
the autumn, or as early as possible in the 
spring. They will then exist in sufficiently 
dilute solutions in the soil before they 
come in contact with the growing plants. 
Whether it is true that potash salts, con¬ 
taining chlorine, have an unfavorable ef¬ 
fect on the quality of many crops, is yet 
doubtful. It is only proved in the case of 
tobacco, which it is better to manure with 
potassa sulphate, or, still better, with po¬ 
tassa phosphate, than with kainit. As 
has already been said, if the soil needs 
potash, it should be given enough so that 
a surplus will always be present. But it 
must be remembered that plants are much 
more sensitive to an excess of potash salts 
than to an excess of phosphoric acid. 
In general, it is of the greatest import¬ 
ance to manure clover, pease, vetches, lu¬ 
cerne and all nitrogen increasers, with 
much potash and phosphoric acid. 
Experiments have shown me that nitro¬ 
gen in green plant material acts much 
more quickly than that contained in barn¬ 
yard manure. As far as possible, there¬ 
fore, the agriculturist must fully utilize 
the atmospheric source of nitrogen, and, 
by rich applications of phosphoric acid and 
potash, put the crops in position to take 
the largest possible amount of nitrogen 
from the air. Plenty of water; plenty of 
phosphoric acid, potash and lime,—these 
are the demands made by the nitrogen¬ 
collecting plants on the soil. The nitrogen 
they provide themselves; and yet, for 
intensive farming,—for an intensive culture 
of roots, grain and oil crops, tobacco, pota¬ 
toes, etc., the nitrogen possible from the 
air is not sufficient. 
Kainit consists of one-third sodium 
chloride; and, in consequence of this 
sodium content, it acts very favorably on 
light soils. It. occasions the soil particles 
to adhere more, and increases their water- 
retaining power. 
We may now consider the application of 
Chili saltpeter. This salt contains nitrogen 
in a form which allows immediate absorp¬ 
tion and assimilation. It is not subjpct to 
the absorbing powers of the soil, but remains 
perfectly free, and therefore becomes 
quickly effective. A plant lacking nitro¬ 
gen, watered with a solution of saltpeter, 
shows, three days afterwards, the effect of 
the nitrogen applied. Its leaves become 
dark green,—a sign of luxuriant growth. 
Chili saltpeter presents to us, therefore, as 
does no other nitrogen manure, a means 
with which to influence quickly the devel¬ 
opment of plants. By sowing saltpeter on 
a young crop, which has, perhaps, suffered 
from frost or insect attacks, the plants are 
induced to sturdy and luxuriant growth. 
Even at a later period of vegetation, if 
necessary, we can give them nitrogen food 
in this immediately assimilable form. 
Although we possess in Chili saltpeter a 
manure freely movable in the soil, immedi¬ 
ately effective for the plant, and which is 
absorbed with great avidity, precaution in 
its use must be observed, otherwise the 
best effect possible is not secured. But 
whatever may be true here, is of equal im¬ 
portance in the case of ammonia. Under 
normal circumstances, ammonia is com 
verted, with more or less rapidity, into 
nitric acid (t. e., the form of nitrogen in 
saltpeter), and then has all its properties. 
Failures in manuring with nitrogen salts 
sometimes occur. We will seek a brief ex¬ 
planation of these failures, and means for 
their prevention. In the first place, the 
nitrogen is often not sufficiently absorbed 
by the plant. This can be the case when 
saltpeter is not applied at the right time. 
Winter grain may be manured in the 
autumn, in many cases successfully, but in 
many others not. It must be remembered 
that young plants require relatively little 
nitrogen for a sufficient development before 
the winter rest begins. A well-cultivated 
soil furnishes quite enough for this. Tn the 
experiments of Heine of Emersleben, the 
highest yields were furnished by those 
wheat fields which received no nitrogen 
manuring in autumn, and all their salt¬ 
peter in May. It is certainly incorrect to 
furnish the plant its entire supply of nitro¬ 
gen in the fall. Only sufficient should 
then be given for absorption and assimila¬ 
tion before the commencement of the win¬ 
ter rest. A surplus is unnecessary, and it 
may become entirely lost during the winter 
months, by filtration through the subsoil. 
Only on very deep and retentive soils 
should a large application of nitrogen salts 
be risked in the fall. This danger of loss 
of nitrogen by percolation attends not only 
autumn applications, but those made at 
any time. Saltpeter nitrogen in the soil is 
in condition of perfect freedom. It fol¬ 
lows, consequently, the course of the per¬ 
colating waters. Therefore, the danger of 
loss of nitrogen by drainage increases with 
(a) the length of time between the applica¬ 
tion of the manure and the absorption of 
the nitrogen by the crop; (b) the quantity 
of manure applied; (c) the percolation in 
the soil; (d) the rainfall immediately after 
application. 
Heine of Emersleben had the following 
experience in manuring winter wheat. 
With much hesitation he determined to 
apply, to his winter wheat, no nitrogen in 
the fall, and none before the first of May. 
But the success of this procedure was 
greater than that of those In which applica¬ 
tions were made in autumn, February, 
March, or even April. In this connection 
Heine says: ‘ The question, At what time 
shall saltpeter be sown ? is answered by my 
results in a manner which completely over¬ 
turns the opinions hitherto held. The 
opinion that Chili saltpeter must be sown 
over the winter wheat as soon as possible 
in the spring, is by no means confirmed. 
On the contrary, the Chili saltpeter applied 
at the beginning of May, even when the 
plants were very far developed, increased 
the yield of grain.’ 
Nitrogen holds, in plant life and in the 
economy of field culture, an entirely differ¬ 
ent position from potash, phosphoric acid, 
lime, or any other plant food. Nitrogen is 
indeed an organic constituent of plant 
substance, while phosphoric acid, potash, 
lime, etc., are only agents in the formative 
processes of organic substance, and only in 
this capacity necessary. Nitrogen, in the 
burning plant material, flies away; while 
phosphoric acid, potash, lime, magnesia, 
etc., remain behind as ash constituents. 
But the nitrogen also comes and goes by 
slower processes. It wanders from the air 
into the soil, and from the soil into the air. 
Again, it passes from the atmosphere into 
the plant, and from the plant, when it de¬ 
cays, into the atmosphere. It is continually 
passing from the free condition into the 
chemically combined, and as constantly 
back again becoming free. The three most 
important and difficult tasks in manuring 
are : To catch the nitrogen, to hold it, and 
then to obtain from it the greatest possible 
service.” 
“A CORRECTION.” 
Undku the above caption our respected 
friend and neighbor, the Orange County 
Farmer, has the following in its issue of 
June 19: *‘In our issue of May 22, we 
copied an article from Thk Rukal New- 
YoBKBR, entitled ‘ Pass Him Around.’ By 
some stupid error on the part of the editor, 
compositor or proof reader, the customary 
credit, indicating the source of the article, 
was omitted. Our punishment has been 
greater than our crime. First, The Rural 
takes us to do for omitting the credit (and 
we herewith apologize for the mistake) and 
now Mr. Childs accuses us of libeling him. 
All this for a little oversight. It is due to 
Mr. Childs, the gentleman alluded to in 
the article as endeavoring to pass off an old 
plant under a new name, to say that we 
have no personal knowledge of him or his 
business, and only copied the article, as is 
our wont in such cases, supposing our con¬ 
temporary, The Rural, was sure of its 
facts. The article reads as if we had prev¬ 
iously alluded to Mr. Childs, but such is 
not the case. 
The plant alluded to, Nepeta Glechoma, 
which The Rural said is only the old 
