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The Business Farmer’s Paper 
VoL. LXXVI. NEW YORK. NOVEMBER 24, 1917. No. II.IT. 
The Lipman Process of Making 
Superphosphate 
What the Sulphur Does to Compost 
I have road the statement about Dr. Lipman’s patent 
process for using sulphur in the compost heap for 
making phosphate rock available. He states that the 
bacteria in the soil produce the sulphuric acid by 
oxidizing the sulphur. Would not the sulphuric acid 
which the sulphur contains destroy these bacteria and 
thus defeat the purpose of all this work? How is the 
Ijroccss carried on? j. B. ic. 
OW THE WORK IS DONE.—The process pro¬ 
posed by me for the making of available phos¬ 
phates through the oxidation of sulphur to sulphuric 
acid by bacteria has been carefully studied in our 
laboratoides from all angles for the past two years. 
We have been studying the conditions under which 
the sulphur is changed to ticid l)y microscopic or¬ 
ganisms, and we know with much accuracy how the 
sulphur, as it is changed into acid, attacks the insol¬ 
uble rock and makes it available. In proimsing the 
•cultural chemists, but by actual tests with plaut.s 
in which wo showed that the phosphate rock made 
availalde by the sulphur method .gave just as good 
results a.s .standard acid .phosphate. The tests were 
made with a number of different crops, and the re¬ 
sults reported in a paper published by myself and 
II. C. McLean in the October issue of “Soil Science.” 
It may be interesting to point out, in this connection, 
that our investigations demonstrated that buckwheat 
Avill utilize in.solublo pho.sphates in ground phosphate 
rock almost as readily as the available phosphoric 
acid of acid phosphate. Therefore, we are led to 
suggest that it might be entirely feasible for farmers 
to apply ground riliosphate rock, which is the cheap¬ 
est source of phosphoric acid, to grow buckwheat 
as a cover crop, and to plow it under so that the 
phosphoric acid stored in the buckwheat crop may 
be m.ade readily avjiilable as the buckwheat decays. 
V'e find. also, that buckwheat and Soy beans will 
readily use the insoluble potash present in the green 
in a Coursd of lectures which 1 gave at the rniver.s- 
ity of Tennessee in July, 1900. (itlierwise state<l. 
the gain as to phosphoric acid by keeping the soils 
strongly acid would be more than offset by the loss 
of nitrogen through the inability of the landowner 
to grow the nitrogen-accumulating and soil-improv¬ 
ing crops like the clovers. Alfalfa, vetches, cow peas, 
etc. 
ADVANTAGES OF COMPOSTING.—The proces.s' 
projiosed by me for the making availalile of insoluble 
pho.sphates is liasod on tlie fact that ground pho.s- 
])hate rock and ground sulphur are intimately mixed 
and supplied with some .soil containing the micro¬ 
scopic organisms that can change sulphur into sul¬ 
phuric acid. It might be claimed that, instead of 
letting the change take place in the comipost heap, 
the farmer might directly apply a mixture of sul¬ 
phur. ground phosidiate rock and some soil contain¬ 
ing the necessary organisms. This, however, would 
not be entirely satisfactory, since the sulphur would 
Three Generations of Hereford Cattle. See “Beef Making in New England.” Page 1356. Fig. 629 
proces.s, I recognized that the phosphate rock would 
neutralize a part of the acid as it was formed, so 
that the bacteria and fungi re.sponsible for the 
change would not be hindered in their action by 
too great an accumxilation of free acid. In other 
words, the phosphate rock combines with the acid 
and encourages the changing of the additional quant¬ 
ities of sulphur into sulphuric acid. 
SULPHUR AND SULPHURIC ACID.—J. B. K. 
is right in saying that sulphuric acid, accumulating 
in any considerable quantity, is injurious to germ 
life. He is wrong, on the other hand, in saying 
that sulphur contains a certain quantity of sulphuric 
acid and that .this acid makes the phosphate rock 
available. There is no guesswork about our invest¬ 
igations. The sulphur was carefully tested for sul¬ 
phuric acid, and the rate of change of the free 
sulphur into sulphuric acid was studied from day 
to day. We demonstrated that the insoluble phos¬ 
phate was changed into available phosphate not 
only by chemical methods used by the ollicial agri¬ 
sand marls (>f New Jer.soy. Hence, it might be quite 
practicable to use ground phosphate rock and green 
sand marl for the growing of buckwheat and Soy 
lasans and, when these are plowed under, the soil 
would be enriched in available ithosphoric acid, 
available potash and the nitrogen accumulated by 
the Soy beans. 
ITIOSPHATE ROCK ON ACID SOIL.—A soil 
which is strikingly acid in character will respond 
to applications of ground phosphate rock. Experi¬ 
ments which we are now conducting in the cran¬ 
berry bogs in New Jersey show that ground phos¬ 
phate rock and bone meal give just as good results 
as a source of available phosphoric acid as does 
acid phosphate. Hence, in cranberry growing, ground 
phosphate rock and bone meal are a satisfactory 
source of .phosphoric acid. On the other hand, soils 
that are acid enough to allow the ready utilization 
of the inert phosphoric acid in ground phosphate 
rock are too acid for the normal growth of clover. 
Alfalfa and other legumes.. This fact I pointed out 
be distributed in a large quantity of soil and the 
acid foiuned from the sulphur would act on the iron 
and aluminum compounds in the soil so that the 
phosphate rock would not be attacked except in a 
very mild way. In the compost heap, on the other 
hand, we have the concentration of both phosphate 
rock and the sulphur and, after the action is over, 
a relatively slight amount of acid would remain un¬ 
combined, so that there would be slight danger of 
increased soil acidity. Of course, it would be true 
of this process, as is tnie of acid phosphate, that 
the soil should be limed from time to 'time in order 
that it be kept in good condition for the activities 
of both bacteria and plants. Jacob g. lipman. 
Sweet Clover and Hulled Seed 
^lay I speak a word of caution about sowing nn- 
hulled Sweet clover in Winter, or at any time? Be¬ 
yond a doubt we have much yet to learn as to the 
best management of this remarkable plant, which ia 
