40 
THIRTEENTH REPORT. 
SOIL AND SOIL PROBLEMS FROM THE STANDPOINT OF THE 
CHEMIST. 
A. J. PATTEN. 
From the standpoint of chemistry the soil is a conglomerate mixture 
of definite inorganic compounds resulting from the disintegration of 
rocks, together with the organic remains of plant and animal life in 
various stages of decomposition, water and gases. 
It was early supposed that all the changes taking place in the soil were 
chemical in their nature, it was also believed that all the phenomena 
of plant growth were essentially chemical. The following quotation is 
taken from Johnston’s Agricultural Chemistry: ‘‘The art of culture 
indeed is almost entirely a chemical art, since nearly all its processes 
are to be explained only on chemical principles. If you add lime or 
gypsum to your land, you introduce new chemical agents. If you irri- 
gate your meadows, you must demand a reason from the chemist for the 
abundant growth of grass which follows.” Thus, according to Johnston 
the knowledge of soil conditions was only limited by the lack of knowl- 
edge of chemistry. 
About the middle of the nineteenth century Liebig formulated his theory 
which he expressed in the following four law's: 
First — “A soil can be termed fertile only w-lien it contains all the ma- 
terials requisite for the nutrition of plants, in the required quantities 
and in the proper form.” 
Second — “With every crop, a portion of these ingredients is removed. 
A part of this portion is again added from the inexhaustible store of 
the atmosphere ; another part, however, is lost forever if not replaced 
by man.” 
Third — “The fertility of the soil remains unchanged if all the ingredi- 
ents of a crop are given back to the land. Such a restitution is effected 
by manure.” 
Fourth — “The manure produced in the course of husbandry is not suffi- 
cient to maintain permanently the fertility of a farm. It lacks the con- 
stituents which are annually exported in the shape of grain, hay, milk 
and live stock.” 
The promulgation of this theory naturally placed an added emphasis 
on the value of the inorganic plant-food constituents and it w'as believed 
that with the results of a chemical analysis of a soil it would be possible 
to determine its crop producing power and likewise its fertilizer require- 
ments. However, it soon became evident to agricultural chemists that 
there was no definite relationship between the productive capacity of a 
soil and its content of nitrogen, phosphoric acid and potash. 
Many people, however, today believe that the chemist needs only to 
make an analysis of a soil in order to advise the proper kinds and 
amounts of fertilizer to be used and I fear that this idea is being encour- 
aged by some soil investigators. 
The amount of so-called plant-food in the soil is only one of the factors 
