Mexico weekly ledger., 1893-06-15
A~BSORPTIVE POWER OF SOILS FOR NER
FERTILIZERS.

1t is a fact known from time immemorial that soil possesses the
power of removing from water passing through it certain impurities.
Liquid barn yard manure shaken with earth and placed upon a filter
ing cloth produces a clear, odorless, coloress and, in a measure,
from most of its saline constituents and fit for domestic use. Salts.
coloring matter and the foul smelling products of decay are alike
removed and held back by earth, of which many practical and far
reaching applications n made to-day; but though these facts have
been known for nearly two thousand years and excited the curiosity
altogether an acquisition of recent years,
Tests, to prove the above statements, had often been made but
their connection with agricultural problems was suggested for the
first time in 1919 by an Italian investigator, whose pioneer work was
slowly extended and enlarged by.others' until Way, an English
chemist, published in 1850 a comprehensive series OF experiments on
the power of soil absorption and thus pointed the way to our present
investigators have each contributed his fair share to this general
result. To understand the Importance to agriculture of this ABSORB
to plants of the so called ash constituents was necessary; how recent
our knowledge of this necessity is may be judged from the fact that a
Are the ash constituents produced by the plants and are they nee
cssary to their existence to which an answer was furnished in 1912!
negative of the former and affirmative of the latter, a n answer SO
full and clear and comprehensive as to settle for ever all doubts on
the subject
This knowledge then, viz, that ash constituents are necessary to
the plant and ar derived exclusively from the soil, led Immediately
to the conclusion that the annual removal of these constituents by the
crops grown upon il must sooner or later result in exhaustion and a
consequent decrease in fertility, a fact so well known at the present
uents, which arr thus constantly drained off from the farm and by
their presence or absence render a soil productive o II sterile? Not all
need be mentioned here since only three are of practical importance
and deserve considerahon-potash, phosphorc acid and nitrogen.
Modern agriculture with its intensive method of farming. removes
annually large quantities of these bodies from the soil and the time
must come when the accumulahons of centuries ar exhausted and
the he outgo must De made good py the applea ZION OF m mn NJ; e dt 1eftnlae Rs:
farmer to learn something of the principles which come into play in
the selection as well as application ot the proper mineral ertl1zer
for lands that no longer return a fair share of profit for the labor
spent upon their cultivation.
If plants derive their ash constituents from the soil it is plain
they obtain them by the activity of their roots; these must find them
in solution and the solution must come to them since they cannot 60
to the solution. Potash, %phosphorc acid and nitrogen, in the form
of ammonia, let us say. must therefore be soluble in the soil; must
form a solution, highly diluted it is true, and must circulate around
and about the roots. But such a solution is in many respects peculiar
and before its properties were sufficiently understood errors and false
conclusions with often much vituperation. was the share of every
Investigators labors.
When in 1912 the necessity of the ash constituents to the plant
was proven, a Jealous desire on the part of scientific as well as
practical men led to the employment of chemical analysis to determine
the cause of steriltv in soil. Thousands of soil analyses were made
with the incontestable final result that many soils, in which potash,
phosphoric acid and nitrogen existed in sufficient amounts, were,
unproduciye if not sterile, and that chemical analysis, as carried on
in the way then employed, was unable to give a n answer to the
question; these bodies might exist in the soil but" the plants could
make Use of them only in solution, and analysis did not ascertain this.
1t was worthless to continue in the old way, and a new n w a sug-
eested that proved as promising at the start as the former but led
finally to the same conclusion. The roots require solutions for their
absorption of mineral constituents Why not make a solution of a SOIL
wash it with water and analyze the liquid, to discover deficiencies
in its make upf 1t seemed a plain enough matter, but when carried