26 
EXPERIMENTS ON THE EFFECT OF 
with but slightly less uneconomical consequences than generally 
appear after a liberal supply of nitrates. In the soil of dry fields 
it is furthermore liable to be converted into nitric acid, and as 
this change is much favoured by heat, a part of it may never¬ 
theless be washed in this form by rain too far down and escape 
consumption through the roots, particularly in countries like 
Japan, where the temperature during summer is high and rains 
are copious and frequent. 
Organic materials applied as nitrogenous manures such as 
fishes, bones, oilcakes, brans, etc., are less soluble than either 
nitrates or ammoniacal salts. When mixed with the soil, they 
are first gradually decomposed by a multitude of minute fungi, 
yielding besides carbon dioxide and water, ammonia and similar 
bodies, which at their origin, are absorbed by the soil and 
likewise .converted in the course of time into nitric acid. In 
this way they secure to the plants a constant flow of nitrogenous 
food, the rapidity of which depends, of course, as well on the 
facility with which the materials are dissolved or softened and 
decomposed, as on climatic conditions, especially heat and moist¬ 
ure. The losses caused by copious rains are with organic 
manures less than with either nitrates or ammonia. 
Of the climatic conditions, heat and rain have, as already 
stated, a considerable influence on the effect of nitrogenous 
manures, as on the one hand they accelerate decomposition and 
nitrification in the soil, and on the other, may cause losses by 
washing away soluble substances. The experience gathered in 
central and western Europe as to the preparation, application, 
and rapidity of action of fertilizers is therefore not directly 
applicable to countries with considerably higher temperatures 
and copious rainfall. Considerations of this kind guided us in 
making in 1888 some experiments on the effect of various 
nitrogenous fertilizers, in the fields of this college. 
The soil on which these researches were carried out, consists 
of volcanic ashes mixed with some sand of fine grains of a 
smaller diameter than 1 millimetre. It is very light and porous, 
but retains the moisture very well, and is rich in humus and 
