THE MAOAZiNK 
OF 
TBG 5GB00L OF SGRICULTURG, 
COLOMBO. 
Added as a Supplement monthhi to the “ TBOPICAL AGRICULTURIST’’ 
The following pages include tte contents of the Magazine of "'he Schod f 
Agricu I ture for September :~ 
i ‘"SB"' ■ NTTT?,TFTCATT ON. 
N the year 1877 Schloesiiig and 
Miintz gavej^to the world the 
results of their interesting ex- 
periments which went to prove 
that the conversion of nitrogen 
found in the soil in an inorganic_,form as ammonia, 
and in an organic form as decayed vegetable mat- 
ter, into nitrates was effected by the agency of a 
living ferment. AVhile these experiments have 
been verified by the English chemists, Warrington 
and Munro, no further light has been thrown on 
the nature of this germ since the continental 
chemists made their discovery concerning the 
minute organism which they considered assign- 
able to the family of bacteria, though much inter- 
esting information has been gained as to the con- 
ditions under whieh the nitrifying germ works. 
It is well known that different forms of nitro- 
genous substances applied to the soil act at 
different rates. Nitrate of soda acts more quickly 
than sulphate of ammonia ; sulphate of ammonia 
than the nitrogen in guano, bone-dust, dried 
blood, &c. But what is the exi^lanation of this 
difference in the rate of action of manures as 
plant food? Plants absorb the nitrogen they 
take as food from the soil in the form of nitrates, 
and in tlie first-mentioned manure the nitrogeir 
is of course in this form. In the second the 
nitrogen exists as ammonia, wliich has first to 
bo converted into nitrate before it becomes avail- 
able as plant-food, and time is required for this 
conversion. The production of nitrates either 
from ammonia or from organic nitrogen iSj by 
the agency of the minute bacteria, whose impor- 
tance was, as mentioned, only discovered in 1877. 
Till that year the production of nitrates in the soil 
was believed to have been brought about by a 
simple process of oxidation. The following ex- 
periment supplies the grounds for belief in the 
existence of the nitrifying germ as the cause 
of nitrification. If we take a dilute solution of 
ammonia, containing other plant food, and 
sterelize this solution, i.e., kill any living germs 
that it may contain by submitting it to a high 
temperature for a lengthened period of time, 
we will find that such a solution will keep for 
any length of time without showing, on being 
chemically tested, any traces of nitric acid. 
Introduce, however, a very small portion of fresh 
soil, and nitrification will at once set in. 
By experiment also it has been found that 
the nitrifying organisms are almost entirely 
limited to the surface soil, and that they ai-e not 
uniformly much below a depth of 9 inches. 
They may, however, exist at a greater depth, 
but when they do so, they are found in a very 
feeble condition. Even in the surface soil their 
distribution depends on the nature of the soil, 
for the presence of these bacteria is favoured 
by certain conditions wliich may obtain to a 
greater or less extent in different soils. For one 
thing they require a large amoimt of oxygen 
and hence it is only in the surface soil that their 
