December i, 1891] THE TROPICAL AGRICULTURIST. 
42 s 
that nitrogen is one of the first elements in the soil 
to be used up; that, of all the fertilizing elements, 
nitrogen is and always has been the most expensive. 
THE BPECIPIC ACTION 01' KITUOGEN UPON PLANTS. 
47. The influence of nitrogen in its various formf? 
upon plant growth is shown hy at least three strik- 
ing effects. _ 
First.— The growth of stems and leaves is greatly 
promoted, while that of buds and flowers is retarded. 
Ordinarily, most plants, at a certain period of growth, 
cease to produce new branches and foliage, or to in- 
crease those already formed, and commence to 
produce flowers and fruits, whereby the species may 
be perpetuated. If a plant is provided with as much 
available nitrogen as it can use just at the time it 
begins to flower, the formation of flowers may be 
checked, while the activity of growth is transferred 
back to and renewed in stems and leaves, which take 
on a new vigor and multiply with remarkable lux- 
uriance. Should flowers be produced under these 
circumstances, they are sterile and produce no seed. 
Second. — The effect of nitrogen upon plants is to 
deepen the color of the foliage, which is a sign of in- 
creased vegetative activity and health. 
Third.— The effect of nitrogen is to increase, in a 
very marked degree, the relative proportion of nitro- 
gen in the plant. 
LOSS or NITROGEN COMPOUNDS. 
45. Since ammonia compoiuids and nitrates dis- 
solve easily in water, is there not danger of their 
being carried away in drainage water from the upper 
soil out of reach of the plant ? 
Experiments have been made to settle the question, 
and results indicate that ammonia compounds are 
largely retained in the soil. Nitrates are apt to be 
washed out and lost in the case of bare fallow land; 
but when the soil is covered with vegetation there is 
little or no loss, for the reason that the roots of growing 
plants absorb nitrogen very readily. Some nitrogen is 
also lost by organic matter in the process of decay, 
escaping into the air as free nitrogen. 
These losses of nitrogen are, to some extent, 
replaced naturally by means of the nitric acid and 
ammonia dissolved by the rain and dew, also by 
organic matter decaying at the surface of the soil, 
and also by conversion of the free nitrogen of 
the air into some form which the plant can take up 
and use. These natural additions of nitrogen do 
not usually make good on the farm the losses, and 
in time the nitrogen becomes insufficient to produce 
paying crops without the addition of nitrogenous 
manures. 
We shall notice later the various forms of nitrogen 
ordinarly used in commercial fertilizers. — Bulletin 
of the New Yorrh Agricxitwral Experiment Station: 
SOME POINTS IN PEACTICAL FORESTRY. 
In an interesting review, by Dr. Brandis, of Dr. 
Schlich's " Manual of Forestry," published in a recent 
number of Nature, attention is called to the fact that 
this book was prepared by the author primarily for 
the use of the students at the Cooper's Hill Forest 
School in England. That school was established seven 
years ago, in connection with the Eoyal Indian En- 
gineering College, in order to give the needed pro- 
fessional training to young Englishmen who desired 
to enter the Indian Forest Department. When the 
first volume of this handbook appeared some persons, 
who took a deep interest in the progress of forestry 
in the British Indian Empire, were surprised that it 
did not deal with Indian trees, but that its teaching 
were illustrated by the Oak, the Beech, the Scotch 
Pino and other trees of Europe, and the book was, 
therefore, pronounced by them a failrae. But the 
principles of silviculture are the same everywhere, and 
the application of these principles to the treatment of 
different woods in different parts of the globe will 
lead to tho adoption of similar methods; and, there- 
fore, according to Dr. Brandis, tho author of tbf | 
manual was right in selecting the timber I 
5i 
Europe to illustrate these principles and the prac- 
tice based upon them, because these trees are at 
hand for example, and because the systematic treat- 
ment of European forests is of long standing, and 
has endured the test of experience, while the metho- 
dical care of Indian forests is not more than thirty- 
five years old. As an interesting example of the way 
in which similar practices have developed in the 
rearing and tending of woods in Europe and in 
India, we quote the following parallel from Dr. Brandis' 
review : — 
In a loop of the Main River, in Lower Franconia, 
east of Asohaffenburg, rises an extensive mountainous 
country, clothed with almost unbroken forest of singular 
beauty and of enormous value. It is the Spessart, in 
old times knovra as the home and haunt of great high- 
way robbers, but also knovra from time immemorial 
as the home of the best Oak timber in Germany. The 
red sandstone of the Trias, which everywhere is the 
underlying rock in this extensive forest-country, makes 
a light sandy loam, which, where deep, is capable of 
producing tall, cylindrical, well-shaped stems. Having 
grovTO up, while young, in a densely crowded wood, 
the Oak here has cleared itself of side branches at an 
early age. Hence these clean straight stems 
which, in the case of Spruc«, Silver Fir, and other 
forest-trees, may justly be said to be the rule, but 
which the Oak does not produce, save under these and 
similarly favourable circumstances. The species here 
is Quercus sessi72';?ora; this species does not form pure 
forests, but is always found mixed with other treeg, 
the Hornbeam, the Beech, and on the lower slopes 
of the western Schwarzwald, the Silver Fir. In the 
Spessart, the Beech is associated with the Oak in the 
same manner as the Bamboo is the chief associate 
of the Teak-tree in Burma. 
The principles which guide the forester in the pro- 
per treatment of his woods are the same in India as 
in Europe. In the Teak-forests of Biu'ma the Bamboo 
has a position similar to that of the Beech in the 
Oak-forests of the Spessart. Oak and Teak are both 
trees with comparatively light foliage. Pure woods 
of these species, while young, are sufficiently dense 
to shade the ground, whereas at an advanced age the 
wood gets thin, the canopy light, and the result is 
that grass and weeds appear, and that by the action 
of sun and wind the soil hardens and is less fertile 
than the loose porous soil, which is shaded by dense 
masses of foliage. Hence the advantage of associates, 
which, like the Beech in Europe and the Bamboo in 
Burma, shade the ground with their dense foliage, 
and enrich it by the abundant fall of their leaves. 
But it is not only the condition of the ground which is 
improved by these useful associates. Teak and Oak 
have this specialty also in common, that, when grow- 
ing up alone, their stems, instead of running up into 
clean cylindrical boles, are apt to throw out side 
branches, which greatly impair the market value of 
the log. But when growing up in dense masses with 
their natural associates, these latter, crowding in aa 
they do on all sides around the Oak in the Spessart 
and the Teak in Biu-ma, prevent the development of 
side branches, and thus produce clean and regularly 
shaped stems. 
In these and many other ways are the associates 
of the Teak and of the Oak useful friends, so to speak. 
Under certain circumstances, however, and at certain 
periods of their life, they are clftngerous enemies to 
their more valuable companionil. On the sandstone 
of the Spessart, and elsewhere, the Beech, as a rule, 
has a more vigorous growth than the Oak ; it gets 
the upper hand, and, unless it is cut back or thinned 
out in time, the Oak, if both are growing up in an 
even mixture, has no chance. The Bamooo is even 
more formidable as an enemy of the young Tp«*- 
tree. Though the Teak may have had a lon^,''''*'?' 
if a crop of Bamboos— either the shootf °}9 
zomes, or, perhaps, the result of „^®t""^g 
the old Baf boo-Forest, cIwbngirih^TlTifdoomed 
As st'n a's tyji' °' the^Bamboo have acqnbed 
^ifficie^ -'^Stli, they produce, within a few vveeks, 
^■■^-o tne rains, such a pvofusion of full-sized shoots 
say twenty to tlnrly feet high, that the yoimg Teak- 
trees ftmpng them arc throttlegl and estjugiushed. 
