Nitrates in the: Soii*. 7 
distributed throughout the cultivated sections of the State. The 
brown streaks often seen around the edge of a wet place in some 
lawns, or along the margins of an irrigation furrow, are in very 
many instances due to the same cause. The writer has found very 
marked examples of this on the College farm this season, and has 
seen it occurring abundantly in other parts of the State. 
Many people imagine that this black alkali is brought to the 
surface by water rising from below, such is not the fact as follows 
from the consideration of the general distribution of this same color 
in places where there is no rising water plane, others think that it 
is alkali dissolved out of other lands and brought into these places 
by seepage water, but this notion is refuted by the occurrence of 
just such brown spots on mesas which are themselves the highest 
cultivated lands in the section. 
The most of us think of the soil as a mass of very small parti¬ 
cles of rocks and some moisture which furnishes physical support 
and sustenance to the plants that grow in it, and nothing more. We 
do not think of it as teeming with life, but it is. Some of this life 
is beneficial to the growth of f the cultural plants which furnish us 
our food and pleasure, but some of it is indifferent or perhaps pre¬ 
judicial. Most of us have, during the past few years, heard of the 
part played by certain germs, which acting in succession effect the 
conversion of organic nitrogen, vegetable or animal, into nitric acid 
forming nitrates in the soil, in which form the nitrogen is taken up 
by the plants. This change of organic nitrogen, either of vegetable 
or animal origin, into nitric acid or nitrates, is called nitrification, 
and consists, as intimated, of several separate processes. This is 
not the only process going on in the soil which is dependent upon 
the presence of germ life, or micro-organisms. Among others is 
one which has to do with the building up of nitric acid or the forma¬ 
tion of nitrates. The preceding process, nitrification, depends upon 
the vegetable or animal matter in the soil for its suoplv of nitrogen 
and there are three steps in the process of converting it into nitric 
acid, but in this one the source of the nitrogen is the atmosphere and 
the agent which takes the nitrogen from the atmosphere and con¬ 
verts it into nitric acid, respectively nitrates, is also a germ that 
lives in the soil. There is a number of species of this germ, one of 
which produces a brown pigment. This germ is abundant in our 
soils and apparently grows with great luxuriance. The brown color, 
whether in spots in a field or on the side of an irrigation furrow, or 
as a broad zone about the edge of a moist spot, is of itself not in¬ 
jurious but it is usually conclusive testimony of the presence of this 
germ, and a sample of soil taken from such a place will readily 
react for nitric acid. These germs are not necessarily detrimental 
to our trees and crops. If they would produce only just enough 
