July 15,1924 
Chemical Examination o f Peat Materials 
71 
At this time only a few of the prin¬ 
cipal groups of plant products can be 
considered, and but a few examples of 
the chief kinds of peat material have 
been examined. This new matter, 
however, offers a basis for reviewing the 
results of some of the more recent peat 
investigations made by various workers. 
Although the aims of sectional workers 
are divergent, their contributions are 
necessarily interdependent. Tenta¬ 
tively these and the results of the pres¬ 
ent series of analyses are summarized 
and discussed in relation to (1) nitrog¬ 
enous substances in various types of 
peat; (2) nonnitrogenous substances, 
including crude fiber and nitrogen-free 
extract; (3) ether-alcohol extract; and 
(4) mineral matter. 
The search for new facts concerning 
the physical, chemical, and bacteriologi¬ 
cal qualities of the various layers of 
peat should take into account all the 
basic facts and conclusions which are 
of importance to practical workers in 
peat land utilization. 
NITROGENOUS SUBSTANCES . IN 
DIFFERENT PEAT MATERIALS 
The nitrogenous substances in peat 
materials are of interest agriculturally 
and industrially in several ways. One 
to five per cent of organic nitrogen may 
be found in peat, but little of this is 
available as plant food. Jodidi (21), 
Stutzer (50), and others have shown 
that nitrates are not present in freshly 
dug peat materials. The quantity of 
nitrogen as ammonia is very small, 
ranging from a few thousandths to a 
few hundredths of 1 per cent of 
nitrogen. The water solubility of 
peat nitrogen varies within wide limits. 
More nitrogen can be extracted from a 
sample of peat in a finely divided state 
than from a coarse fibrous or woody 
type of material. Peat digested at 
higher temperature and pressure in an 
autoclave gives a larger amount of 
water-soluble nitrogen. The amounts 
and concentration of acid or alkaline re¬ 
agents, the duration of digestion, as 
well as other methods of manipulation 
in the laboratory have an influence 
upon the percentage of nitrogenous 
bodies that can be extracted from peat 
materials. The relative value of 
peat materials containing high amounts 
of these compounds depends on the 
means by which the nitrogenous sub¬ 
stances in peat layers can be ex¬ 
tracted by distillation and obtained as 
ammonia, or otherwise can be con¬ 
verted into an available source of plant 
food. It has long been known that a 
composting procedure of some kind 
must be adopted to make peat nitro¬ 
gen easily accessible either for crops 
grown upon peat land, or for plants 
grown on mineral soils to which peat 
is applied for the production of humus. 
The nitrogenous substances in peat 
materials are very complex, because 
in addition to the nitrogenous con¬ 
stituents of plants, bacteria, and 
molds, the layers of peat also contain 
the remains of animals of various kinds. 
On account of their great variety and 
complexity little more than a beginning 
has been made in determining the 
differences in the composition of nitro¬ 
genous bodies in organic materials. 
The extreme complexity and variety 
of the organic compounds in soils has 
been demonstrated mainly through 
the work of Schreiner and his collab¬ 
orators (45). Only recently, however, 
investigations have been undertaken 
upon the nature of these compounds in 
the different kinds of peat and upon 
the variations in the availability of 
their nitrogen. 
In peat the crude protein may con¬ 
sist of a large proportion of inert sub¬ 
stances of animal origin. A very consid¬ 
erable part of this fraction in sedimen¬ 
tary types of peat is frequently due 
to the admixture of chitinous com¬ 
pounds derived from certain seeds, 
fungi, insects, the egg cases and skeletal 
portions of various crustaceous, and 
other forms of plankton life. Birge 
and Juday (8, p. 81) report that crude 
fiber derived from plankton Crustacea 
yielded 5.9 to 6.2 per cent of nitrogen. 
This material is relatively unhydrolyz- 
able and has a low decomposition value. 
In air-dried peat materials, the crude 
protein constitutes from 2.75 per cent 
to 19.63 per cent of the organic matter 
(Table I). The results show clearly 
that the range of variation is largest in 
the fibrous group of peat materials. 
Sphagnum peats yield the smallest per¬ 
centage, varying from a little more 
than 2 to about 4.5 per cent. In com¬ 
parison with these the sedge and reed 
peats yielded over 11 to 19.63 per cent. 
On the other hand, woody and sedi¬ 
mentary types of peat average only 
about 11 per cent. 
Table II shows the variations in 
crude protein when stated on a mois¬ 
ture and ash-free basis. The maxi¬ 
mum of 30.15 per cent is found in 
the gelatinous peat from Fremont, 
Ind., and the minimum percentage in 
the sphagnum peats from Culver, 
Minn., Fairbanks, Alaska, and Calais, 
Me. Peats of the sedge, reed, and 
woody types contain from 12 to 24 
per cent of crude protein. Taken as 
a whole, the results show distinct dif- 
