July 15, 1924 
Chemical Examination o f Peat Materials 
77 
Crop production on peat deposits is 
dependent on processes leading to the 
decomposition of carbonaceous ma¬ 
terials. Hence, the biological phenom¬ 
ena which transfer cellulose to soluble 
compounds are obviously of fundamen¬ 
tal importance. But investigations 
upon quality and quantity of available 
•carbonaceous compounds in different 
types of peat are still problematical. 
It is certain that bacteria as well as 
fungi are present in definite horizons of 
peat deposits, and that both act differ¬ 
ently in the several kinds of peat. 
Microorganisms which make use di¬ 
rectly of cellulose or live on its decom¬ 
position products may depress or favor 
the accumulation of nitrogen to a 
marked degree. An accurate knowl¬ 
edge of the biochemical value of the 
various layers of peat from differ¬ 
ent depths and stages of decomposition, 
and the soluble products formed from 
them under water-logged conditions 
and during soil-forming processes, is of 
great practical value. The rapidity 
with which the cellulose component be¬ 
comes decomposed may indicate the 
differences in the fertility of peat land. 
The investigations undertaken by Kel- 
lerman and his collaborators {22, 29) on 
the destruction of cellulose by bacteria 
and filamentous fungi have done much 
to stimulate this phase of the peat 
problem. The work of Lohnis and his 
students {26, 28, 41 ) to determine the 
nutritive value of peat humus for 
Azotobacter, the studies of Hutchinson 
and Clayton ( 20 ), Christensen (5) and 
others, have demonstrated the wide¬ 
spread occurrence of cellulose-destroy¬ 
ing bacteria and that they usually act 
symbiotically, utilizing probably inter¬ 
mediate products. It would be desira¬ 
ble in this connection to ascertain more 
accurately the degree of utilization of 
specific peat materials by different bac¬ 
teria and fungi. Based on observations 
made in the field, certain fungi are unique 
in the way their mycelium incloses com¬ 
pletely portions of fibrous or woody 
layers of peat at depths from 2 to 4 feet 
below the surface, and form clusters of 
fruiting bodies in the space formerly 
occupied by the peat material. No 
reference covering these observations 
has been found in the literature. 
In view of the fact that the present 
•classification of carbonaceous sub¬ 
stances in peat materials includes inter¬ 
mediate products of decomposition in 
the nitrogen-free extract, it is important 
to determine the amount and the 
distribution of this fraction in different 
layers of peat. 
The nitrogen-free extract, as given 
in Tables I and II, composes all carbo¬ 
naceous residues free from fiber, crude 
protein, fatty substances and ash. The 
quantity of this fraction is determined 
by difference. The nitrogen-free ex¬ 
tract embraces a great variety of 
soluble organic substances. In the 
analyses of crops and feeding stuffs this 
fraction represents the starches, sugars, 
pentoses, nonnitrogenous acids and 
similar compounds, including gluco- 
sides, pectins, and tannins. It is un¬ 
fortunate that for this group of sub¬ 
stances at present peat investigators 
must rely upon figures obtained “by 
difference.” The extent of the analyti¬ 
cal error as well as the actual composi¬ 
tion of this fraction in the different 
types of peat remain unknown. 
The analyses in Table I show that 
the nitrogen-free extract in air-dry peat 
materials varies from 9.81 per cent, in 
the Fremont, Ind., gelatinous peat, to 
54.94 per cent in the heath-shrub peat 
with fibrous sedge admixture obtained 
from Charlevoix, Mich. Most samples 
contain 30 to 40 per cent. The two 
samples from the Florida Everglades 
show a relatively low percentage, 
approximately 27.8 per cent. The 
small proportion of nitrogen-free ex¬ 
tract in the Florida fibrous sedge peat, 
and in certain other peat samples, is 
doubtless to be explained by the loss of 
dispersed and colloid organic material 
in the progressive leaching character¬ 
istic of humid regions. Calculated on a 
moisture and ash-free basis this frac¬ 
tion of organic matter ranges from a 
minimum of about 30.71 per cent in the 
colloidal peat from Fremont, Ind., and 
of 34.91 per cent in the leached fibrous 
peat from Florida, to a maximum of 
66.24 per cent in the hypnum peat from 
Phillips, Wis. In the majority of peat 
samples, however, it amounts to 40 and 
50 per cent. Again the quantity of the 
nitrogen-free extract exhibits a ten¬ 
dency to vary not with depth below the 
surface, but with the composition of the 
plant remains and their relative stage 
in chemical alteration. As shown in 
Tables I and II, the more decomposed 
reed, sedge, and sphagnum types of 
peat, irrespective of their age or posi¬ 
tion in the profile of a deposit, yield 
more than 50 per cent of sub¬ 
stances classed as nitrogen-free ex¬ 
tract, though some of the component 
materials are undoubtedly lost by 
leaching. Coarsely fibrous sedge and 
sphagnum peat contain much less of 
this fraction. Woody and sedimen¬ 
tary peat material, high in fiber, also 
supply only moderate amounts. The 
results suggest strongly that the state 
of decomposition does not run parallel 
to the depth at which a peat material 
is found below the surface, but that 
an approximate correlation exists be- 
