UNITED STATES DEPARTMENT OF AGRICULTURE 
jg\j9*^Lru 
BULLETIN No. 802 
Contribution from the Bureau of Plant Industry 
WM. A. TAYLOR, Chief 
Washington, D. C. 
PROFESSIONAL PAPER 
December 29, 1919 
QUALITY AND VALUE OF IMPORTANT TYPES OF 
PEAT MATERIAL. 
A CLASSIFICATION OF PEAT BASED UPON ITS BOTANI- 
CAL COMPOSITION AND PHYSICAL AND CHEMICAL 
CHARACTERISTICS. 
By Alfred P. Dachnowski, 
Physiologist, Soil- Fertility Investigations. 
CONTENTS. 
Page. 
The present status of peat utiliza- 
tion 1 
Definitions and points of view in 
classifying peat materials 9 
A tentative classification of im- 
portant types of peat materials 14 
The aquatic group of peat ma- 
terials . 14 
Macerated type ._ 16 
Colloidal type 22 
Doppleritic type 23 
The marsh group of peat mate- 
rials ^ 23 
Reed-grass type 26 
Sedge type 27 
Brown-moss type 28 
Page. 
A tentative classification of impor- 
tant types of peat materials — 
Continued. 
The bog group of peat ma- 
terials 29 
Bog-moss type 32 
Arrow-grass type 33 
Cotton-grass type 33" 
Bog-shrub type 34 
The swamp group of peat ma- 
terials 34 
Alder-willow type : 36 
. Birch type 36 
Deciduous-forest types 36 
Coniferous-forest types 37 
Literature cited 39 
THE PRESENT STATUS OF PEAT UTILIZATION. 
The problem of peat utilization may be analyzed from several 
points of view, but only a few aspects of the subject are of essential 
importance to emphasize at this time. Among the peat problems in 
question none, in the opinion of the writer, is so serious as the failure 
to realize the existence of the important grades or types of this mate- 
rial in regard to quality and their relative value for agriculture or 
other uses. 
There is a growing recognition of the fact that the term " peat " is 
too general to be applied to plant remains essentially different in 
composition, which have different agricultural and technical possi- 
132927°— 19— Bull. 802 1 
