UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 802 



Contribation from the Bureaa 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-FertiUty 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 Irt 



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 dijfferent agricultural and technical possi- 



132927°— 19— Bull. 802 1 



