IMPORTANT TYPES OF PEAT MATEPJAL, 5 



saline impurities and in acid, alkaline, or neutral reaction. Some of 

 these rock fonnations yield marked amounts of soluble injurious salts. 



Special climatic conditions influence appreciably the disinte- 

 gration of peat nuxterials, the formation of organic colloidal debris, 

 and the direction of movement or transport of dissohed mineral 

 constituents (8). The reactions may lower the supply and concen- 

 tration of nearly all available essential plant-food constituents and 

 thus effect malnutrition, a prevalence of plant diseases, and allow 

 certain plants and microorganisms to outgrow others, or they may 

 lead to local accumulations of salts at the surface of the peat deposit 

 or at the margins and in the mineral substratum underneath i>eat 

 accumulations. Cultural practices and drainage systems in no small 

 measure may favor and accentuate both the contamination through 

 the movement of undergi^ound waters or springs in peat materials 

 with high decay capacity and the concentration of salts by seepage or 

 by evaporation. More consequential still are the effects of a pro- 

 nounced inland or a tj'pical oceanic climate on the disintegration, 

 absorption, deposition, and leaching phenomena. Aside from the 

 presence of either an abundance or a deficiency of agriculturally de- 

 sirable mineral constituents, the climatic contrasts give rise to classes 

 of peat land which resemble closely the " Tschernosem " and the 

 " Podsol " condition featured by foreign writers (11). 



It is obvious, therefore, that those inquiries are likely to be most 

 fruitful which are concentrated first of all on the fundamental prob- 

 lem of determining and characterizing the types of peat material 

 which are representative of distinct regional divisions or geographic 

 areas of the United States and reserve for later discussion the details 

 of the structure and contents of special peat deposits which are con- 

 sidered to be either with or without great value or are selected as 

 representative peat deposits for specific experimental or industrial 

 purposes. 



It seems to the writer eminently desirable at this time to give con- 

 sideration especially to those chief types of peat material in this 

 country which are characteristic of peat deposits in European coun- 

 tries; to emphasize mainly the grades or types which resemble or 

 coincide with each other and whose botanical composition is based 

 upon the remains of plants known to occur in Europe; and to 

 characterize those phases which are preserved conspicuously in a 

 similar stage of disintegration in this country, irrespective of their 

 positional relationship in the different layers of a peat deposit. They 

 alone demand consideration in the present state of our imperfect 

 knowledge, partly because through the recognition of these types 

 considerable progress can be made in the fixing of standards of qual- 

 ity and in securing their adoption; largely, however, because the 

 physical and chemical characteristics of these types have been sys- 



