MASSACHUSETTS PEAT LANDS 31 



as layers of plastic peat derived from aquatic plants or formed under 

 periods of flooded and high water conditions; layers of granular 

 material resulting from woody shrubs during periods of excessive 

 drought conditions or following drainage changes; whether dis- 

 tinctions in the materials arise on account of strata of windfallen 

 timber or of drifted impurities, such as ashes, silt, clay, or marl, the 

 amounts of which depend on the currents of streams and rivers, their 

 flooding power, etc.; whether plant growth and crop yield are 

 influenced by a hardpan of fine-grained organic material or by one 

 arising from compounds with lime or with iron; whether the contact 

 layers of peaty material with a bottom of sand, gravel, clay, diato- 

 maceous earth, or marl are continuous or not, and whether the 

 mineral soils below, or those along the margins of the peat land, 

 indicate predominantly solution and bleaching action or a deposi- 

 tion and "staining" process with mottled coloring, — ^ all these 

 points are of the greatest practical import. Marked physical 

 dift'erences arise from the several materials which undergo disinte- 

 gration, in the relative abundance of that indefinite, fine-grained 

 debris which plays the role in distinctions between heavy and light 

 peat lands and which gives a certain degree of adhesive plasticity, 

 but under some conditions render the surface peat soil almost 

 impervious to water, probably due to the absorption of air. 



The physical nature of the different peat and muck lands of the 

 state and their respective substrata materials are doubtless of the 

 widest practical importance, since it is in general more difficult 

 to change the nature of the vegetable mass than to remedy the 

 chemical deficiencies. Aside from the modifying influences of field 

 conditions this is probably one reason why a chemical analysis of an 

 organic soil is generally of little value in establishing relations to 

 crop productivity. It is necessary, therefore, at least in somewhat 

 more detail than undertaken hitherto, to understand the differences 

 in the respective groups of peat lands, the phases of their materials 

 and the field conditions under which they were formed. A profit- 

 able use of them can be made with related cultural methods and a 

 choice of suitable crops. How important a detailed investigation 

 may become to Massachusetts and for that matter to any other 

 state, in view of the existing great geographical differences in 

 climate, geology, and vegetational influences affecting the character 



