Our New Hampshire Soils 



SEVERAL thousand years ago an ice sheet (glacier) crept down from the 

 north and covered the entire State. This great mass of ice, possibly a 

 mile in thickness, acted like a giant bulldozer and scraped the surface of 

 the ground, plucked boulders from the bare mountain sides and carried 

 this material to the south, crushing and mixing it as it went. Later, as 

 the ice melted, the rock material in the ice was dropped to form an irregular 

 blanket over the solid bedrock beneath. 



In places, the bedrock is now exposed and bare; in other places, it is 

 covered by a mantle ranging from a foot or two up to 40 or 50 feet i'n 

 depth. This mantle is a mixture of all sizes of fragments from the very 

 finest clays up to boulders as large as a house. 



This ice-deposited, non-stratified material, called glacial till, is the 

 source of soils over much of the State, but some of the material was re- 

 worked still further before it came to rest to form soil. The water from 

 the melting ice picked up some of the smaller particles and carried them on. 

 The varying velocities of streams and sheets of water sorted the material 

 according to the size of the particles and laid the coarser ones down in 

 beds of sand and gravel. The numerous sand and gravel pits in the State 

 provide obvious examples of the results of this action. In this bulletin, w^e 

 call this water-deposited, stratified material, glacial outwash and river ter- 

 races. 



The very fine particles of silt and clay were carried further bv the 

 water, finally coming to rest in the quiet waters of ponds, lakes, and arms 

 of the sea. These depressions became filled and the water receded, leaving 

 beds of silt and clay, in places with a thin layer of fine sand over them. 

 Many of the depressions were not completely filled with this type of ma- 

 terial as evidenced by the numerous ponds and lakes in the State today. In 

 a few cases, the water was shallow enough for plants to grow and as they 

 died and fell, their remains accumulated to form deposits of muck and peat. 



Even after the ice disappeared and the soil-forming processes started, 

 there was some transportation of material by the post-glacial and present 

 day streams. Each of these present day streams is building its river bottom, 

 dropping material in some places and eroding it away in others. Much of 

 the river bottom material has been deposited so recently that there hasn't 

 been time for it to be as thoroughly acted on by the weather as the de- 

 posits which date back to the Ice Age. 



All of the soil-forming processes have not acted to the same extent or 

 in the same way on all of the soil materials. The ice and the water did 

 not lay the material down uniformly, but deposited some of it in knolls 

 and hollows. Some of the hollows held water: in other depressions, the 

 ground water table was close to the surface and the deposited material 

 was waterlogged for all or part of the year. Some of the knolls are so 

 gravelly and open that they hold practically no available water. The soils 

 of the State may therefore be divided into: (1) those formed under well- 

 drained conditions. ( 2 ) those formed under permanently waterlogged con- 

 ditions, and (3) those which are wet at times but dry at others. These 

 conditions affected the kind and intensity of the soil-forming process and 

 as a result the soils are quite different in character from place to place. 



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