formed under naturally well-drained conditions, while some are waterlogged 

 all of the time. Since these and other conditions may occur in varying 

 combinations, many different kinds of soil can be recognized, classified, 

 and mapped. For more than 50 years, the U. S. Department of Agriculture 

 and the State Agricultural Experiment Stations have been making surveys 

 in which the different soils are classified, named, and mapped. 



Soil surveys have been made and published for six counties in New 

 Hampshire within recent years. ^ These soil surveys were published on 

 scales of either one mile on the ground equals one inch on the map or two 

 miles on the ground equals one inch on the map. 



More recently, in connection with the work of Soil Conservation Dis- 

 tricts, more than 1,000,000 acres have been mapped on aerial photographs 

 with a scale of one mile on the land equals four inches on the photograph. 

 At present this mapping has covered more than 4,500 farms and is still 

 in progress. So far it has been conducted mainly on farm lands with little 

 work in the large forested areas. With the larger scale and the photographic 

 base, it is possible to outline areas as small as two or three acres and 

 show the locations of each area in relation to field boundaries. None of 

 these maps has been published, but they are available for inspection in 

 the local offices of the Soil Conservation Service and the New Hampshire 

 Agricultural Experiment Station, which are working jointly on the National 

 Cooperative Soil Survey.^ 



Characteristics 



Texture 



One of the principal characteristics of soil and one of the easiest to 

 identify is texture ^ the relative sizes of the soil particles. H we exclude 

 gravel and boulders, the soil particles may be divided roughly inio three 

 classes according to size. These are called sand, silt, and clay. Sand particles 

 are ones that feel gritty when rubbed between the fingers, and they possess 

 little power to stick together. The pore spaces between the sand particles 

 are usually large and continuous. Clay particles, on the other hand, are so 

 small that they can't be seen without a microscope. When moist, clay is 

 sticky, but when dry, it is usually stuck together into hard lumps. The 

 pore spaces between the clay particles are very small and frequently are 

 blind pockets. Silt particles are between sand and clay in size and in their 

 other properties. Dry silt feels like flour when rubbed between the fingers. 

 When moist, silt is somewhat slick or slippery but not very sticky. 



A soil consists of sand, silt, and clay in varying proportions. For this 

 reason the terms "sand", "silt", and "clay" are used not only to classify 

 the particles but also in making up the soil name. A soil composed mainly 

 of sand particles is said to have a sand texture. Since the sand particles do 



1 Soil survey reports and maps are available for Grafton County, published in 

 1939; Coos County. 1943; Strafford County, 1949; Cheshire and Sullivan Counties, 

 published together as one report, 1949; and Hillsborough County, 1953. An early sur- 

 vey of Merrimack County was published in 1906 and is out of print and not available, 

 except in some libraries. The survey of Rockingham County is rapidly approaching com- 

 pletion. County soil surveys are in progress in Belknap and Carroll Counties, and 

 Merrimack County is being re-surveyed. 



- For a complete list of the soils mapped, refer to Appendix A, page 80. 



