few days or a few weeks, usually during the spring; (3) poorly drained soils 

 which are saturated to within a few inches of the surface for periods of _ 



several weeks or even months during each year; (4) and very poorly drained, I 



which are saturated to the surface most or all of the time. The last two 1 



conditions impose a very definite limitation on the use of the land. 



Color 



Color differences in soils are easily seen and are often used in soil 

 mapping. Actually soil color in itself is not important since it has little 

 if any effect on plant growth. It may, however, be the result of some im- 

 portant but obscure condition in the soil. 



Frequently the subsoil has a richer brown color than the surface soil, 

 which is an indication that the surface has been leached during the process 

 of soil formation. In the northern part of the State, and at higher elevations 

 in the southern part, this leaching has been great enough to form a light 

 grey or almost white layer just beneath the organic layer. This grey layer 

 is usually thin, and if the land has been plowed, the grey material has been 

 mixed with the soil beneath and the layer has disappeared. In some parts 

 of the State the soils have been formed from rock materials containing 

 oxidized iron to give a brown or reddish color to the soil. Although these 

 color conditions are quite easily seen, neither of them is now thought to be 

 highly important in affecting the use or treatment of the land in New Hamp- 

 .shire. 



Color is an important clue in recognizing natural drainage conditions. 

 Soils with impeded drainage usually have a darker surface than the well- 

 drained soils, because of the greater accumulation of humus. As a general 

 rule, the darker the surface soil, the poorer the drainage. Also, in the poorly 

 drained soils the subsoil color is usually mottled, with spots of brown, 

 yellow, or red intermixed with grey. The depth to this mottled condition 

 is important. The closer the mottling is to the surface, the poorer the 

 natural drainage condition of the soil. 



*&^ 



Effective Depth 



If the soil consists of a mantle only a foot or two thick over bedrock, 

 roots are limited in their depth of penetration and the shallow layer of 

 soil can hold only a limited amount of moisture and nutrients. As a result 

 the deep-rooted species of plants are not suited to such soils and plants 

 growing on shallow soils will suffer from a lack of water and nutrients. 

 If the surface of the bedrock is a level plane or in the form of a basin, the 

 rock will hold water which seeps down to it so that the soil above it is 

 saturated for a part or all of the year. On a sloping surface, water which 

 accumulates on top of the rock may seep down the slope and come to the 

 surface at some lower place, causing a wet spot in the field. 



Somewhat the same results may develop if a dense or compact layer 

 of soil material occurs near the surface. The severity of the undesirable re- 

 sults depends on the degree of compaction. Some such layers may slow 

 the movement of water without stopping it entirely so the results are less 

 injurious. In fact, there is evidence that in some cases the result of a com- 

 pact subsoil may be beneficial. Under a sandy, open topsoil which holds 

 very little moisture, such a compact layer may increase the amount of 

 water that is held within reach of the plant roots. 



