Soil Cr 



i\alion Service 



A soil scientist deteriniiiing texture 

 ill process of making a soil survey. 



not stick together, a sandy soil is 

 easily tilled. The large pores between 

 (he sand grains permit the rapid 

 downward movement of water hut 

 provide little opportunity for the soil 

 to hold enough moisture for the use 

 of plants. Hence, such soils dry out 

 quickly and can be tilled early in the 

 spring, but they are very droughty. 

 A soil in which the very fine particles 

 predominate so thoroughly that they 

 completely outweigh the effects of any 

 silt or sand present, is called a clay 

 soil. Such a soil is difficult to work 

 and forms clods if plowed when too 

 wet or too dry. The small pores in 

 clay soils will not transmit water 

 readily, and for this reason, these fine 

 textured soils are frequently not well 

 drained. The fine particles hold a 

 great deal of moisture for plant 

 use, but if too much water is present, 

 the water crowds out the air which 

 is just as important as water for 

 plant growth, 



A loam soil is one in which sand, silt, and clay occur in such pro- 

 portions that each has an equal influence on the character of the soil, with 

 no one predominating. So it can be said that the word loam means a 

 mixture. If the effects of sand, silt, and clay are evident, but one of them 

 predominates, the name of that size class is added to the word loam in 

 making the textural name of the soil. We have sandy loams where sand is 

 the main constituent, silt loams where silt predominates, or clay loams 

 where the clay has the greater influence on the properties of the mixture. 



Inside these broad classes of soil there are finer distinctions which are 

 recognized on the soil maps. A soil composed mainly of sand is called a 

 sand, but the presence of some silt and clay is recognized by calling it a 

 loamy sand. Since the sand grains vary somewhat in size, a further break- 

 down is made in the names of the soils. For example, we may have coarse 

 sand, or fine sandy loam, or even very fine sandv loam. 



In New Hampshire, no surface soil contains enough clay to be classified 

 as a clay soil. The nearest approach to a clay soil is one which is high 

 in both silt and clay and is called a silty clay loam. If the soils in the State 

 were arranged in the order of decreasing amounts and sizes of sand and 

 increasing amounts of silt and clay, a representative list would be as follows: 

 sand; loamy sand; sandy loam; fine sandy loam; silt loam; silty clay loam. 



Taken in the above order, there is a general decrease in the ease of 

 tillage, a decrease in the ease of water movement and root penetration, and 

 an increase in the ability of the soil to hold available water and plant 

 nutrients. Unless proper steps are taken to maintain it, humus will burn 

 out and disappear faster from the sandy soils than from the silt loams 

 or silty clay loams. Quite a large part of the soils in New Hampshire con- 

 sist of fine sandy loams, very fine sandy loams, and loams. 



