SOIL 33 



Animals, too, like the gopher and woodchuck, burrow 

 into the earth and help to tear up and break down 

 the rock. When they die their bodies decay and be- 

 come a part of the soil. Earthworms, or "angle- 

 worms" as they are called, feed on the soil and break 

 up the particles into still finer ones. 



Agencies of Soil Formation. These are the agen- 

 cies, then, that assist each other in the formation of 

 soil : Glaciers, wind, water, frost, plants, animals, and 

 gases in the air. 



Kinds of Soils. What kinds of soils are formed by 

 all these agencies? It must be remembered that all 

 soil originally came from the rock, and the kind of 

 soil must therefore depend on the kind of rock from 

 which it was made. That is, we have sandy soil in 

 sandstone regions, and in limestone regions clay is 

 usually found. Some black soil, found on low land, 

 is made principally from decayed leaves and plants. 

 This soil is called humus. Humus mixed with clay 

 and sand is called loam. If there is more sand than 

 clay in the mixture it is called sandy loam, and if there 

 is more clay than sand in the mixture it is called clayey 

 loam.* 



The Treatment of Soils. Of course, these soils are 

 found mixed in every possible proportion. This fact 

 leads to a great variety of soils, and it is the farmer's 

 business to learn the nature of the soil on his farm and 

 how best to handle it. Loamy soils are the best farm 

 lands, because of the ease with which they may be 

 cultivated. They are warm soils and hold moisture 



* The kind of soil is determined by the relative amounts of 

 large and small soil particles. 



