AGRICULTURAL NATURE STUDY OUTLINES 
71 
VI. CLASSES OF SOIL 
By PROFESSOR C. F. SHAW 
Soil. —The soil is a mass of finely ground and altered rock material mixed 
with a small amount of decaying organic material (or humus). Rocks are 
chipped and broken by alternating heating and cooling, are worn away or 
dissolved by water and are worn and altered by air. 
Sedentary Soils are those in which the material has not been moved or 
transported from the place where it was formed. 
Residual Soils are sedentary soils formed by the accumulation of soil 
material through the decay and pulverization of rocks. Residual soils in 
many ways resemble the rocks from which they are formed. 
Cumulose Soils are sedentary soils that are formed by the accumulation 
of decayed plant remains. Peat and muck are those most commonly found. 
Transported Soils are those in which the soil material has been carried 
some distance from its origin and deposited in a new location. 
Alluvial Soils are those that have been moved and deposited by water. 
Physical Character of Soils 
- Sand. — Sand is loose and granular. The individual grains can readily be seen 
or felt. Squeezed in the hand when dry, it falls apart when the pressure 
is released. Squeezed when moist it will form a cast, but will crumble 
when touched. 
Sands are classified as coarse, medium, fine or very fine sands, depending 
on the size of the grains that compose them. 
Sandy Loam. —A sandy loam is a soil containing much sand but which has 
enough silt and clay to make it somewhat coherent. It has a gritty feel, 
and the sand grains can readily be seen. Squeezed when dry, it forms a 
cast which can be easily broken, but if squeezed when moist, a cast is 
formed that can be handled carefully without breaking. 
Sandy loams are classed as coarse, medium, fine or very fine sandy 
loams, depending on the size of the grains that compose them. 
Loam. —A loam is a soil having an even mixture of the different size grades 
of sand and of silt and clay. It is soft and mellow with a somewhat 
gritty feel, yet fairly smooth and rather plastic. Squeezed when dry, it 
forms a cast that will bear handling, while the moist cast can be handled 
very roughly without breaking. 
Silt Loam . — A . silt loam is a soil having little sand and only a small amount 
of clay, over half of the grains being of the size called “Silt.” It may 
appear quite cloddy but the lumps can be readily broken, and when 
pulverized it feels soft and floury. Either dry or moist it will form casts 
that can be freely handled without breaking. 
Clay Loam.—A clay loam soil in the field is dense 'and compact and breaks 
into clods or lumps. These are hard to break when dry, but when moist 
can be pinched between the thumb and finger to form a thin ribbon. The 
moist soil is plastic and does not crumble readily. 
