CHAPTER VI 



THE PROPERTIES OF SOILS 



Some advise to mix together earths of different qualities; for example, 

 light with heavy, and heavy with light ; fat with lean, and lean with fat ; in 

 like manner, red and white, and whatever has contrary qualities. Because this 

 mixture not only supplies what is wanting but also renders the soil with which 

 another is mixed more powerful, so that what is worn out, being mixed with 

 a fertile kind of earth, begins again to carry crops as if renewed, and what is 

 naturally barren, as clay, if mixed with another, in some measure serves in the 

 place of manure. THEOPHRASTUS 



60. Soil texture. The term soil texture refers to the size of 

 the particles of which soil is composed. Most soils consist of 

 particles varying in size from coarse to fine, although some soils 

 contain only coarse, and others only fine, particles. The coarse 

 particles are called fine gravel or coarse sand, and the next finer, 

 medium sand ; then follow fine sand, very fine sand, silt, and 

 finally clay. The relative amounts of these different grades vary 

 widely in different soils. A soil of coarse texture is one in 

 which the coarser particles predominate ; a soil of fine texture 

 is one in which the fine particles predominate (Fig. 30). 



Soils containing a large proportion of sand are also called 

 sandy soils ; those containing a large proportion of clay are called 

 clay soils ; those which are intermediate, between coarse and 

 fine, are called loam soils. A loam soil with a slight excess of 

 clay is called a clay loam ; a loam soil containing much silt is 

 called a silt loam. Various other names are applied to soils of 

 different textures, such as coarse sandy loam, fine sandy loam, 



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