SOIL AIR 101 



59. The Kinds of Productive Soil. For farming we do 

 not want the soil to contain much stone or gravel, nor do 

 we want pure sand or pure clay. We want a mixture of 

 sand, silt and clay, with some humus. Such a soil is called 

 loamy. All productive soils are usually loamy. 



Loam is a soil that is intermediate between sand and 

 clay. It is not so open and porous as sand, or so stiff 

 and tenacious as clay. That is, it is a mixture of sand, 



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STUDYING SOILS. 

 Students using the soil auger to get samples of soils. 



silt, and clay, together with some humus and of course 

 with air and moisture. The major portion is silt. A 

 sandy loam contains more sand than clay ; a clay loam, 

 more clay than sand. For general farm purposes a medium 

 or average loam is preferred, especially if it contains a 

 large amount of humus. 



60. Soil Air. The spaces between soil particles are 

 occupied either by air or water. Both are necessary for 

 plant roots. If we completely submerge ,the roots of a 

 potted plant in a pail of water, the plant soon turns yel- 



