30. THE THREE CHIEF INGREDIENTS OF SOILS; ON LEFT, HUMUS OR 

 DECAYING VEGETATION; ON RIGHT, A LUMP OF 

 CLAY; IN MIDDLE, SAND 



These three are combined in nearly all farm soils in 

 varying proportions 



31. A CLAY SOIL CRACKING 



The soil may be cracked for some distance below the surface. Much soil 

 water is escaping through the cracks 



