20. THE DIFFERENCE BETWEEN THE SURFACE S< )1L AND THE SUBSOIL 



The former is usually darker, having more humus, and usually richer. The subsoil, 

 however, is potential plant food; it gradually becon-.cs surface soil 



21. HOW PLANTS EAT 



The fringe of delicate root hairs may IK seen on many of these rootlets. The root hairs 



feed on the outside of particles of soil. Hence the finer 



a soil is the more feeding area it has 



