65 



CHAPTER VL 



THE SOIL (CONTINUED), AND SOME OF ITS CON- 

 NECTIONS WITH THE PLANT. 



N.iture of mechanical improvement : mixing of sands and clay.§. 

 Evils of wetness in the soil. Beneficial effects of drains-, what 

 kind of drains best; proper depth; materials of which they 

 should be made ; the different varieties of tiles ; subsoil plough- 

 ing; trench ploughing. Connection between inorganic part of 

 the soil and of the plant illustrated. Plants seem to require 

 all of the inorganic substances in the soil, but not in the same 

 proportions. 



SECTION I. WHAT THE CONDITION OF THE SOIL SHOULD BE, 

 AND THE NATURE OF MECHANICAL IMPROVEMENT. 



We are now able to say that a fertile soil should 

 have all of the substances which were mentioned in 

 Table L, and were also named when giving the com- 

 position of the plant. These substances should be pre- 

 sent in abundance, and yet none of them in too large 

 quantity; they should be in forms best adapted to the 

 nourishment of plants, and the physical character of the 

 soil should be such that the plants could easL penetrate 

 in every direction with their roots to obtain tnem. Air 

 and warmth should also pervade every part, because 

 under their influence the plant flourishes better, and 

 the necessary changes in the composition of the soil 

 take place more readily. To bring about these con- 

 ditions is a study for the farmer, and the latter of them 

 come appropriately under our present head. 



By mechanical improvement of the soil, I mean the 

 improvement of its texture, and of its other qualities, 



