SECTION FOURTH. 



MECHANICAL CULTIVATION, 



CHAPTER I. 



THE MECHANICAL CHARACTER OF SOILS. 



The meclianical character of the soil has been 

 Bufficiently explained in the preceding remarks, and 

 the learner knows that it has many offices to perform 

 aside from the feedmg of plants, 



1. It admits the roots of plants, and holds them in 

 their position. 



2. By a sponge-like action, it holds water for the 

 uses of the plant. 



3. It absorbs moisture from the atmosphere to 

 supply the demands of the plants. 



4. It absorbs heat from the sun's rays to assist in 

 the processes of growth. 



4. It admits air to circulate among roots, and sup- 

 ply them with a part of their food, while the oxygen 



