SOILS AND MANURES 



CHAPTEE I 



INTRODUCTORY 



UNCULTIVATED land is generally covered with vegetation 

 of some kind. The plants grow without assistance in any 

 form from man. In fact, one of the difficulties with 

 which farmers have to contend is to keep down this natural 

 vegetation which interferes with the growth of crops. The 

 amount of produce from a given area of land, under purely 

 natural conditions, is, however, relatively small, and one 

 of the principal objects of cultivation is to increase it. 

 Improvements have been effected by experiments on 

 the plants themselves, some of which have been greatly 

 modified and rendered more suitable for use as food and 

 other purposes for which they are grown. This, how- 

 ever, is chiefly the work of specialists. The part of the 

 ordinary farmer is generally confined to the reproduction 

 of established types and assisting the development of the 

 plants by improving the conditions under which they grow. 

 This is effected chiefly by draining, tilling and manuring 

 the land in order to remove injurious substances and pro- 

 vide a plentiful supply of air, water and plant foods, i.e., 

 substances which the plants contain and which are neces- 

 sary for their growth. 



Soil. The soil is the natural habitat of plants. In 

 S.M. B 



