14 THE FOOD OF PLANTSMANURING [CH. 



able soil into cultivation. In this way, as is shown in 

 the diagram, the food-store is again doubled, the root area 

 further extended, and just in proportion as the roots 

 extend below can the stems and branches flourish above. 

 With a free and healthy root-action in such deep fertile 

 soil, the growth of the plant becomes more active and 

 the produce much better, at least so far as the tiller of 

 the land can secure it ; for of course at best he can only 

 improve, he cannot change, the nature of the soil. 



It should be borne in mind, however, that inexperienced 

 workers may do more harm than good by vicious methods 

 of trenching,* and there is perhaps no process in horti- 

 culture which so much needs the help of an expert as 

 the art of using the spade judiciously. In this depart- 

 ment half an hour's practice on the ground is worth 

 more than a whole chapter's instruction on paper. 



CHAPTER III 

 THE FOOD OF PLANTS MANURING 



WE have endeavoured to explain the nature and the 

 use of the soil as the anchorage and storehouse of our 

 plants. It remains to add a word or two as to the 



* For instance, when the subsoil is of a clayey nature, great harm 

 would be done by bringing up such raw material to the surface at 

 once, but great benefit would accrue by incorporating with the bottom 

 spit, manure, or even sand or road-grit. 



