THE SOIL 109 



supplies of vegetable matter from time to time, so that it 

 may decay and become mingled with the soil as humus. 

 Good agriculturists take care to save and dig into their 

 fields and gardens all the available refuse vegetable 

 matter, such as manure and stable refuse, dead leaves, 

 twigs and grass. We shall have to refer to these later 

 when dealing with the question of manures. 



The very wasteful habit is often adopted of burning 

 a great deal of refuse vegetable matter instead of burying 

 it in the soil to form humus. It is not uncommon to 

 find a man busily engaged in burning leaves, and other 

 vegetable refuse, and at the same time lamenting that 

 this soil is becoming worn out. Instead of being burnt 

 these things should be dug into the soil, or, if that is in- 

 convenient or impracticable, they should be thrown into 

 heaps and allowed to decay partially. Loss of valuable 

 plant food may be prevented by covering the heap with 

 layers of soil, which also prevents the production of any 

 offensive smell or other unpleasantness. Such heaps 

 are known as compost-lieaps^ and if adopted in every 

 garden the laments about worn-out soil would cease. 

 It is often urged that by burning the leaves, twigs, etc., 

 plant ashes are obtained which are of value when added 

 to the soil. This is true. The important fact, however, 

 is usually overlooked that the leaves before burning are 

 made up, speaking generally, of ash and organic matter, 

 and that when burnt the most valuable portion, the 

 organic matter, burns away and is lost. The ash is thus 

 added in either case, but by not burning the matter, we 

 add the most valuable portion, the organic matter, in 

 addition. 



