50 CHEMISTRY, GEOLOGY 



but little value, by their careless mode of prepar- 

 ing or keeping it. 



ON THE APPLICATION OF MANURES TO THE 

 SOIL. 



Everything that supplies food to plants through 

 the soil may be called a manure. There are 

 three distinctive kinds of manures : vegetable, 

 animal, and mineral. Vegetable manures are 

 those parts of plants that are buried in the soil, 

 which they enrich by the process of decomposi- 

 tion or rotting, whereby the substances of which 

 they are composed are returned to the land. 

 Grass, clover, straw, hay, potato-tops, corn- 

 stalks, etc., are amongst the most valuable 

 NO. 16. of the vegetable ma- 



nures. Sometimes a 

 crop of green grass is 

 used as a manure, by 

 being ploughed into 

 the soil. When grass 

 is to be ploughed up for manure, the sods should 

 not be deeply buried ; they should be left so near 



Questions. What is a manure ? How many kinds of 

 manure are there ? Of what do vegetable manures consist ? 

 Should green crops be deeply ploughed in for manures? 



