36 QUIKCE CULTURE. 



CHAPTER V. 

 MANURES FOR THE QUINCE. 



WHATEVER can be used to increase the fertility of the 

 soil by supplying plant food is a manure. The chemical 

 analysis of any plant will show its constituents, and give 

 the relative proportion of each, and so serve as a guide 

 in supplying what that plant needs. About nine- tenths 

 are water and air ; the rest is made up of earths and 

 metals, as lime, clay, iron, magnesia, silex, potash, and 

 soda, with gases and combustibles, as oxygen, hydrogen, 

 nitrogen, chlorine, carbon, sulphur, and phosphorus. 

 In the process of growth the plant selects such of these 

 as its nature demands ; and when it dies and decays it 

 restores to the earth these elements of fertility. 



Artificial fertilizers are made by mechanically com- 

 bining in desired proportions the elements of plant food, 

 to supply any deficiency of the soil under cultivation. 

 The action of any manure depends on its soluble salts. 

 "The salts contain the sulphur, phosphorus, and carbon, 

 as sulphuric acid, phosphoric acid, and carbonic acid, 

 and the chlorine as muriatic acid." 



All animal and vegetable matters in the process of 

 decomposition form ammonia. It is estimated that the 

 annual rainfall on an acre brings to the soil enough 

 ammonia and nitric acid from the air to equal one hun- 

 dred pounds of guano. The soil, to get the full benefit 

 of this atmospheric manure, must be kept porous to 

 receive it, and well drained that it may not run off on its 

 surface. When fire consumes vegetation, its gases return 

 to the air, leaving as ashes the earthy matters drawn from 

 the soil. In the process of decomposition the result is 

 the same, only the combustion is slower. 



Wood ashes contain all the elements of plant food ex- 

 cept nitrogen. Two and a half tons of seasoned hard 



