250 GARDEN GUIDE 



Green Manures 



Green manures aire so named because they are plants of various 

 kinds that are grown upon the soil, preferably when no other crop 

 could occupy it, and are spaded or plowed under in a green condition. 



Any kind of plant will make green manure, but the preference is 

 always given to those of the legume family. The blossoms of plants of 

 this family are, almost all of them, pea-like in character. All of the 

 Peas, Beans, and Glovers are legumes. Remarkable characteristics of 

 these plants are the knots or tubercles on the roots. Bacteria live in 

 these tubercles and store up in them the nitrogen existing in the form of 

 gas in the air. None of the other plants but those of the legume 

 family take nitrogen from the air and store it in the soil. If any 

 other green plants, such as Rye, Rape, Kale or Turnips are used for 

 green manure they simply return back to the soil what they have taken 

 from it. Even then they are of great benefit as they help, like manure 

 does, to bind the particles of sandy soils together and make clay soils 

 friable. They also furnish organic matter which, in turn, makes humus 

 that is of great value in holding the moisture in the soil. 



Commercial Fertilizers 



Commercial fertiUzers are so called because they are bought and 

 sold and gathered together from all parts of the earth. The dung of 

 sea bu-ds that had collected on some of the rocky coasts and islands of 

 South America was one of the earliest forms of commercial fertilizers. 

 It is called guano. Another was the bones of animals that were collected 

 in the desert places of the world and brought home and ground into 

 fine dust. Three of the important sources of the present day, are the 

 phosphate rocks of Tennessee, Florida, and South Carolina; the nitrate 

 beds of Chili, and the potash mines of Germany. The slaughter houses 

 and the garbage collected in the large cities also acjd their quota to the 

 commercial fertihzer groups. Other materials, such as the meal from 

 Cotton seed, after the oil has been pressed out ; the bones and other por- 

 tions of fish after the oil has been removed; the sulphate of ammonia 

 that is a by-product in the manufacture of coke, all help to increase 

 the fertilizer supply. There is also being manufactured at the present 

 time calcium nitrate, which is nitrogen that is taken from the air (by 

 means of electricity) and combined with lime. 



These materials are all used and are apportioned and mixed sa as 

 to supply varying proportions of the main food requirements of plants. 



