154 Commercial Gardening 



with wool waste and shoddy as manures. They all contain appreciable 

 quantities of nitrogen, and when thoroughly decomposed and matured by 

 mixing with layers of soil, they constitute valuable organic additions to 

 the soil. 



4. NITROGENOUS MANURES 



Nitrogenous manures are chiefly valuable because they give a luxuri- 

 ance and brilliancy of colour to the foliage of plants, thus enabling them 

 under healthy conditions to absorb sufficient supplies of carbonic acid gas 

 from the atmosphere during the daytime. The practical gardener may 

 therefore by a mere glance at his plants be able to say whether his plants 

 are lacking in nitrogenous food or not. When the leaves are luscious and 

 deep green, and the shoots are gross and sappy, it is a sure sign that there 

 is an abundance of nitrates in the soil. Such rank growth can only be 

 produced by their presence. It would therefore be a mistake to add nitro- 

 genous manures to such a soil. To check the rankness of growth, however, 

 it would be wise to add phosphates, potash, or lime, and thus induce the 

 formation of flowers and fruits instead of wood. 



Amongst natural substances which supply nitrates to the soil are farm- 

 yard and stable manure, leaves, the dung of such animals as the horse, cow, 

 pig, sheep, poultry, rabbit, and all refuse from them, such as wool, shoddy, 

 horn, hair, feathers, skin, leather, meat meal, dried blood. To these may be 

 added fish manure, oilcake manure, night soil, and poudrette. 



Indeed these materials not only supply nitrogen, but also certain quan- 

 tities of potash, phosphoric acid, and lime, as well as other foods. They 

 may therefore be looked upon as complete fertilizers. 



Amongst artificial manures supplying nitrogen are nitrate of soda, 

 sulphate of ammonia, nitrate of potash, nitrate of lime, nitrogen, and 

 guano. 



When the natural manures, which are all of animal origin, are incor- 

 porated with the soil, and are in a thoroughly decayed condition, they 

 possess all the advantages of humus, and are safe and reliable. They keep 

 the temperature equable, retain sufficient moisture, bring bacteria into 

 being, dissolve mineral matters, and gradually yield up their foods to 

 the roots of the plants. 



Nitrate Of Lime. This is a new nitrogenous fertilizer produced from 

 the oxygen and nitrogen of the atmosphere by an electrical process. The 

 commercial product is a hard crystalline substance which contains about 

 13 per cent of nitrogen. It is very soluble in water and has the disad- 

 vantage of being very deliquescent, owing to its affinity for moisture in the 

 air. It must therefore be kept in a very dry place, and it is best used as 

 a topdressing to growing crops in the same way as nitrate of soda. 



Nitrate of Soda OP Chili Saltpetre. This is one of the best-known 

 artificials, and enormous quantities are sold every year. It is found in 

 layers of varying thickness in parts of Chili, whence 1,738,540 tons wen; 



