FERTILIZERS 



is set free and made available. Light sandy soil 

 has little water-holding capacity and is greatly 

 improved by the use of natural manures; the 

 organic matter occupies the open spaces of sand, 

 making it more compact and more capable of 

 holding water and plant-food in soluble form. 

 Commercial fertilizers only supply plant-food, 

 and do not improve the physical conditions of 

 the soil. Their great advantage is that they are 

 soluble and can be absorbed by the plants at 

 once, while the nitrogen, potash and phosphoric 

 acid in manures are largely insoluble and can 

 not be used by plants until after decomposition 

 begins. 



Nitrogen is one of the most important con- 

 stituents of fertilizers and one of the most ex- 

 pensive. When plants have a light, sickly ap- 

 pearance and their leaves are not in a good 

 healthy condition, it is evident that there is a 

 lack of nitrogen in the soil. Nitrates and am- 

 monia are soluble and can be distributed through 

 the soil in soil-moisture, being readily absorbed 

 by the root-hair of plants. The supply of nitro- 

 gen is derived from dried blood, dried meat or 

 animal matter, animal waste, dried garbage of 

 cities; other animal products less useful are 

 leather, wool, hair, cottonseed-meal, linseed- 

 meal, waste from castor-oil beans after extrac- 

 tion of oils. Valuable sources of nitrogen are 



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