CHAPTER XIX 

 FARM MANURES 



FUNCTIONS OF MANURES AND FERTILIZERS 



IN Chapter II we learned that the roots of plants 

 for their growth and development need a soil that 

 is firm yet mellow, moist, warm, ventilated and sup- 

 plied with plant food. We also learned that of the 

 plant foods there is often not enough available nitro- 

 gen, phosphoric acid, potash and lime for the needs 

 of the growing plants. 



Manures and fertilizers are applied to the soil for 

 their beneficial effects on these necessary conditions 

 for root growth and therefore to assist in -main- 

 taining soil fertility. 



CLASSIFICATION OF MANURES AND FERTILIZERS 



Manures may be classified as follows : 



f Barn or stable manures, 

 Farm manures, j Green-crop manures, 

 I Composts. 



f Materials furnishing nitrogen, 



Commercial fer- I (l (t phos phoric acid, 



tilizers or arti- i potash> 



ficial manures. [ tt l( 



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