CHAPTER II 

 FERTILIZERS 



8. Kinds. There are thi-ee general sources of fertilizer, 

 or plant food; stable manures, chemical fertilizers and green 

 manures. The term " green manure " is used to designate 

 such crops as cow peas, crimson clover, rye and other green 

 crops grown for ploughing under. Such crops add humus to 

 the soil and, when a leguminous crop is ploughed under, 

 a considerable amount of nitrogen is also added to the 

 soil. Green crops are usually ploughed under in the spring 

 although it is often desirable to plough the croD under in the 

 fall. 



9. Stable Manures. Stable manures are more gen- 

 erally used than any other source of plant food for grow- 

 ing vegetables. In many instances, they are the cheapest 

 source of plant food obtainable, as when the grower is located 

 near a large city and the stable manure may be had at small 

 cost or for hauling it away. In other ihstances, manure 

 brings a good price and is often shipped long distances for 

 the market gardener. Rotted stable manure is the Ijest 

 fertihzer for the garden, for not only is a supply of quickly 

 available plant food added, but stable manure also furnishes 

 a store of humus in its most desirable condition for readily 

 incorporating with the soil. Stable manure runs compara- 

 tively low in its plant food value. It is estimated that a ton 

 of partly rotted stable manure is worth about $2.00 for 

 the plant food contained in it; it is of course worth more 

 than this to the gardener because of its supply of humus. 



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