COMMERCIAL FERTILIZERS CONCLUDED 2 I ^ 



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THE SOIL 



Soils that are poor in humus are generally in need 

 of nitrogen. 



Heavy soils are generally supplied with potash 

 but lack phosphoric acid. 



Sandy soils are apt to be poor in potash and 

 nitrogen. 



SYSTEM OF FARMING 



A system of general or diversified farming cm- 

 bracing crop products and stock raising, requires 

 much less artificial manuring than does a system 

 which raises special crops or quick growing crops 

 in rapid succession, as in the case of truck farming 

 or market gardening. 



TESTING THE SOIL 



Every farmer should be more or less of an inves- 

 tigator and experimenter. 



The factors mentioned previously as indicating 

 the presence or absence of sufficient quantities of 

 certain plant foods serve as a general guide, but 

 are not absolute. The best method of determining 

 what plant foods are lacking in the soil is to carry 

 on some simple experiments. 



The following plan for soil testing with plant 

 foods is suggestive : To test the soil for a possible 

 need of the single plant foods, a series of five plots 

 may be laid off. These plots should be long and 



