HOW TO MAINTAIN FERTILITY 



which to supply humus, because the soil is receiv- 

 ing at the same time nitrogen, phosphoric acid, and 

 potash, the three most important elements in plant 

 foods. It is vegetable matter that has been partly 

 digested by animals and is in a condition to be 

 more quickly assimilated by plants than is a green 

 manure. 



Green manure is supplied by growing a crop of 

 clover, or other leguminous plants, or rye, and 

 turning it under. I have seen comparatively un- 

 productive sandy soils from which nitrogen was 

 leached out by rains as fast as it could be supplied, 

 brought into good tilth and produce large crops 

 by its use. In the small garden, where one cannot 

 afford to lose the time necessary to do this, as it 

 is done in large farming operations, rye or clover 

 can be sown in the fall as soon as the vegetable 

 crops have been removed, or between the rows at 

 the last cultivation of such crops as corn, and what- 

 ever growth has been turned under at the time of 

 spring ploughing. I have seen this done with good 

 results on small areas. 



The clovers and other leguminous crops are the 

 best green manures because of their ability to 



absorb and fix free atmospheric nitrogen. If you 



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