PERMANENT AGRICULTURE 



337 



manure heap or even by the odor of ammonia about the 

 barnyard. It is due to bacteria which can exist only in 

 the presence of air ; and if the manure heap is kept com- 

 pact and moist, it maj' be easily prevented. 



Not^\'ithstanding the necessity of supplementing barn- 

 yard manure with legumes or with other fertilizers, it is 

 still true that it is by far the most valuable fertilizing' 

 agent known. The farm, on which all crops produced 

 are fed to live stock and the manure carefully preserved 

 and returned to the land, will continue profitable produc- 

 tion from three times to five times as long as will one 

 from which all crops are sold. It is for this reason that 

 " stock " farms are almost invariably found to be more 

 productive than adjoining " grain " farms. It follows 

 of course that there should be enough live stock on every 

 farm to consume all, or practically all, the grain and forage 

 which it produces. 



