WORK OF BACTERIA 



were unable to use free atmospheric nitrogen and 

 must obtain it directly from the soil in a highly or- 

 ganized form, the importance of the problem increased 

 greatly, and the gravest consequences were predicted 

 by those familiar with the rapidity with which this 

 valuable element was being wasted." Farmers' Bulle- 

 tin No.' 214, Beneficial Bacteria for Leguminous 

 Crops. 



Nitrogen in combination available for plant food is 

 wasted in many ways. Food and other organic wastes, 

 as sewage, are burned or run into the sea instead of 

 being returned to the earth, which is the natural place 

 of disposal. 



There are natural sources of stored nitrogen in 

 saltpeter beds and guano deposits, but these are rapidly 

 disappearing. Even if they were sufficient in quantity 

 they are not everywhere present and therefore must 

 be expensive. Their aid would not be available for all. 



The bacteria are more generally present and ready 

 to work. Although unknown and therefore uncred- 

 ited, they have been working during all the ages since 

 vegetation appeared, not only by their general agency 

 in producing fertility of the soil through the products 

 of decomposition, but also in certain plants through 

 their ability to take from the air its free nitrogen. 



From the earliest days of agriculture it has been 

 recognized that all plants belonging to the leguminosae 

 have a decidedly beneficial effect upon the soil. Pliny 

 wrote: "The bean ranks first among the legumes. 



Waste of 

 ftitrogen 



