168 THE SPIRIT OF THE SOIL 



There are few who have as much as they could use 

 to advantage, with the result that they have either 

 to apply it sparingly or rely entirely on artificials for 

 a portion of the green crop and grass areas. Its 

 action being quicker than that of dung, it might be 

 thought that its stimulating energy was largely 

 expended in the first year. Recent tests made in 

 the laboratory, however, show that the treated 

 Kew soil after a season's growth still contains a large 

 amount of available food material, and that the 

 nitrogen-fixing bacteria are still active and capable 

 of producing further nitrogenous plant food. Ex- 

 perience alone can decide this and other important 

 points, but in the meantime it is satisfactory to have 

 evidence that an important addition is likely to be 

 made to our resources. It is interesting to know 

 that there is virtually no limit to the production of 

 the material. If there is any limitation it is in the 

 quantity of the moss available, since the bacterial 

 cultures are capable of indefinite multiplication." 



