COMMERCIAL FERTILIZERS 533 



while they obtained appreciable benefit from its use on 

 poor soils. They argue that since very productive soils 

 have great oxidative power the use of manganese is un- 

 necessary, but since poor soils undergo insufficient oxida- 

 tion the stimulation that this process receives by the 

 application of manganese is productive of much good. 

 Accordingly manganese is most profitably used on poor 

 soils not deficient in lime. 



