258 THE FARMER OF TO-MORROW 



They admit that such coating might take 

 place to some extent, but they contend that 

 since silica itself is soluble it could only act 

 as retarding the solution. 



The Rothamsted workers accept as estab- 

 lished the theory of the Bureau of Soils that 

 the physical texture of soils is much more 

 important in determining the immediate 

 productivity than chemical analysis. Their 

 principal quarrel with the Bureau of Soils has 

 to do with the theories advanced by the 

 Americans as to the part the organic constit- 

 uents of the soil play in soil fertility. We 

 will examine their objections in connection 

 with a statement of what these theories con- 

 sist of in the next chapter. It is sufficient to 

 say here that, in the words of Doctor Russell, 

 "they do not accept the American hypothesis, 

 but must admit they have none to offer in its 

 place." 



The American opponents of the "American" 

 theory rest their case on their own interpre- 

 tation of the results obtained in experiments 

 dating, in some instances, over periods of 

 twenty-five years. 



This historical data is far too voluminous 

 for the farmer in the field to reduce to broad 



