220 THE FARMER OF TO-MORROW 



particular case, the nitrogen was added by the 

 azotobacter present in the soil, bacteria which 

 feed on the decaying carbohydrates to be 

 found in suitable form in many plants. This 

 discovery suggested a pretty experiment to the 

 investigators of Rothamsted. They used 

 starch and sugar (which contain none of the 

 so-called mineral plant foods) with wonderful 

 results. Starch and sugar are carbohydrates 

 and thus furnished the necessary food in con- 

 centrated form for the busy bacteria. 



The experiment all but failed, because of 

 a peculiar accident which illustrates the many 

 complex forces that must be taken into account 

 by the soil expert. The first dressing, consist- 

 ing of a ton of sugar to the acre, gave no 

 results whatever. In fact the crop of barley 

 which succeeded the application was a total 

 failure. It was suggested that possibly the 

 sugar "fertilizer" was applied at a time of year 

 when the tiny micro-organisms were inactive. 

 It had been applied in winter. A second 

 test, with the sugar applied in the warm 

 spring months just previous to seeding, 

 resulted in a greatly increased yield of 

 barley. 



It was further found that the decaying roots 



