14 T. Lyttleton Lyon and James A. Bizzell 



more active nitrate formation in the soil growing oats or to the utilization 

 of some form of nitrogen other than nitrates. The investigators did not 

 think that a decomposition of nitrates could account for it. 



Similar results with clover were obtained by the same investigators, but 

 since clover is a legume this may be accounted for by processes already 

 understood. 



Results reported by Jensen (1910) showed that soil planted to maize 

 contained more nitrates during the first part of July than did fallow land. 



Fraps (1908) found that fifty to one hundred per cent more nitrogen was 

 removed by maize plants in the first nine weeks of their gro'^i;h than was 

 apparently transformed from organic compounds into ammonium and 

 nitrate salts in the same time. 



Bower (1912) determined nitrates in soil of unplanted plats, both culti- 

 vated and uncultivated, and in maize plats cultivated and uncultivated. 

 In both the cultivated and the uncultivated plats nitrates under the maize 

 were higher during Jul}' than in the bare soil. 



In the experiments cited showing a higher nitrate content of soil under 

 maize than in fallow land, this condition obtained during the period of 

 active groA\i:h and usuall}' before full bloom. The experiments in which 

 an miaccountable nitrogen supply was indicated also relate to the earlier 

 stages of gro^^i;h. They agree in suggesting an activitj^ in nitrate forma- 

 tion under certain plants during earl}" growth which does not obtain in 

 unplanted soil. 



Experiments indicating a dejjressed nitrate Jormation under plants 

 Brown and Maclntire (1910) found that the nitrates in oat land did 

 not increase after the crop began to mature until after plowing in the fall. 

 The plowing was done on August 20. 



Leather (1912) reports experiments in which large tanks containing soil 

 were planted or fallowed and nitrate nitrogen was determined in the 

 drainage water. Of these gauges, numbers 1 and 3 were cropped and 

 numbers 2 and 4 were fallowed. In 1909 the rainfall was sufficient to 

 replace entirely the water m the gauges. The nitrogen in the crops of 

 1908 and 1909 plus the nitrogen in the drainage water for that period 

 should be, Leather thinks, equal to the nitrogen in the drainage water of 

 the fallow gauges. He shows by the following figures, however, that this 

 is not the case: 



