Relations of Higher Plants to the Formation of Nitrates 37 



the fact that the absorption of nitrogen by the millet crop had practically 

 ceased at that time. The millet sowings of July 24 and August 6 show 

 the same phenomenon. 



Soy beans do not exhibit this property to the same degree. Between 

 the dates mentioned there was a slight increase in nitrates under the 

 sowing of July 5, and a marked increase under the sowing of July 24. 



Experiments with maize, millet, and weeds in 1908 

 The plan of experiments in 1908 was primarily the same as that in 1907; 

 soy beans were not used, however, and there was a difference in the 

 arrangement of the planted and the unplanted sections of the plats and 

 in the character of the soil, all of which have before been noted. Analyses 

 were made only on July 22 and August 31. In Table 11 is given a com- 

 parison of the amount of nitrates in the planted and the unplanted sections 

 of the check plats, all of which received the same treatment: 



TABLE 11. Nitrates in Maizk and in Unplanted Sections 

 22, 25, IN 1908 (Parts per Million) 



ON Plats 1. 



4, 7, 10, 19, 



Plat 



July 22 



August 31 





Maize 



Unplanted 



Maize 



Unplanted 



1 



85 



66 



78 



75 



172 



140 



140 



66 



60 



64 



69 



102 



143 



101 



99 

 90 



107 

 105 

 112 

 99 

 126 



79 



4 



7 ■ 



10 



19 



22 



25 



82 

 79 

 48 

 82 

 75 

 75 



Average 



108 



86 



105 



74 







The higher nitrate content of the planted soil on July 22 is in line 

 with previous results; a similar relation on August 31 is not, however, 

 as the nitrate content mider maize is usually low at that time. The 

 growth of maize was very poor on these plats, the plants growing only 

 three or four feet high and producing only about one third of a crop of 

 fodder. There was consequently a very small absorption of nitrogen 

 as compared with a normal crop. 



