CONTENTS PAGE 



Introduction 9 



Experiments by other investigators . . 11 



Experiments showing different nitrate contents of soils under 



different crops 12 



Experiments showing, higher nitrate content under plants than in 



fallow land 13 



Experiments indicating a depressed nitrate formation under 



plants 14 



Investigations at the Cornell University Agricultural Experiment 



Station 16 



Experiments on plats manured for timothy 16 



Seasonal range of nitrates under timothy, maize and oats . . 19 



Nitrates on the planted and the unplanted sections of the plats 20 



Relation of nitrates to soil moisture on the plats 25 



Changes in soil moisture 26 



Some relations between soil temperature and nitrate forma- 

 tion 31 



Experiments with maize in which other plants were sown 32 



Experiments with maize, millet, and soy beans in 1907 34 



Experiments with maize, millet, and weeds in 1908 37 



The excessive supply of nitrates in soil planted to maize 39 



Nitrates in soil planted to maize, potatoes, and oats 41 



Experiments in 1910 41 



Nitrates at different depths 43 



Experiments in 191 1 45 



Experiments in 1912 64 



The relation of the nitrate content of the soil to the quantities of 



nutrients removed by crops 73 



The influence of alfalfa and of timothy on the production of 



nitrates in soil 74" 



The nitrate-producing power of alfalfa soil and of timothy 



soil 75 



The nitrate content of alfalfa soil and of timothy soil 80 



5 



