536 



EXPERIMENT STATION RECORD, 



The cliemical comjid^iitif)!! and alyfiorptivc power of these soils were as follows: 

 (JJunniatl ramjxmljoii <aid (ihsorjilire ]>oicer of .sf ji Is. 



rt The accuracy of this determination is doubtful. 



The experiments were begun on 3Iay 15 and concluded on October 17. The whole 

 time of the experiments was divided into 2 periods, (1) from May 15 to August 16, 

 and (2) from August 17 to October 17. On August 16 the soils were removed from 

 cylinders and analyzed, being replaced by new samples. The latter were removed 

 October 17 and analyzed. The drainage water was removed after each rain wnich 

 resulted in percolation. 



The following table gives the results of the experiments in 1895: 



Formation and loss of nitrates in bare soils in 1895. 



Number of soil. 



Amount of 

 I water per- 

 '• colated 

 from Mav 

 15 to Octo- 

 ber 17. 



1 



4 



5 



6 



7 



9 



Mean 



Cc. 

 594.0 

 64.5.0 

 622.0 

 672.0 

 702.0 

 753.0 



N0O5 in a 

 liter of 



drainage 

 water. 



NoO-. formed inl kilogram of soil- 



664.6 



Mg. 

 232.4 

 86.3 

 42.6 

 78.0 

 103.1 

 69.2 



From 



Mav 15 to 



Aug. 16. 



Mg. 

 51.21 

 30.39 

 16.31 

 .5.02 

 3.5.77 

 19. 93 



101.5 



26.45 



From 



Aug. 17 to 



Oct. 17. 



Mg. 

 11.05 

 4.17 

 7.03 

 23. 67 

 24. 99 

 10.45 



13.56 



Mg. 



62. 26 

 34.56 

 23. 34 

 28. 69 

 60.76 

 30. 38 



39.99 



Ratio of 

 the water 

 percolated 

 to that of 

 the rain- 

 fall. 



1:4.4 

 1:4.1 



1:4.2 

 1:3.9 

 1:3.7 

 1:3.4 



1:4.1 



The above data show that with reference to the energy of nitrification the soils 

 arrange themselves in the order indicated by the chemical and mechanical analysis as 

 indicated above. Soil No. 1, rich in nutritive substances and mellow, gives the largest 

 amount of nitrates, while soil No.- 5, the poor podzol, difficultly pervious to water 

 and air, gives the least umount. Soils Nos. 6 and 7 appear to be exceptions. In the 

 opinion of the author, an error was made in the experiments with soils Nos. 6 and 7. 

 Nitrification was more energetic in the first period than in the second, obviously on 

 account of higher general temperature. On an average approximately one-fourth of 

 the rainfall percolated through a layer of soil 20 cm. in thickness. 



In 1896 similar experiments were made with 3 of the above-described soils, Nos. 

 1, 4, and 7. With the last soil 2 experiments were made. One was carried out in 

 the usual way, while in the other the soil was taken from the cylinder in layers, pul- 

 verized, mixed, and returned to the cylinder, introducing the layers in the same 

 order as in the normal soil. The object of the last experiment was to study the 

 influence of stirring the soil upon the energy of nitrification. 



The results show that ( 1 ) the energy of nitrification in 1896 was much greater than 

 in 1895, which was undoubtedly due to a higher temperature prevailing in 1896; (2) 

 as m 1895, the better soils formed larger (quantities of nitrates; and (3) soil No. 7, 

 mixed, gave more nitrates than the same soil in normal condition, the increase being 

 9 8 per cent. On the other hand, the difference in the amount of nitrates washed 



