496 



EXPERIMENT STATION RECORD, 



Nitrification in different soils collected in the spring. 



Soil. 



Grignon } 



Marmilhat (Puy de Dome) 5 



Palbost (Puy de D6me) i 



Seine-et-Marne < 



Blaringhem (N"ord) < 



"Wardrecqiies (Pas-de-Calais) i 



Temperature. 



30OC 



Ordinary . . 



30°C , 



Ordinary . , 



30OC 



Ordinary . , 



30° C 



Ordinary . 



30° C 



Ordinary . 



30° C 



Ordinary.. 



Nitric nitrogen found 

 in 100 gm. of soil. 



7.8 

 5.4 

 14.0 

 10.9 

 6.9 

 4.0 

 4.7 

 3.1 

 5.5 

 4.7 

 6.7 

 4.0 



Mq. 



7.8 



fi. 6 



17.5 



13.7 



23.7 



7.5 



7.1 



4.4 



6.3 



5.3 



7.5 



4.9 



Mg. 



9.7 



7.6 



20.0 



15.7 



24.0 



10.0 



8.7 



7.0 



8.0 



7.3 



8.4 



6.6 



Nitric nitrogen per hec- 

 tare of 1,000 tons. 



Kg. 



78 

 54 

 140 

 109 

 69 

 40 

 47 

 31 

 55 

 47 

 67 

 40 



Kg. 



78 

 66 

 175 

 137 

 237 

 75 

 71 

 44 

 63 

 53 

 75 

 49 



Kg. 

 97 

 76 

 200 

 157 

 240 

 100 

 87 

 70 

 80 

 73 

 84 

 66 



In certain of the soils nitrification went on actively from the begin- 

 ning. On March 27 Marmilhat soil gave 10.9 mg. at the ordinary 

 temperature and 14 mg. at a temperature of 30° 0., while samples 

 collected in the month of January gave only 6,6 mg. after a month had 

 elapsed. In the Marmilhat soil the nitrates increased during the fol- 

 lowing month, but less rapidly than in the case of the Palbost soil, 

 which furnished moderate quantities on March 27, but increased the 

 amount very rapidly, until on April 10 it furnished 23.7 mg. and on 

 April 24, 24 mg,, the highest figures in the series. 



The soils collected in the month of March nitrified, therefore, much 

 more actively than those collected in January, but they furnished less 

 nitrates than those collected in autumn. The sample of Palbost soil, 

 which gave, after pulverization in October, in one case 57 mg. of nitric 

 nitrogen and in another 71 *mg., furnished in the above experiments a 

 maximum of only 24 mg., although it was kept under conditions of tem- 

 perature, etc., much more favorable than those which surrounded the 

 samples spread out in the station building the preceding autumn. 



It must not be assumed, however, that soils collected in the spring 

 are always in a condition less favorable to nitrification than those col- 

 lected in other seasons, since a soil from Seine-et-lNIarne collected at 

 the end of winter furnished in the drainage water of March and the 

 beginning of April 66 kg. of nitric nitrogen per hectare of 1,000 tons in 

 one case and 80 kg. in another, although tliese figures were calcu- 

 lated on the nitrogen content of the drainage water, which of course 

 less coini)letely removes the nitrates from the soil than the leaching to 

 which small samples of soils are subjected in the laboratory. 



Nevertheless it is true iu general that the drainage water of spring 

 removes less nitric nitrogen from the soil than that of summer and 

 autumn. This will be clearly seen on examination of the results obtained 

 by analysis of the drainage water of unfertilized and unj)ulverized Grig- 

 non soils shown in the following table: 



