334 EXPERIMENT STATION RECORD. 



" (5) Rolled ground, when dry, showed an increase in soil moisture for the first few 

 days. It also showed a larger decrease in the second foot during 32 days. 



"(6) Other things equal, the rapidity of the growth of plants depends upon the 

 moisture content of the soil. . . . Alkali soils do not contain as much moisture as 

 ordinary prairie." 



On the fixation and nitrification of nitrogen in arable soils, 

 P. P. Deherain (Gompt. Rend. Acad. Sci. Paris, 125 (1897), No. 5, pp. 

 278-283). — Determinations of nitric and organic nitrogen were made at 

 frequeut intervals from December, 1895, to March, 1897, in a cubic 

 meter lot of soil which was spread out in a stable and kept in the 

 state of moisture most favorable to nitrification — 20 to 25 per cent. 

 During that i>eriod the nitric nitrogen increased from 0.14 to 1.66 gm. 

 per kg., and the organic nitrogen declined from 3.13 to 2.57 gm., the 

 increase in total nitrogen being from 3.27 to 4.23 gm. In case of another 

 soil treated in the same way the nitric nitrogen increased from 0.23 

 to 2.32 gm. 



These results show that the decrease in organic nitrogen was not 

 sufficient to account for the increase in nitric nitrogen, and indicate 

 that a considerable amount of the free nitrogen of the air was fixed by 

 the soil during this period. That the increase of total nitrogen in the 

 soil was not due to the absorption of ammonia fumes was demonstrated 

 by a check experiment carried out in the basement of the station build- 

 ing, which was kept free from ammonia fumes. Here also there was 

 a considerable increase in nitrogen. 



An insufficient supply of moisture checked the fixation and nitrifica- 

 tion of nitrogen almost completely. This occurred in one of the soils 

 when the moisture content had only been reduced to 16.5 per cent. 



Denitrification, G. Ampola and E. Garino (Gentbl. BaJct. u. Par., 2. 

 AM., 1897, p. 309; abs. in Chem. Ztg.,21 {1897), No. 71, Repert..p. 190).— 

 The loss of nitrogen from barnyard manure is claimed to be due to the 

 action of denitrifying organisms. Acids prevent this action. The addi- 

 tion of ground peat showing an acidity of 9.85 per cent checked the 

 activity of the denitrifying organisms as well as that of the other 

 ferments. The organisms, however, were not killed and commenced 

 their activity again as soon as the acidity was neutralized. The soil 

 conditions are favorable to the neutralization of the acid of the peat, 

 and thus the restraining effect of the latter on the denitrifying organ- 

 ism is nullified in the soil. 



On the role which humus substances play in the fertility of the 

 soil, A. Gautier (Gompt. Rend. Acad. Sci. Paris, 124 (1897), No. 22, pp. 

 1205-1206). — The author claims that free nitrogen is fixed in apprecia- 

 ble amounts by algse and microorganisms in the soil only in the pres- 

 ence of humus compounds, and that the nitrogen so fixed is directly 

 assimilable by the higher plants. If the soil is deficient in humus the 

 various organisms which fix nitrogen do not develop to a sufficient 

 extent to enrich the soil in nitrogen. 



On the determination of the potash in soils soluble in citric 

 acid, O. VON Garola (Rev. Ghim. Analyt. et Appl., 5 (1897), p. 101; abs. 



