480 EXPERIMENT STATION RECORD. 



Humus, which is iusoluble iu water, was fouud to be soluble in the 

 infusion on account of the amiuouia formed, but the humus was again 

 rendered insoluble by adding to the infusion a little soil containing 

 nitrifying ferments. 



Less ammonia and more nitrate was found in the soil with which 

 vegetable remains were intimately mixed than in the one on which 

 this matter was simply spread on the surface. The stirring attend- 

 ing the incorporation of such matter in the soil, of course, accelerated 

 nitrification. 



When the production of ammonia has proceeded to the point of 

 destroying the organisms producing it, fungi aj)pear which convert 

 the ammonia into organic compounds again. In meadows, peat bogs, 

 etc., in which vegetable matter accumulates the nitrifying ferment does 

 not exist, but fungi feed on the ammonia formed and thus enable the 

 organisms producing the ammonia to continue their activity. What is 

 meat for the former is poison for the latter. 



On the cultivation of the soil, P. P. Deherain {Ann. Agron., 22 

 (1896), No. 10, pp. 449-469). — This is the first paper of a proposed series 

 and is devoted to the aeration of the soil. 



Samples of soil were taken by driving down into the soil in situ boxes 

 7.87 in. square and 5.91 and 7.87 in. deep, and removing the prisms of soil 

 thus inclosed. These were weighed, dried, and weighed again. If A = 

 the actual volume of the soil, B the volume of the water it contains, D 

 the density of the dry soil, and X the air which the soil contains, then 



A 



V (original volume of the soil) = yy + B + X, from which X is easily cal- 

 culated. This method was applied to numerous samples representing 

 meadow and forest soils, spaded soil, and soil plowed in autumn and 

 afterwards cultivated in the spring (harrowed and rolled). The results 

 show that the above method gives approximately accurate results, 

 check determinations agreeing closely. It appears that uncultivated 

 soil contains considerable amounts of air. This is true of meadow and 

 forest soil as well as that covered with spontaneous vegetation. While 

 much more air was found in cultivated than in uncultivated soils, this 

 difference was hardly sufficient to explain the utility of cultivation. A 

 light soil left to itself undergoes internal rearrangement of particles 

 which increases the total space. Kolling reduces this space and 

 decreases aeration. Harrowing to break clods is very important 

 because clods exposed to the air lose all of their oxygen, and conse- 

 quently the oxidation of the organic matter is interfered with. Unsea- 

 sonable cultivation which produces clods therefore seriously interferes 

 with the aeration of the soil. 



The influence of irrigation on meadows, J. Konig {Landtv. Vers. 

 Stat. Miiuste)-, JEine DenTcsclirift, 1896, pp. 142-152).— This is a summary 

 of work in this line at the Miinster station during the last 20 years, upon 



