718 EXPERIMENT STATION RECORD. [Vol. 3T 



of solution may be obtained without its coming in conUict with the oiL If it 

 does it can be easily separated by cooling and by the separatory funnel. 



" The concentration of the soil solution from different samples of the same type 

 of soil varies according to the moisture content of the samples from which it 

 is derived. Successive portions of tbe same extraction vary only sligiitly in 

 their physical properties, but to a considerable extent in the varioius forms of 

 nitrogen. The forms of nitrogen vary in the different solutions. , . . Calcium 

 and magnesium also vary according to the treatment and reaction of the soil. 

 The phosphoric acid la fairly constant Potash varies somewhat A small 

 percentage of the bacteria are removed from the soil, since the soil acts as a 

 filter. Anaerobic changes take place in the cylinder if it is allowed to stand 

 for a long time. 



" The paraffin oil displacement-pressure method furnishes ... a fair repre- 

 sentiitive of the solution as it exists in the soil. The method permits the use 

 of a large amount of soil, thus a better representative snmple. Work now in 

 progress indicates that It furnishes a valuable index of the microbial changes 

 In the soil." 



Ie the humus content of the soil a gruide to fertility? R. H. Carr {Soii 

 Set., 5 (1911), No. 6, pp. 515^2^. figs. 5). — Experiments conducted at Purdue 

 l^nivergity using a surface clay soil very deficient in organic matter and differ- 

 ent organic manures are reported. 



" The results of the vegetation and huraification tests seem to show that 

 whenever there is rapid humiflcation of manure the growth of the plant is 

 greatly stimulated, indicating that 'the decay of organic matter is desirable in 

 plant growth and not Just its mere presence,' This was especially noticeable 

 when green manures were rolled \mder and limed as compared with disking or 

 mixing the manures uniformly with the soli. 



" Certain of the manures seem to be as soluble In a 4 per cent ammonia when 

 just mixed with the soil as after humiflcation. ThLs was found to be true with 

 alfalfa and steer and somewhat with cow manures. Horse manure seemed to 

 humify slowly and its plant food was largely unavailable to corn during the 

 first year, but the humiflcation and vegetation tests show it becomes more avail- 

 able in the second year. It was possible to Increase the rate of huraification 

 of horse manure in the first year by adding dolomitlc limestone, which resulted 

 in a greater yield of corn than where humiflcation had not taken place. 



" The organic residues left in the soil from manure treatment were not ver>' 

 effective during the second year in producing a growth of com, probably be- 

 cause the most avuil.'ible or valuable complexes had disappejired In the first 

 year. There is no apparent relationship between the percentage of ash in 

 humus and the growth of com. The humificntlon and vegetation tests seem to 

 Indicate a rather close relationship between the amount of humus and the 

 growth of corn." 



Effect of the addition of orgunic matter to the soil upon the development 

 of soil acidity, M. P. Miixer {Missouri Sta. BuL llfl (1911), pp. 50, 5/).— The 

 results reported in general indicate "that the ordinary green manures turned 

 under cither dry or fresh do not increase soil acidity, although ;i crop containing 

 much sugar, as in the case of sorghum, does appreciably Increase soil acidity for 

 a few weeks. This acidity later decreases." 



Is there any fungrus flora of the soilP S. A. Waksman (Soil Sci., S (1911), 

 No. 6, pp. 565-5S9). — Studies at the New Jersey Experiment Stations of the 

 fungus content of 25 soils collected under sterile conditions from different parts 

 of North .\nierica and the Hawaiian Islands are reported. 



Over 200 species of fungi were isolated. It was found that the more fertile 

 soils contained more fungi, both In number and species, than the less fertile 



