514 EXPERIMENT STATION BECOBD. [Vol.35 



germination and the smallest amotint the time preparatory to actual spore 

 formation. M. sitophila shows the largest ammonia accumulation within the first 

 3 or 4 days ; Penicillium sp., between 10 and 15 days ; and M. plumbeus, between 

 6 and 10 days. These periods correspond to those of active spore formation 

 for the respective organisms." 



Preliminary experiments on some effects of leaching on the soil flora, 

 C. B. LiPMAN and L. W. Fowlek {Soil ScL, 1 (1916), No. 3, pp. 29i-297 ) .—Pre- 

 liminary laboratory experiments conducted at the University of California on 

 the processes of ammonification, nitrification, nitrogen fixation, and cellulose 

 decomposition in clay loam and blow-sand soils when unleached and leached in 

 the presence or absence of 0.1 per cent sodium chlorid, 0.25 per cent sodium 

 sulphate, 0.05 per cent sodium carbonate, or a combination of 0.1 per cent 

 sodium chlorid, 0.05 per cent sodium carbonate, and 0.1 per cent sodium 

 sulphate, are reported. 



The results obtained are taken to indicate that "leaching affects the bacterial 

 flora of soils profoundly. . . . This is particularly so for the nitrifying, nitro- 

 gen-fixing, and cellulose-destroying organisms. All of these processes appear to 

 be wholly or almost wholly checked by leaching, especially if salts are present 

 prior to the execution of the latter process." 



A list of seven references to literature bearing on the subject is appended. 



Nitrification in relation to the reaction of the soil, J. W. White {Pennsyl- 

 vania Sta. Rpt. 1914, pp. 70-80, pis. 4)- — Studies of nitrification and the nitrate 

 content of acid soils and soils made acid, especially by treatment with ammo- 

 nium sulphate, are reported, the results of which are taken to indicate that 

 nitrification does not cease in very acid soils. Soil on which corn and wheat 

 failed was found to be liberally supplied with nitrates. 



"The absence of nitrates under growing plants is no indication of the in- 

 activity of nitrifying organisms. The variation in nitric nitrogen content of all 

 areas on ammonium sulphate plats is parallel to the unequal distribution of vege- 

 tation. An average plat showed 24.91 parts per million of nitric nitrogen in 

 corn stubble, 13.14 parts per million on clover sod, 9.23 parts per million under 

 clover and timothy, and 36.47 under winter wheat." 



Applications of burned lime and ground limestone to soil from the plat 

 materially stimulated the activity of nitrifying organisms. Magnesian lime 

 gave higher nitrates than pure lime. Failure of clover, corn, and wheat was 

 " not due to the absence of available nitrogen as nitrates. ... On the basis of 

 256 nitric nitrogen determinations, indications are that nitrification is still 

 active on the very acid soils of the ammonium sulphate plats." 



The effect of 1.14 in. of rainfall upon the nitric nitrogen and acid content 

 of plat 32, J. W. White {Pennsylvania Sta. Rpt. 1914, pp. 67-70). — Studies of 

 evaporation from a soil during a period of drought and of the capillary move- 

 ment of water-soluble nitrogen and acids or acid salts before and after a heavy 

 rainfall are reported. 



It was found that "the 1.14 in. of rainfall penetrated the soil to a depth of 

 15 in. There was a total loss of 4 per cent of moisture from the surface soil 

 [growing wheat] between August 18 and September 6." The moisture content 

 of the surface 3 in. of soil, as the result of 1.14 in. of rain September 21, in- 

 creased in corn soil from 7.11 to 18.86 per cent, in clover soil from 8.72 to 17.02 

 per cent, and in wheat soil from 6.31 to 16.76 per cent. The corn soil "showed 

 an enormous accumulation of nitrates where corn failed. The difference in 

 nitric nitrogen content of the three areas studied is due for the most part 

 to the presence or absence of vegetation. 



As the result of the rain there was a loss of nitrogen from the corn soil as 

 follows: to 3 in., 80.75 lbs. per acre; to 6 in., 61 lbs. per acre; and to 



