No. 1, October, 1920] SOIL SCIENCE 41 



men agar gave the lowest counts while the other two media gave about the same results. — 

 Active mold growth was shown in normally cultivated soils by the development of mycelia 

 from small portions of soil when inoculated into agar plates. The presence of mold spores 

 in the soil is believed to be important, as it indicates the previous and future development of 

 active mycelia. There is nothing yet to disprove the idea that molds go through a regular 

 life cycle in the soil. — P. E. Brown. 



283. Gillespie, Louis J. Reduction potentials of bacterial cultures and of water-logged 

 soils. Soil Sci. 9: 199-216. 4 fig- 1920. — A discussion is given of the quantity factor and 

 the intensity factor of oxidation and reduction. Oxidation and reduction potentials are 

 taken as measurements of the intensity factor and the methods used to measure these poten- 

 tials in bacterial cultures and soils are described. Constant reduction potentials, in value 

 close to the hydrogen-electrode potentials, were secured for the facultative anaerobe B. coli, 

 and also for mixed cultures of soil organisms when grown in a deep layer. Measurements of 

 cultures of aerobes showed progressively increasing reduction potentials with lapse of time, 

 but in no case did the reduction potential approach the hydrogen-ion potential as closely as 

 0.3 volt. This may indicate a general difference between anaerobes and aerobes. Soils 

 treated with excess of water became highly reducing as evidenced by their reduction poten- 

 tials. At the same time their hydrogen-electrode potentials changed, the soils becoming 

 less acid. The speed with which the soils became highly reducing varied with the soil, but 

 the addition of 0.1 per cent of dextrose favored the development of reducing conditions. 

 "Sourness" of soils includes more than acidity and this residual unfavorable quality may be 

 a high intensity of reduction. — W. J. Robbins. 



284. Keitt, T. E., and A. W. Murray. A new method for rendering insoluble phosphates 

 available. Georgia Agric. Exp. Sta. Bull. 132 : 47-58. (1919) 1920.— The work was undertaken 

 to determine the influence of composting commercial organic ammoniates, ground rock phos- 

 phate and rich soil, on availability of phosphorus content of ground-rock phosphate and on 

 loss of ammonia from organic ammoniate due to composting. Seven compost heaps were 

 made, cottonseed meal being the source of ammonia. An attempt was made to maintain these 

 heaps at 60 per cent of their maximum water-holding capacity. Heaps were covered to cut 

 down oxygen supply and to reduce the temperature. The tables presented show that part of 

 the phosphoric acid of raw rock-phosphate may be made available by composting with cotton- 

 seed meal, some being changed to a water soluble form. — T. H. McHatton. 



285. Moore, G. T., and J. L. Karrer. A subterranean algal flora. Ann. Missouri Bot. 

 Gard. 6:281-307. 1919. 



FERTILIZATION 



286. Bear, F. E. Adapting fertilizers to soils, farms, crops and climate. Amer. Fertilizer 

 52 13 :72h. 1920. 



287. Conret, G. W. Soils, soil characteristics and their relation to fertilizer require- 

 ments. Amer. Fertilizer 52: 106-114. 1920. 



288. Wenholz, H. Soil improvement for maize. 1. Manures and fertilizers. Agric. 

 Gaz. New South Wales 31: 318-324. 1920.— Discusses potash and lime and residual effect of 

 fertilizers. — L. R. Waldron. 



289. Lewis, C. I., F. C. Reimer, and G. G. Brown. Fertilizers for Oregon orchards. 

 Oregon Agric. Exp. Sta. Bull. 166. 48 p. 3 fig. 1920.— See Bot. Absts. 6, Entry 124. 



FERTILIZER RESOURCES 



290. Bongiovanni, C. Utilizzazione delle acque ammoniacali del gas come concime. 

 [The utilization of ammoniacal waters, from the manufacture of gas, as fertilizer.] Staz. Sper. 

 Agr. Ital. 52: 521-523. 1919. — The description of a method for the preparation of a new fer- 



