214 EXPERIMENT STATION RECORD. [Vol.40 



dioxid produced each week over a period of several weeks. The materials 

 employed included soy beans, alfalfa, red clover, sugar-beet and rutabaga 

 roots, rape tops, pine needles, oak and maple leaves, white-pine shavings, 

 barley, oats, and buckwheat. The effect of sulphate cf ammonia, nitrate of 

 soda, ammonium phosphate, calcium cyanamid, and acid phosphate upon the 

 decomposition of soy-bean fodder was also studied. The residues from the 

 oxidation experiments were dried and the humus content of each determined. 

 The data are presented in tabular form and illustrated graphically. The con- 

 clusions reached may be summarized as follows: 



Legumes high in nitrogen showed a more rapid rate of decay than straws 

 and litters which were low in nitrogen, nitrogen appearing to influence decom- 

 position. These results are held to indicate that on farms where animal 

 manures are not available the choice of cover crops and green manures is im- 

 portant,, Cyanamid appeared to be toxic to soil bacteria, or at least to arrest 

 the decay of organic matter for two weeks after application. Although com- 

 mercial fertilizers seem to act upon soil humus, decomposing it quite rapidly, 

 they apparently fail to act upon crude organic matter in the same way. 



A list of 44 titles comprising the literature cited is appended. 



Protozoa and the phenomena of reduction in soil, C. A. H. von WOLZOQKII 

 KfiiK. j n.. {Arch. 8uikerindu9. Nederland. Indie, 85 i t917), pp. 1125-1182; Abs. 

 in Intermit. Inst. Agr. [Rome], Internet. Rev. Set. and Pract. Ayr.. 9 (1918), Xu. 

 7. pp. 788-790; Chan. Abs., 1 .' i 1918), No. 23, p. 2647).— The principal biochemi- 

 cal reduction phenomena occurring in the soil and the methods employed for recog- 

 nising them are reviewed, namely "(1 ) the ' reduction index ' (' redUCUegetal '). 

 expressed in cubic centimeters of a dednormal solution of KMn() 4 required to 

 oxidize the quantity of ' ferrous ' iron liberated by 100 gm, of soil y dried at 105° 

 C.) in a sulphurous solution, and (2) the ' ferro-index ' (' ferro-cyfer '), ex- 

 pressed in cubic centimeters of a dednormal solution of KMno. required to 

 oxidize the ferrous iron extracted from 100 gm. of soil (dried at 105°) in au 

 acetic solution." 



Recognizing that protozoa form a biological indicator of the reduction phe- 

 nomena In soils, tlie author attempted to correlate the number of protosea, 

 reduction phenomena, and productive power in a large number of soils from 

 sugar-cane plantations in Java. These investigations showed a relation between 

 the water content, reduction index, ferro-index, and the number of protozoa per 

 gram of soil. By this means be was able to divide the soils into tbree classes, 

 as follows: "(1) Good soils, showing little or no reduction, containing few or 

 do protozoa i from to 50 protozoa per 1 gm. of soil), (2) bad soils, with a higb 

 'reduction index' and many protozoa (50 to 100 or more per gram), and (3) 

 very bad soils, with a very high ' reduction index ' and few or no protozoa 

 (0 to 50 per gram)." 



The occurrence of Azotobacter in cranberry soils, S. A. Waksman {Sctenoe, 

 n. srr., J,8 (1918), Vo. U52. pp. 653, 654 t .—Azotobacter and Actinomyces were 

 found in a limed sandy bog soil having a hydrogen-ion concentration of pH= 

 6.2 to 6.4 but not in the same soil unlimed and having a hydrogen-ion con- 

 centration of pll— 5.4 to 5.6. 



The occurrence of Bacterium lactis viscosum in soil, C. R. FELLERS {Soil 

 Sci.. 5 {1918). No. 6, i>i>. 487, 488). — The author briefly describes observations 

 made on organisms isolated from a Sassafras sandy loam and from a Pens 

 bhaley loam soil known to have been free from applications of cow manure 

 for several years. These are said to have corresponded to written descriptions 

 and laboratory cultures of B. lactis riscusunt. It is thought that the soil may 

 be a natural habitat of the organism. 



