1917] SOILS FEETILIZERS. 517 



Stronger inoculation and growtli were produced by using the compost at rates 

 of 100 and 500 lbs. per acre. Crude carbohydrates and basic compounds such 

 as ash and Thomas slag proved very efficient in developing nodule-forming 

 as well as nitrogen-fixing and nitrifying organisms, ash being the most active 

 mineral substance in this respect as indicated by crop response. Properly rein- 

 forced composts furnished all of the nitrogen required for the growth of rye 

 and millet, being more effective in this respect than applications of cyanamid 

 and guano. 



The results reported show that the nodule-forming organisms of alfalfa, red 

 clover, soy beans, and cowpeas may grow well in muck humus having a lime 

 requirement of 5,000 lbs. per acre of 2,000,000 lbs. 



Experiments on " humogen " (bacterized peat), J. A. Voelckeb {Wobuni 

 Expt. Sta. Rpt. 1915, pp. 43-^8, pi. 1; Jour. Roy. Agr. Sac. England, 76 (1915), pp. 

 357-362, pi. 1). — Experiments with oats, peas, and mustard to determine the 

 influence of bacterized peat when added in amounts of 1 part peat to 9 and 19 

 parts of soil are reported. Sodium nitrate in equivalent amounts with reference 

 to nitrogen content was used for comparison. The following conclusions are 

 drawn : 



" Under conditions such as those obtaining in greenhouse cultivation, and 

 where plants can be regularly watered and tended, a good preparation of 

 •humogen' may produce a very marked increase in the growth of the green 

 parts of plants and in the growing of green crops, but it will show practically 

 no benefit in the production of grain." 



Contribution to the knowledge of the nodule bacteria (Bacterium radici- 

 cola) in soils, P. Kalantarov (P. B. Kalantabow) {VQstnik Bakt. Agron. Sta. 

 V. K. Ferrein, No. 21 (1914), PP. 21-52).— The work of others bearing on the 

 subject is briefly reviewed and culture experiments with chernozem and pro- 

 ductive loam soils are reported. 



It was found that nodule bacteria require for their growth a minimum 

 moisture content of about 30 per cent. The growth of B. radicicola increased 

 with greater moisture contents. In general a certain parallelism existed 

 between moisture content of sterilized soil and the number of active nodule 

 bacteria. 



A study of the relation of other soil bacteria to B. radicicola showed that 

 Bacillus mycoides and Bacterium fluorescens liquefadcns, neither In soil nor 

 culture media, exerted any appreciable influence on the growth of Bacterium 

 radicicola. On the other hand. Bacillus mesentericus vulgatus and B. coli 

 communis showed a rather strong antagonism toward Bacterium radicicola. 

 The injurious influence of these organisms was weaker in soil. Inoculation 

 of nodule bacteria into sterilized and unstertlized soils resulted in a slow, 

 weak growth. A slight change in the physiological properties of the noduk- 

 bacteria isolated from the unsterilized soil was observed. 



Studies of a number of bacteria isolated directly from soil led to the con- 

 clusion that only one of these could be placed with certainty in the B. radicicola 

 class. 



The movement of nodule bacteria in sterilized soil was not very marked, 

 averaging only about 0.52 cm. per day. 



Are spore-forming bacteria of any significance in soil under normal condi- 

 tions? H. J. Conn {Jour. Bact., 1 {1916), No. 2, pp. i87-ii»5).— Experiments 

 made at the New York State Experiment Station with three of the spore- 

 forming bacteria always present in soil {Bacillus mycoides, B. cereus, and B. 

 megatherium) are reported, which showed that "when soil infusion was heated 

 before plating at a temperature (75-85° C.) high enough to kill the vegetative 

 forms of bacteria, nearly, if not quite, as many colonies of these spore-forming 



