SOIL PHYSICS, CHEMISTRY AND MICROBIOI<OGY 939 



covered immediately. The changes in the soil flora were determined at 

 regular intervals by plate counts and dilution counts. The formation of 

 ammonia and nitrates was also measured at regular intervals. The plants 

 used were buckwheat, clover, corn (maize), mustard, oats and rape. 



These investigations prove that the addition of carbon bisulphide 

 to soil exerts a decided effect on the fauna and flora of the soil. This 

 is caracterized by a temporary reduction in the number of micro- 

 organisms. Ivater, an enormous multiplication of bacteria takes place and 

 an almost parallel increase in production of by-products or soluble nitrogen 

 is noted. The ammonia content seems to follow the curve of bacterial 

 growth and later gives way to larger amounts of nitrate. From the evid- 

 ence it seems that carbon bisulphide in soil produces an increase in soluble 

 compounds of nitrogen and sulphur. 



In Miami soil carbon bisulphide benefited the growth of buckwheat, 

 oats, and mustard. No relation seems to exist between plant stimulation 

 with carbon busulphide and the form of the soluble nitrogen. In non-acid 

 soils carbon bisulphide is most beneficial to sulphur-liking crops such as 

 mustard. In all of the experiments, except acid soils, mustard sho- 

 wed an increased growi:h from the use of carbon bisulphide. Carbon 

 bisulphide in peaty soil greatly benefits the growth of red clover. In sand 

 cultures plus soluble plant food carbon bisulphide favors the growth of 

 certain plants. 



The data show clearly that carbon bisulphide does not act alike in all 

 soils or toward all crops. 



The article concludes with a bibliograph}' of 13 works dealing with this 

 question. 



729 - The Effect of Elemental Sulphur and of Calcium Sulphate on Certain of the H igher 



and Lower Forms of Plant Life. — Pitz W. (Agricultural Ivvpcrimfnt station of Ihtr 

 University of Wisconsin), in /"((/-»«/ of Agricultural Research, yu\. \', 'So. 16, .pp. 771-7S0. 

 Washington, D. C, igi6. 



The problem of sulphur and sulphates in agriculture is still far from 

 being solved, especially as regards their action on micro-organisms. In order 

 to study this phase of the problem, 3 series of experiments were plan- 

 ned : 1) and 2) to note the effect of stilphur and sulphates upon the soil 

 micro-organisms and upon pure ctiltures of legume bacteria ; and 3) to 

 note the effect of sulphur and sulphates en the growth of red clover {Tri- 

 foliuni pratense). For the experiments with mixed cultures fresh soil 

 was used as an inoculum. For legume bacteria all materials were sterilised, 

 and the nutrient medium was inoculated with a pure culture of bacteria from 

 the nodules of red clover. 



The various experiments show that calcium sulphate added to the soil 

 has no perceptible effect on the total number of bacteria growing on gelatine 

 plates, and does not materially affect the production of ammonia or nitra- 

 tes (i). Large quantities of elemental sulphur, on the other hand, reduce the 

 total number of bacteria growing on gelatine plates, while the addition 



(i) Sfc B. I'cb. 1916, Xu. 144. i^"^-) 



