358 Physiologie. 



phates in the soil vvater than, for example, the Gramineae, owing 

 to the higher protein content of the first group and the special 

 sulphur-bearing bodies abundantly formed in the second group. In 

 this soil, however, there was noticeable Stimulation to seed production 

 in both barley and oats, although there was little or no effect on 

 the development of the quantities of straw. 



In the case of clover the increase in air-dried matter due to 

 calcium sulphate alone was about 23 per cent. With rape the grea- 

 test increase occurred where the calcium sulphate was superimposed 

 upon a complete fertilizer, giving an increase of 17 per cent over 

 the complete fertilizer. A similar order of increase was likewise 

 observed with the radish crop, where the increase above a com- 

 plete fertilization, due to the calcium sulphate addition, averaged 

 9 per cent. 



In general, the calcium sulphate was more effective than the 

 more soluble sodium sulphate. The special influence of sulphates on 

 root development is pointed out They were particularly effected 

 with red clover and rape. In the case of red clover, which was 

 more especially studied, the roots were much elongated where sul- 

 phates entered into the ration. This must result in a more extended 

 feeding area for the plant and, in addition, increase its ability to 

 withstand periods of drought. 



The somewhat common Observation of the benefit of land 

 plaster to this plant can probably be closely correlated with this 

 special effect of sulphates on root development, as well as its high 

 protein character, which would make special demands for sulphur. 



Whether recorded failures in the use of land plaster are to be 

 correlated with wet seasons, a high sulphur content normal to the 

 soil under Observation, or the variety of plants used is a matter for 

 future Observation. 



In these greenhouse experiments elementai sulphur was gene- 

 rally harmful. These harmful results occurred even in the presence 

 of a generous supplj?- of calcium carbonate. These results indicate 

 that elementai sulphur may be toxic through its incomplete oxida- 

 tion to sulphites; toxicity may also arise in the absence of sufficient 

 basic material through the development of acidity from sulphu- 

 ric acid. 



Application of these results to field practice is reserved until 

 more data on field plots are available. Jongmans. 



Wright, C. R., The influence of certain organic materials 

 upon the transformation of soil nitrogen. (Cbl. Bakt. 2. 

 Abt. XLVI. p. 74—79. 1916.) 

 Verf. experimentierte über die Nitrifikation in Gegenwart von 

 frischem und verrottetem Stallmist und Stroh, über die Nitratre- 

 duktion in Gegenwart von frischem und verrottetem Stallmist, 

 von Stroh und von Stärke sowie über die Stickstoffumwandlung 

 in Gegenwart von Stroh, grünem Roggen und grüner Wicke. Er 

 gelangt zu dem Ergebnis, dass, wenn dieses Material in den Boden 

 gebracht wird, ein grosser Teil des löslichen Stickstoffs zu einer 

 unlöslichen organischen Verbindung reduziert wird, und im 

 Boden verbleibt, bis die für den Beginn der Nitrifikation günstigen 

 Bedingungen eingetreten sind. Die unmittelbar nach Düngung mit 

 solchem Material gebauten Kulturpflanzen leiden Mangel an Stick- 



