04 Infill ('lice of Phiiii RrsldiiiH on Nitrogen Fixation 



probability, to the inimical effect of an ever increasing degradation of t he 

 nitrogen coni])ound.s already formed by the bacteria and a conseiiuent 

 accumulation of available nitrogen compounds. 



Definite fixation was also obtained by the use of saccharose, but the 

 addition of molasses to the soil resulted in a loss during six weeks to 

 the extent of 30 per cent, of the nitrogen originally present. This was 

 attributed, though without any definite experimental evidence, to the 

 liberation of free nitrogen from the easily decomposable nitrogen com- 

 pounds in the molasses and to the above mentioned suspension of nitrogen 

 fixation in the presence of such bodies. 



Filter paper and buckwheat straw were without apparent effects 

 when incorporated with the soil, but mustard caused appreciable losses 

 under similar conditions. 



From numerous pot experiments with oats, buckwheat and sugar 

 beet it was evident that the nitrogen stored up by bacterial action readily 

 becomes available for plant growth, and that by the treatment of the 

 soil with sugar, its fertility may be increased to a marked degree. 



These results have been fully confirmed by Remy(i8) who was also 

 able to demonstrate the intimate relationship existing between the 

 supply of magnesia, lime, and mineral manures, and a rich and potentially 

 virulent po])\ihition of Azotobacter in field soils. 



The jjossibility of reproducing on a field scale the conditions obtaining 

 in the above experiments appears at first glance to be somewhat remote, 

 but attention is drawn by Ebbels(io), to the fact that molasses has for a 

 long time been looked upon as a valuable fertiliser for sugar-cane lands 

 in Mauritius. As he was in possession of a large quantity of molasses 

 which could not be disposed of in any other manner a portion of this 

 material was applied to field soil which subsequently was jjlanted with 

 sugar-cane. The soil so treated was found to be not only more productive 

 than that which had not received molasses, but showed five years later 

 a much higher nitrogen content than the control. These results have been 

 corroborated hv Boname(20) who obtained considerable increases of crop, 

 especially in those cases where phosphatic manures were applied in 

 addition to molasses. The effect of treatment was greatest with the 

 first crop, but was found to persist up to the tliird ratoons. Experiments 

 in the Leeward Islands (2i) gave, in three cases out of four, increases 

 varying from 1-8 to 7-7 tons of sugar cane per acre, and in this case 

 also a residual effect was observed. Similar work has also been carried 

 out in Java (22). 



On the other hand, numerous instances are on record, of which those 



