344 Journal of Agricultural Research voi.xvin,No.6 



found to be nitrified amounted to approximately 20 per cent of the total 

 originally present. 



(5) The changes that took place in the nitrogen content of the composts 

 are interesting and seem to indicate that there may have been some fixa- 

 tion of this element from the air, although the results are not conclusive 

 and need verification. 



(6) Sulphofication was found to take place in all the soils examined but 

 varied somewhat according to the type. When 2 5 and 50 mgm. of sulphur 

 were added to 100 gm. of soil, about the same percentage of the total was 

 oxidized in a given time. 



(7) Inoculation of mixtures of rock phosphate and sulphur was not 

 sufficient to promote rapid sulphofication. It required in addition soil 

 or soil water. 



(8) None of the soils tested equaled the Fayette County sample in its 

 capacity to render phosphate soluble when composted with rock phos- 

 phate and sulphur. 



(9) That the production of soluble phosphate was caused by the pres- 

 ence of sulphuric acid generated by the oxidation of the sulphur is demon- 

 strated by the parallel rise in acidity and sulphate. 



(10) The best conditions to promote the reaction are initial inocula- 

 tion, high temperature, thorough aeration, and a fair moisture content. 

 Other contributing factors are the proportions of the different ingredi- 

 ents and probably their mass. 



(11) Taking into account the cost of materials, the compost containing 

 the larger amount of soil and some manure proved more desirable. 



(12) The acid phosphate made by this procedure has just as good a 

 physical condition as the commercial product and would be cheaper if the 

 time and labor involved in its manufacture are disregarded. However, 

 these factors would be the chief causes of objection offered by the con- 

 sumer. With further work on the composition of the mixtures and 

 methods of inoculation it is possible that the process may be simplified so 

 that it may prove of immediate practical application. 



LITERATURE CITED 

 (i) Ames, J. W., and Richmond, T. E. 



1917. FERMENTATION OP MANURE TREATED WITH SULFUR AND SULFATES: 



CHANGES IN NITROGEN AND PHOSPHORUS CONTENT. In Soil Sci., 



V. 4, no. I, p. 79-89. References, p. 88-89. 

 (2) 



1918. EFFECT OF SULFOFICATION AND NITRIFICATION ON ROCK PHOSPHATE. 



In Soil Sci., v. 6, no. 5, p. 351-364. References, p. 364. 

 (3) 



1918. SULFOFICATION IN RELATION TO NITROGEN TRANSFORMATIONS. In 



Soil Sci., V. 5, no. 4, p. 311-321. 

 (4) Brown, P. E., and Johnson, H. W. 



1916. STUDIES IN SULFOFICATION. In Soil Sci., V. I, no. 4, p. 339-362. 

 Literature cited, p. 362. 



