Dec. 15,1919 



Oxidation of Sulphur in Soils 



337 



Table IX. — Percentage of sulphate sulphur in water-free composts 5 to 10 



Dec. 28. 



Jan. 24. 

 Mar. 7 . . 

 Apr. I . . 

 May 6 . . 

 June 25. 

 Aug. 26. 



Date. 



1917. 



1918. 



1919. 



May 6 



Percentage of added sulphur 

 converted to sulphates 



Heated. 



Stirred. 



No. s. 

 soil and 

 rock phos- 

 phate. 



0.258 



193 

 225 

 249 

 261 

 276 



350 



No. 6, 

 soil, rock 

 phos- 

 phate, 

 and sul- 

 phur. 



0-253 



•367 

 . 422 



•550 

 .676 



•937 

 t-305 



4.227 

 19.91 



Not stirred. 



No. 7, 

 soil and 

 rock phos- 

 phate 



0.258 



177 



169 



'185' 



206 



No. 8. 



soil, rock 

 phos- 

 phate, 



and sul- 

 phur. 



0-253 



304 



399 

 901 



I. 902 

 8.26 



Cold, stirred. 



No. 9, 

 soil and 

 rock phos- 

 phate. 



O. 258 



i-S 



226 

 226 



306 



No. 10, 

 soil, rock 

 pho-J- 

 phate, 

 and sul- 

 phur. 



0.253 



. 200 

 .446 



•751 

 1.230 



3.682 

 17. 19 



Table X. — Parts per million of nitrate nitrogen in water-free composts 5 to 10 



1917. 

 Dec. 24 



1918. 



Jan. 23 



Feb. 27 



Mar. 27 



May I 



June 21 



Aug. 23 



Heated. 



Stirred. 



No. 5, 

 soil and 

 rock phos- 

 phate 



13 



44 



No. 6, 

 soil, rock 

 phos- 

 phate, 

 and sul- 

 phur. 



Not stirred. 



No. 7, 

 soil and 

 rock phos- 

 phate 



No. 8, 

 soil, rock 

 phos- 

 phate, 

 and sul- 

 phur. 



Cold, stirred. 



No. 9, 

 soil and 

 rock phos- 

 phate 



No. 10, 

 soil, rock 

 phos- 

 phate, 

 and sul- 

 phur. 



IJ.XPERIMENTS WITH COMPOSTS OP DIFFERENT AMOUNTS OF SOIIv 



The experiments described below were carried on to test the effect of 

 the sulphofying soil or starter on mixtures of rock phosphate and sul- 

 phur when frequently stirred and kept moistened Avith distilled water, 

 tap water, and soil extract, respectively, and also when variable amounts 



