APPENDIX B 



DIGESTION PROCEDURE FOR ESTIMATION OF 



TOTAL SULFUR IN SOILS 



REAGENTS 



(All reagents are the same as those for plant tissue digestion.) 

 PROCEDURE 



1. Weigh 5 g of air-dried, screened soil into a 50-ml beaker or 

 ceramic crucible. 



2. Add 10 ml of the magnesium nitrate digestion solution. Allow to 

 stand a few minutes until the soil is thoroughly moist. 



3. Evaporate to dryness on a hot plate. Sample must be completely dry 

 to prevent frothing of the sample when placed in the muffle fur- 

 nace. 



4. Remove from hot plate and place in a muffle furnace. Heat to 

 300°C for 1 hour. Increase temperature to 500°C and muffle for 

 3 additional hours. 



5. Cool. Add 15 ml of the 6 N HC1 and evaporate to dryness on a hot- 

 plate. Be careful that samples do not "bump" resulting in loss cf 

 the sample. 



6. Add 5 ml of 5 N HC1 and dilute to a 50-ml volume. 



7. Shake vigorously and allow suspended material to settle overnight. 

 Filter through a Whatman no. 42 filter paper before determining S 

 turbidimatrically . 



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