Lysimeter Experiments 85 



APPENDIX 



METHODS OF ANALYSIS 



METHODS FOR THE CHEMICAL ANALYSIS OF SOILS 



Preparation of sample. — The soil sample was prepared according to 

 the method described in Bulletin 107 (revised) of the United States Bureau 

 of Chemistry, page 14. 



Moisture. — The moisture content was determined by the official method 

 described in the same publication, page 14. 



Total organic carbon. — The total organic carbon in the soil was de- 

 termined by the optional official method described in the same bulletin, 

 page 234. 



Carbon dioxide. — The carbon dioxide was determined by the official 

 method described on page 19 of the same bulletin. 



Total phosphorus. — The total phosphorus was determined by the 

 provisional method described on page 234 of the publication cited. 



Sulfur. — In determining the sulfur content, 10 grams of the air-dried 

 soil sample was placed in a nickel crucible and thoroly mixed with 25 

 grams of sodium peroxide. The mixture was heated carefully until it 

 was completely fused, and then heated strongly for one hour. The 

 fused mass was transferred from the crucible to a beaker by means of 

 hot water, and the solution was slightly acidified with hydrochloric acid. 

 The beaker was then allowed to stand on the steam bath for about five 

 hours. The contents of the beaker were transferred to a 500-cubic- 

 centimeter graduated flask, cooled, and made up to the mark. After 

 thoro shaking the solution was filtered and an aliquot part of 250 cubic 

 centimeters was treated with ammonium hydroxide to precipitate iron and 

 aluminum. The precipitate of iron and aluminum hydroxide was filtered 

 and thoroly washed, and the filtrate and washings were concentrated to 

 about 200 cubic centimeters. After being slightly acidified with hydro- 

 chloric acid, this solution was heated to boiling, 10 cubic centimeters of 

 barium chloride solution was added slowly, and the mixture was allowed 

 to stand for twenty-four hours. The barium sulfate was filtered, washed, 

 ignited, treated with a drop of concentrated sulfuric acid and about 

 1 cubic centimeter of hydrofluoric acid, and finally ignited over the 

 blast lamp. 



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