Available organic nitrogen in temperate, subtropical, and tropical soils extracted with different solutions

  • Okamoto M
  • Okada K
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Extraction of organic N by chemical solutions has been used to assess the amount of available N in soil. We tested the efficiency of several solutions in extracting organic N from tropical, subtropical and temperate soils. A conventional 0.067 M phosphate buffer successfully extracted organic N from all 23 soils examined. Highperformance size exclusion chromatograms showed a single peak at about 7,800 Da for all phosphate buffer extracts irrespective of soil types. The peak area correlated with the organic N concentration of extracts. Tropical soils had lower retention of organic N than other soils according to the conventional and sequential extraction with phosphate buffer. Organic N extracted with sulfuric acid was significantly (P

Author-supplied keywords

  • Extractable organic nitrogen
  • High-performance size exclusion chromatography (HPSEC)
  • Neutral phosphate buffer
  • Sulfuric acid

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  • Miwa Okamoto

  • Kensuke Okada

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