Effect of Partial Removal of Soil Organic Nitrogen with Sodium Pyrophosphate or Sulfuric Acid Solutions on Subsequent Mineralization of Nitrogen1
- George Stanford2
Studies were conducted with Chester loam and Elliott clay loam soils to determine the relationship between amounts of N extracted by Na-pyrophosphate solutions and reduction in capacities of the soils to mineralize N under anaerobic conditions. By employing wide variations in concentration and pH of the extractant, number of extractions, temperature, and extraction time, a broad range was achieved in total amounts of N extracted (40-1,200 ppm). Accompanying reductions in soil N mineralization during 10–11 weeks ranged up to 125–170 ppm, respectively, with the Elliott and Chester soils. A close similarity in susceptibility to mineralization of N extracted from the two soils is indicated, although relative amounts of extractable N differed appreciably.
Acid hydrolysis of Elliott soil with 6N H2SO4 for 12–16 hours reduced N mineralization capacity of the soil to zero. These findings may have important implications in defining criteria for selecting the concentration of an extractant suitable for use in assessing the N status of soils.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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