Premium
Differentiation of Soil Nitrogen Fractions Using a Kinetic Approach
Author(s) -
Carski T. H.,
Sparks D. L.
Publication year - 1987
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1987.03615995005100020010x
Subject(s) - soil water , extraction (chemistry) , chemistry , kinetic energy , kinetics , nitrogen , environmental chemistry , chromatography , soil science , environmental science , organic chemistry , physics , quantum mechanics
The chemically induced release of NH 4 ‐N from four Delaware soils was monitored over time. The extractants used were 0.02 M KMnO 4 ‐0.5 M H 2 SO 4 at 297 K and 0.01 M CaCl 2 at 368 K. Data were analyzed using first‐order kinetics. The kinetic approach presented does allow direct differentiation of two NH + 4 releasing reactions. Two simultaneous first‐order reactions were needed to describe three of the soils, while a single equation described the remaining soil. The equations were considered to represent the release of NH + 4 from an inorganic and an organic source. Using this approach, estimates of these pools were made and compared with estimates based on traditional batch techniques. Extraction with acid‐KMnO 4 yielded kinetic estimates of the inorganic and organic pools, which exceeded the batch estimates of these pools. Kinetic estimates based on extraction with CaCl 2 were similar to batch estimates of inorganic N, but much less than either acid‐KMnO 4 or batch estimates of organic N. Neither extractant gives direct evidence for the existence of a chemically active organic pool; however, there is indirect evidence for such a pool.