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Potential Errors in the First‐order Model for Estimating Soil Nitrogen Mineralization Potentials
Author(s) -
Smith J. L.,
Schnabel R. R.,
McNeal B. L.,
Campbell G. S.
Publication year - 1980
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/sssaj1980.03615995004400050025x
Subject(s) - mineralization (soil science) , leaching (pedology) , chemistry , leachate , nitrogen , soil water , mineralogy , environmental chemistry , nitrogen cycle , zoology , soil science , geology , organic chemistry , biology
Nitrogen mineralization incubations were conducted using an aerobic leaching procedure. Two agricultural soils and one forest soil were incubated under aerobic conditions, including periodic leaching of mineral N using either 100 ml of 0.01 M CaCl 2 , 30 ml of 0.01 M CaCl 2 , or 30 ml of 0.05 M CaCl 2 . Mineral and organic N were determined for each leachate. Significant amounts of organic N were leached with the mineral N. Leaching with 30 ml of 0.05 M CaCl 2 removed significantly less mineral N, but the 100 ml 0.01 M of CaCl 2 and 30 ml of 0.01 M CaCl 2 treatments were not significantly different. Although not statistically significant, 30 ml of 0.01 M CaCl 2 consistently leached less organic N than did the other two treatments. Amounts of organic N leached ranged from 13 to 163% of total mineralized N. The mineralization reactions were assumed to follow first‐order kinetics. A comparison was made between root mean square (RMS) deviations of experimental data from a nonlinear least squares (NLLS) equation and the more traditional least squares fit of a straight line to log‐transformed data. The NLLS equation gave a more precise fit to the data and hence more accurate estimates of both the N mineralization potential ( N 0 ) and the mineralization rate constant ( k ) for each soil.