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Models for Predicting Potentially Mineralizable Nitrogen and Decomposition Rate Constants

Author:
Deans, J. R., Molina, J. A. E., Clapp, C. E.
Source:
Soil Science Society of America journal 1986 v.50 no.2 pp. 323-326
ISSN:
0361-5995
Subject:
data collection, equations, mineralization, nitrogen, prediction, soil
Abstract:
Two equations, a single exponential: Nₜ = Nₒ (1 − e⁻ᵏᵗ) and a double exponential: Nₜ = Nₒ S (1 − e⁻ᵏᵗ) + Nₒ (1 − S)(1 − e⁻ᵏᵗ), were used to compare mineralization potentials of soils, where Nₜ is the N mineralized in time (t), Nₒ is the potentially mineralizable N, and S and (1 − S) are the fractions of the labile and recalcitrant organic N compounds decomposing at specific rates h and k, respectively. Data were obtained from the published and unpublished incubation studies of Stanford and Smith (MD), Smith et al. (WA), Deans et al. (MN), El-Haris et al. (US), and Griffin and Laine (CT). The double exponential equation provided the “best fit” of the N mineralization-time (Nₜ/t) curve as determined by the estimated mean square error (MSE). With long-term (>84 d) incubations, Nₜ/t curves for the double exponential equation resulted in an avg MSE of 6 compared with the single exponential equation (avg MSE of 79) for CT, MN, and MD data sets (n = 20). For short-term (≤84 d) incubations, Nₜ/t curves were better estimated by the double exponential (avg MSE = 4, n = 21) than by the single exponential (avg MSE = 12, n = 13) for WA, US, and MN data.
Agid:
6696661