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Résumé :
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Soil nitrogen mineralization kinetics were studied for eight treatments of two soils in an aerobic long-term (30 wk) incubation experiment. Soil mineral-N (NH4+ and NO3-) in the leachates was measured every week during the first 9 wk and every 2 or 3 wk thereafter. The NH4+ percentage of the mineral-N ranged between 85 and 99% for all treatments in the first week of incubation and remained high (>80%) in several treatments until the end of wk 4. Starting at wk 7, NH4+ concentrations were negligible in all treatments. The net N mineralization rate was 15-24 mg N kg(-1) wk(-1) during the first 4-6 wk and 2-5 mg N kg(-1) wk from wk 8 until the end of the incubation. Four models, (i) a one-component, first-order exponential model (the single model), (ii) a two-component, first-order exponential model (the double model), (iii) a one-component, first-order exponential model including a constant term (the special model), and (iv) a hyperbolic model, were at to the cumulative mineral-N vs time data using a non-linear regression procedure. The goodness of fit of the four models depended on the duration of incubation.
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