ISSN:
1573-5036
Keywords:
allophane
;
first-order kinetics
;
mineralization
;
nitrate
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract Nitrogen mineralization kinetics of Costa Rican soils developed from volcanic ash were investigated. Two aspects of the aerobic incubation method proposed by Stanford and Smith (1972) were examined: the addition of—N nutrient leaching solution, and air-drying samples prior to incubation. Net cumulative N mineralized over 210 days was analyzed in terms of three kinetic models of N mineralization: single term, first-order (FO); two term, first-order (DFO); and combined first-order, zero-order (FOZ). Net cumulative N mineralization was significantly increased both by air-drying and by—N nutrient solution addition. The effect of air-drying was to induce a ‘flush’ of mineralization during the first 30 to 45 days of incubation, while the effect of the—N nutrient solution was more apparent after that time. The 16 mineralization curves generated were qualitatively similar. The FO model provided the worst fit with the data and deviated from it in a consistent manner. Both the DFO and the FOZ models fit the data closely but the precision of parameter estimation using the DFO model was relatively poor. The first-order term of the FOZ model was interpreted as accounting for pretreatment effects (e.g., air-drying) and the zero-order term as describing the ‘basal mineralization rate’ of the soil. The success of the zero-order term in describing mineralization over long times suggests that incubation methods cannot be used to isolate a ‘mineralizable fraction’ of soil organic N.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02371210
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