关键词: 苏打盐碱土, 氮, 吸附作用, 硝化作用, 反硝化作用, 动力学

Abstract:

The main component NaHCO₃ was considered as the main factor in Soda saline-alkali soil in order to study the effects of different soda salinization levels on nitrogen adsorption, mineralization, nitrification and denitrification by using laboratory incubation. The results showed that in the experimental conditions with the different NaHCO₃ concentrations, the NH⁺_４-N adsorptions obeyed Langmuir linear adsorption isotherm, while, the N mineralization could be described by the firstorder kinetic equation. With the increasing of NaHCO₃ concentration, the N mineralization potential (M₀) and mineralization rate constant (k_m) decreased from 358.48 mg/kg and 0.088 d^-1 to 337.08 mg/kg and 0.059 d^-1, respectively, and the nitrification could be described by “S” curve model, the maximal rate of nitrification (k_max) decreased from 22.56 to 16.68 mg/(kg·d); the denitrification obeyed zero-order kinetic equation, and there was no significant effect of mixed concentrations variation of NaHCO₃ and Na₂CO₃ on the denitrification rate constant (k_d). NH⁺_４-N adsorption, organic nitrogen mineralization and nitrification were inhibited with NaHCO₃ concentrations increasing in soda saline-alkali soil.

Key words: soda saline-alkali soil, nitrogen, adsorption, nitrification, denitrification, kinetics