冻融作用对旱地土壤中不同吸附形态铵根离子的影响（英文）

摘要

[Objective] This study aimed to investigate the effect of freezing and thawing on ammonium adsorption in dryland soil. [Method] The lab simulation test was conducted to study the effect of freeze-thaw action on the total adsorbed amount of ammonium （deionized water extract） and strongly-adsorbed amount of ammonium （0.01 mol/L KCl solution extract） in the dryland soil of Sanjiang Plain. [Result] Compared with linear equation, Freundlich equation could better fit the total adsorbed amount of ammonium in dryland soil （R 2 0.99, SE1.69）. The freeze-thaw action almost had no influence on the total adsorbed amount of ammonium. When the initial concentration of NH 4 ＋ increased from 0 to 200 mg/L, the total adsorbed NH 4 ＋ amount increased from -0.52 to 39.0 mg/kg under freeze-thaw treatment （FTT）, while it increased from -0.70 to 38.5 mg/kg under unfreeze-thaw treatment （UFTT）. However, the strongly-adsorbed amount of ammonium presented linear relationship with the concentration of NH 4 ＋ （R 2 0.99, SE0.54）, and the strongly-adsorbed amount of ammonium increased significantly by FTT. When the initial concentration of NH 4 ＋ increased from 0 to 200 mg/L, the strongly adsorbed amount increased linearly from 2.36 to 28.81 mg/kg for FTT and from -4.25 to 25.12 mg/kg for UFTT. The freezethaw action decreases the concentration of NH 4 ＋ in soil solution when the net strongly-adsorbed NH 4 ＋ in soil is zero., therefore, FTT helped to reduce the leaching of ammonium ions in soil. Freeze-thaw action mainly influenced the exchangeable adsorbed NH 4 ＋ in soil. [Conclusion] This study provides theoretical basis for preventing excessive soil nitrogen from entering into water body and controlling water entrophication.%[目的]探讨冻融作用对土壤中不同吸附形式铵根离子的影响。[方法]通过室内模拟试验,研究了冻融作用对三江平原旱地土壤吸附铵根离子总量（水浸提）、强吸附态量（0.01mol/LKCl溶液浸提）的影响。[结果]冻融处理和非冻融对照处理下,相比线性方程,旱地土壤吸附的铵根离子总量能更好的由Freundlich方程拟合（R2〉0.99,SE〈1.69）。冻融作用对铵根离子的总吸附量基本没有影响：当土壤中加入的NH4＋初始浓度从0mg/L升高到200mg/L时,冻融条件下NH4＋总吸附量从-0.52mg/kg升高到39.0mg/kg;非冻融条件下NH4＋总吸附量从-0.70mg/kg升高到38.5mg/kg。土壤中强吸附态NH4＋的吸附等温线呈线性（R2〉0.99,SE〈0.54）,强吸附态NH4＋的吸附量经过冻融过程后有明显增加,当土壤中加入的NH4＋初始浓度从0mg/L升高到200mg/L时,冻融条件下NH4＋强吸附态含量从-2.36mg/kg呈线性升高到28.81mg/kg;非冻融条件下NH4＋强吸附态量从-4.25mg/kg呈线性升高到25.12mg/kg。由于冻融作用降低了强吸附态NH4＋吸附解吸达到平衡时土壤溶液中NH4＋的浓度,因而有利于降低土壤中铵根离子的淋失。冻融作用主要影响的是以离子交换形式吸附于土壤的NH4＋。[结论]该研究为控制土壤氮素过量输入水体,防治水体富营养化奠定了理论基础。