冻融作用对酸化土壤中NH_4~+吸附特性的影响研究

以吉林农业大学长期定位试验田土壤为研究对象,采用室内模拟冻融环境和振荡平衡的方法,探讨冻融作用对NH+4在酸化土壤中吸附特性的影响。结果表明,随着冻融周期的增加,酸化土壤对NH+4的吸附量逐渐减小;冻结时间对酸化土壤吸附NH+4的影响不明显;随着冻前含水量的增加,酸化土壤对NH+4的吸附量逐渐减小,对NH+4的吸附量由大到小排列为:15%25%35%。酸化土壤对NH+4的吸附过程能很好地利用Langmuir方程拟合,冻融作用促进酸化土壤中NH+4的释放,增加了NH+4流失风险。

Effects of Freeze- Thaw Action on Ammonium Absorption Characteristic in Acidified Soils

This study aimed to investigate the effects of freeze -thaw cycles, freeze times and moisture content before -freez- ing on ammonium absorption characteristics in acidified soils by oscillation equilibrium experiment, which was collected and sub- jected to laboratory tests in the Jilin Agricultural University Experimental Station with long - time positioning. Results showed that the ammonium adsorption capacity reduced with the increasing of freeze - thaw cycles ; it had no significant changes under the dif- ferent freeze times ; it reduced with the increasing of moisture content before - freezing, the adsorption capacity of ammonium in different moisture before -freezing treatments soil were arranged by descending order as follows： 15% 〉 25% 〉 35%. Langmuir isotherms was fitted to the adsorbed ammonium in the solution using regression procedure, it gave good fits of the measured data. Freeze - thaw process promoted the release of acidified soil ammonium and increased soil ammonium loss risk.