蒙山茶园土壤组分去除有机质和游离氧化铁后对铝吸附解吸特征的影响

Effect of Removal of Soil Organic Matter and Free Iron Oxide of Soil Component on Characteristics of Aluminum Adsorption-desorption from Tea Garden in Mengshan

以蒙山茶园土壤为研究对象,采用间歇法和振荡平衡法,通过实验室模拟,研究茶园2种土壤(黄壤和紫色土)原土及各粒级组分去除有机质和游离氧化铁后对铝吸附解吸特征的影响。结果表明:(1)分别去除有机质及游离氧化铁后,2种土壤的原土及各粒级组分对铝的静电吸附量均会增加,加之有机质和游离氧化铁对铝均有专性吸附,因而解吸率也均随着有机质和游离氧化铁含量的减少而增加;(2)去除有机质及游离氧化铁后,紫色土原土及各粒级组分分别对铝的等温吸附过程以Freundlich方程拟合效果最佳,而黄壤则以Langmuir方程拟合效果最佳;(3)在茶园土壤中有机质和游离氧化铁是铝离子专性吸附的主要载体,其含量影响土壤对铝的固持能力,从而影响铝的活性及茶树从土壤中吸收活性铝的含量。在茶园土壤管理中,可根据茶树生长所需的铝含量对土壤进行适当改良,以增强土壤对铝的固持能力,从而降低铝的活性,减少茶叶中铝的含量。

Thermodynamics characteristics of aluminum adsorption-desorption of soil and particle-sized fractions with the removal of organic matter and free iron oxide from tea garden in Mengshan were studied with batch and oscillation balance techniques.The results showed that：（1）The electrostatic adsorption amount of aluminum in the two soils and particle-sized fractions increased with the removal of organic matter and free iron oxide.Since soil organic matter and free iron oxide were specific adsorption of aluminum,the desorption rate increased along with the reduction of organic matter and free iron oxide.（2）Freundlich equation was the best equation to fit purple soil and particle-sized fractions of aluminum adsorption with the removal of organic matter and free iron oxide.Meanwhile,Langmuir equation was the best equation to fit yellow soil and particle-sized fractions of aluminum adsorption with the removal of organic matter and free iron oxide.（3）Soil organic matter and free iron oxide were the main adsorption of aluminum ion in tea garden soil.The amount of soil organic matter and free iron oxide affected the retention capacity of the soil for aluminum,thus it affected aluminum activity and the amount of active aluminum absorbed by tea plant.As a result,in tea garden soil management,the soil aluminum content was improved according to the requirement of tea plant growth in order to enhance the retention capacity of the soil for aluminum and reduce aluminum activity and the content in tea leaves.