暗棕壤中低分子有机酸的吸附与生物降解研究

低分子有机酸在森林生态系统中普遍存在,在根际和多种成土过程中发挥重要作用,但有机酸发挥作用的能力和效率与其在土壤中的吸附与降解等行为关系密切。本文研究了草酸、柠檬酸和苹果酸等低分子有机酸在森林暗棕壤A1层和B层的吸附及生物降解行为,结果表明,低分子有机酸加入到暗棕壤后迅速被土壤固相颗粒所吸附,其中对草酸的吸附远强于柠檬酸和苹果酸,三种低分子有机酸在暗棕壤A1层的吸附率强于B层;草酸、柠檬酸和苹果酸加入到森林暗棕壤后还能迅速被微生物降解,其中对草酸的降解远低于柠檬酸和苹果酸,暗棕壤对草酸较强的吸附作用可能是其生物降解率较低的主要原因,且三种低分子有机酸在A1层暗棕壤中的生物降解率高于B层。

Sorption and Biodegradation Behavior of Organic Acids with Low Molecular Weight in Dark Brown Forest Soils

Organic acids with low molecular weight are ubiquitous in forest ecosystems and are believed to play a key role in many rhizosphere and pedogenic processes.however.their efficiency is likely to depend on their susceptibility to sorption and biodegradation.The sorption reactions and biodegradation rates of three organic acids(Citrate,Malate and Oxalate)were studied as a function of dark brown forest soil depth(A1 and B horizons)in forest litters and leachates.The results showed these organic acids were quickly absorbed by the solid phase.The strength of anion sorption followed the series:oxalate>malate >citrate.And sorption capacity of A1 horizon was much higher than that of B horizon.three organic acids could be degraded by microbe in the soil.Malate and citrate were rapidly biodegraded in A1 and B horizons,in contrast oxalate appeared to be resistant to microbial degradation.And the rates of microbial degradation of three organic acids were higher in A1 horizon soil.