Humic substances in acid organic soils: modelling their release to the soil solution in terms of humic charge
Humic substances in acid organic soils: modelling their release to the soil solution in terms of humic charge
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DOI：
10.1111/j.1365-2389.1990.tb00227.x
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发表时间：
1990-12
影响因子：
4.2
通讯作者：
E. Tipping;C. Woof
中科院分区：
文献类型：
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作者：
E. Tipping;C. Woof
摘要为了研究腐殖物质（HS）向溶液相的释放，用有机土壤样品进行了分批滴定实验。测量的pH值，溶解的有机碳（DOC）的浓度，和单体（无机+有机）铝的浓度，作为添加的酸或碱的函数。DOC被认为完全是由于HS。结果可以解释的模型，其中土壤被认为是包含两种类型的HS-移动的或潜在的移动的（HSM），和im移动的（HSI）。无机离子的HS的结合使用腐殖酸离子结合模型IV，以前在本实验室开发的计算。模型IV允许计算HS（ZHSM，ZHST）上的电荷;这些电荷主要由H+和A13+的结合决定。溶液中HS的浓度[HSaq]由以下等式给出：其中|公司简介|为ZHM的模量，nHSM为HSM的羧基含量，cHSM为HSM的土壤含量，β为拟合参数，方括号[ ]表示浓度。对于大多数土壤，β值为3时，[HSaq]的测量值和计算值之间的一致性可接受，表明电荷对释放有重大影响。土壤之间的cHSM的优化值有很大的不同，而cHIS的变化只有约2的一个因素。通过模型优化估计的总腐殖酸含量（cHSM+ cHSI）与用NaOH提取土壤的估计值大致一致。
SUMMARY Batch titration experiments were carried out with organic soil samples in order to investigate the release to the solution phase of humic substances (HS). Measurements were made of pH, dissolved organic carbon (DOC) concentration, and the concentration of mono-meric (inorganic + organic) aluminium, as functions of added acid or base. DOC was taken to be entirely due to HS. The results can be interpreted in terms of a model in which the soil is considered to contain two types of HS–mobile or potentially mobile (HSM), and immobile (HSI). The binding of inorganic ions by the HS is calculated using humic ion-binding model IV, previously developed in this laboratory. Model IV allows the charges on the HS (ZHSM, ZHST) to be calculated; these are determined mainly by the binding of H+ and A13+. Concentrations of HS in solution, [HSaq], are given by the equation: where |ZHSM| is the modulus of ZHSM, nHSM is the carboxyl group content of HSM, cHSM is the soil content of HSM, β is a fitting parameter, and square brackets, [ ], indicate concentrations. For most of the soils a value for β of 3 gives acceptable agreements between measured and calculated values of [HSaq], indicating a major influence of charge on release. The optimized value of cHSM differs considerably among soils, whereas cHIS varies by only a factor of about two. Total humic contents (cHSM+ cHSI estimated by model optimization are in approximate agreement with values estimated by extraction of the soils with NaOH.