Evaluation and Prediction of Forest Soil Acidification in Japan

对日本森林土壤酸化进行了实验和理论研究。从生态学的角度出发，对土壤酸化过程中铝的溶解和离子交换过程进行了专门的研究。对铝(Al)和碱阳离子(Ca、Mg、K、Na)在土壤体系中的动态行为进行了评价和预测，并对用PCV(邻苯二酚紫)柱后衍生化法定量测定Al的离子色谱方法进行了评价。草酸铝络合物和腐殖酸铝络合物在铝溶液的色谱图中有明显的峰。对于草酸盐和铝溶液样品，通过热力学数据预测的物种浓度与离子色谱测定的物种浓度定量一致。利用模拟的酸入射降水或穿透雨，进行了饱和土柱实验。T…的总离子浓度较多的降雨量高于入射降水量。与入射降水相比，模拟穿透雨减少了土壤中阳离子交换的酸中和作用，提高了出水中铝的浓度。在模拟穿透雨中共存的阳离子中，钙离子和钾离子对土壤酸化的影响大于钠离子。森林地被阳离子交换量远高于无机土壤(A层)。结果表明，在土壤溶液pH值较高(4.5~5.15)的条件下，森林地被抑制了无机森林土壤中铝的溶解，并将铝形态转化为有机络合物。SMART模型被简化为只考虑铝的溶解和某些交换反应等物理化学过程。将该结构模型应用于模拟酸入射降水或穿透雨(PH3.3或4.0)的柱实验。结构模型能很好地解释实验结果，特别是在模拟酸雨和穿透雨的情况下。PH3.3。并讨论了各参数值的有效性。利用该模型预测了日本森林土壤化学性质未来100年的变化。较少

Japanese forest soil acidification was investigated by experimental and theoretical approach. From the ecological point of view, Special accounts were taken to the aluminum dissolution and ion exchange process derived from soil acidification. Dynamic behavior of aluminum (Al) and base cation (Ca, Mg, K,Na) in soil systems were evaluated and predicted.An ion chromatographic method in which Al is quantitatively determined via postcolumn derivatization with PCV (pyrocatechol violet) was evaluated for its utility as a method for speciating Al in aqueous solutions. oxalato- and humic aluminum complexes were identified by distinct peaks within chromatograms of Al solutions. Quantitative agreement between predicted species concentrations via thermodynamic data and determined by ion chromatography was obtained for oxalate and aluminum solution samples.Using the simulated acid incident precipitation or throughfall, saturated soil column experiments were carried out. Total ion concentration of t … More hroughfall is higher than that of incident precipitation. As compared with incident precipitaion, Simulated throughfall reduced acid neutralization by cation exchange in soil, and raised Al concentration in effluent. Among co-existing cation in simulated throughfall, the effect of calcium ion and potassium ion on soil acidification were more important than that of sodium ion.Another column experiments, using inorganic forest soil (A-horizon) and forest floor (O-horizon), were carried out. Cation exchage capacity of forest floor was much higher than that of inorganic soil (A-horizon). It was indicated that forest floor retarded the aluminum dissolution in inorganic forest soil and change aluminum species to organic complexes at the condition of relatively high pH (4.5-5.15) in soil solution.SMART Model proposed by De Vries et al.is often referred as a general model for estimate soil acidification. SMART model was simplified only to include the physicochemical processes such as the aluminum dissolution and some exchange reactions. The structured model were applied to column experiments which were carried out by using simulated acid incident precipitation or throughfall (pH3.3 or 4.0). The structured model could explain the experimental results especially at the case of both simulated acid incident precipitation and throughfall. of PH3.3. Also we discussed about the validity of each parameter value. Using this model, future changes of chemical property of forest soil in Japan were predicted for one hundred years. Less