模拟酸雨淋溶下强风化土壤矿物风化计量关系研究

矿物风化计量关系对于定量土壤酸化速率至关重要。我国亚热带地区矿物风化强烈,土壤的酸敏感性高。为获取强风化土壤在矿物风化过程中元素释放特征及其化学计量关系,选取花岗岩发育的富铁土,先用EDTA-乙酸铵溶液洗脱土壤胶体上吸附的盐基离子,然后采用改进的Batch法,将洗脱盐基土壤与未洗脱盐基土壤同时进行模拟酸雨淋溶。结果表明:(1)洗脱盐基土壤与未洗脱盐基土壤的盐基离子(K~+、Na~+、Ca~(2+)和Mg~(2+))释放情况存在显著差异,洗脱盐基后土壤在淋溶中释放的盐基来源为矿物风化,释放缓慢而平稳;(2)未洗脱盐基土壤在淋溶初期,盐基的释放量较大,随着淋溶的进行,释放量迅速下降,淋溶后期的释放速率与洗脱盐基土壤接近,这说明未洗脱盐基土壤在淋溶初期释放的盐基主要来源于阳离子交换过程,后期则主要来源于风化过程;(3)洗脱盐基土壤和未洗脱盐基土壤经酸雨淋溶释放的各盐基化学计量关系(K~+∶Na~+∶Ca~(2+)∶Mg~(2+))以及盐基离子与硅的化学计量关系(BC∶Si)差异较大,由于未洗脱盐基土壤受到阳离子交换的影响,因此只有洗脱盐基土壤的矿物风化计量关系可以作为定量估算土壤酸化速率的依据。     

模拟酸雨淋溶下不同母质发育雏形土矿物风化中的盐基离子与硅计量关系

土壤矿物风化过程中释放的盐基离子(BC)与硅(Si)的比值(BC︰Si)是定量评估土壤矿物风化对土壤酸化过程缓冲作用的基础,是准确估算当前环境下土壤酸化速率的依据。本研究以云母片岩、片麻岩和安山岩3种母质发育的湿润雏形土为研究对象,测定了其土壤物理、化学和矿物学性质。通过洗脱实验除去土壤交换性盐基以消除土壤胶体吸附的交换性盐基离子对矿物风化计量关系的影响,再利用模拟酸雨淋溶实验,采用Batch方法获取3种不同母质发育土壤的盐基离子和硅的释放量,进一步估算BC︰Si值。结果表明,由于母岩不同,土壤黏粒、pH、有机质、交换性盐基(K⁺、Na⁺、Ca²⁺和Mg²⁺)、阳离子交换量(CEC)和土壤矿物含量存在差异。在模拟酸雨淋溶实验条件下,未洗脱盐基土壤的BC︰Si值为洗脱盐基土壤的3倍以上,因此只有洗脱土壤交换性盐基才能获得来自风化过程的BC︰Si值。同一母质发育土壤的腐殖质表层(Ah)BC︰Si最小,母质层(C)最大。不同母质发育土壤的BC︰Si值表现为：片麻岩>云母片岩>安山岩,土壤中斜长...     

模拟酸雨对砖红壤盐基离子迁移和释放的影响

对发育于玄武岩的砖红壤进行了室内模拟酸雨淋溶试验,结果表明：（1）酸雨淋溶土壤会引起土壤盐基离子的大量淋失。以土壤中的K＋最易于淋失,Ca^2＋、Mg^2＋的淋失量最大。酸雨pH愈低,Ca^2＋、Mg^2＋、K^＋的迁移量愈大。酸雨淋溶土壤的时间越长,盐基离子的迁移量越大。（2）土壤经≥5d的酸雨淋溶后,土壤交换性盐基离子的含量均随淋溶时间的增加而减少。酸雨的pH不同,则土壤交换性盐基离子所受的影响不同。（3）与原土壤相比较,短期（≤5d）的酸雨淋溶,可使土壤交换性Ca^2＋、K^＋以及强酸性（pH≤3.0）酸雨淋溶的交换性Mg^2＋增加;土壤被酸雨较长时间（≥10d）淋溶后,则会降低土壤交换性Ca^2＋、Mg^2＋、K^＋的含量;不同时间的酸雨淋溶,均会降低土壤交换性Na^＋的含量。（4）土壤经酸雨淋溶后,某些矿物会发生风化,释放出盐基离子,也会使部分交换性盐基离子转成非交换态。     

生物结皮发育对风沙土盐基离子释放和矿物风化的影响

为探明生物结皮发育对风沙土盐基离子释放和矿物风化的影响,以进一步明确生物结皮的风化成土作用。以典型风沙土上发育的生物结皮为对象,通过模拟淋溶试验比较不同类型生物结皮(藻结皮、藻—藓混生结皮和藓结皮)覆盖土壤的盐基离子释放规律,探究盐基离子释放量随淋溶液pH的变化趋势,以及量化生物结皮覆盖土壤的矿物风化速率。结果表明:矿物风化反应阶段不同种类盐基离子的淋出量均较为平缓,生物结皮覆盖土壤的各盐基离子总淋出量表现为Ca²⁺＞K⁺＞Mg²⁺＞Na⁺,其中藻结皮覆盖土壤的盐基离子总淋出量最高,比无结皮、混生结皮和藓结皮分别增加了112.0%,31.2%,27.1%。淋溶液pH显著影响盐基离子的淋溶释放,且其作用程度因离子种类和结皮类型而异。生物结皮覆盖提升了土壤的易风化矿物含量、风化程度和速率,藻结皮、混生结皮和藓结皮覆盖土壤的风化速率相比无结皮分别提升了61.2%,27.1%,152.6%,并且风化速率随淋溶液pH降低而提升。综上,生物结皮能显著促进风沙土矿物风化,其对风沙土改良和修复具有积极意义。     

三峡库区2种土地利用方式下土壤盐基离子及碳氮含量对氮添加的响应

为探究三峡库区2种土地利用方式下土壤交换性盐基离子及土壤碳氮含量对氮添加的响应,以湖北省秭归县的林地和果园土壤为研究对象,进行室内土柱淋溶模拟试验,研究4种不同氮添加量(0,50,120,200 kg/(hm²·a))下,土壤中交换性Ca²⁺、Mg²⁺、Na⁺、K⁺以及NO₃^--N、DOC的变化。结果表明：随着氮添加量的增加,林地土壤中的交换性盐基离子淋失量显著增加(p<0.05),而果园土壤中的交换性盐基离子淋失量无显著变化,且林地土壤中交换性盐基离子淋失总量与各盐基离子淋失量均高于果园土壤;经N1、N2、N3处理后,与对照组(N0)相比,林地土壤中的交换性盐基离子淋失总量分别增加1.78%,4.45%,8.49%,且NO₃^--N淋失量分别增加89.21%,77.73%,157.25%,说明氮添加通过加剧土壤中NO₃^--N的淋失带走土壤中交...     

几种低分子量有机酸淋溶对土壤铝、硅及盐基离子淋失的影响

采用50cm原状土柱进行模拟淋溶实验,比较研究了模拟酸雨和几种低分子量有机酸对红壤Al、Si及盐基离子淋失的影响。结果表明,模拟酸雨淋洗后土壤中有极少量的Al和一定量的Si及盐基离子淋出。与去离子水对照相比,pH3.5和pH4.5模拟酸雨处理Si的淋出总量分别增加了6.52%和3.26%;K 、Na 、Ca2 和Mg2 等盐基离子淋出量增加了2.41%~96.80%。100μmol/L的柠檬酸、苹果酸和草酸处理Al、Si的淋出量与模拟酸雨处理相差不大,而10mmol/L的柠檬酸、苹果酸和草酸处理则比模拟酸雨处理有显著的增加。有机酸淋洗后淋出液中各盐基离子含量均要高于模拟酸雨处理,盐基离子淋出总量是模拟酸雨处理的1.58~9.27倍。实验结果说明低分子量有机酸在酸化土壤方面比酸雨有更大的威胁。由于盐基离子的大量淋失,模拟酸雨和有机酸淋洗后淋出液pH均要高于原淋洗液pH。     

低分子量有机酸对褐土盐基离子淋失的影响

低分子量有机酸能够活化土壤养分,同时也能够与钙、镁形成沉淀,进而影响着养分物质转化过程。为进一步探讨低分子有机酸对石灰性土壤盐基离子的影响,本文采用土柱模拟淋溶试验,以褐土为研究对象,研究了柠檬酸和草酸对褐土盐基离子淋失的影响。研究结果表明:添加两种低分子量有机酸淋洗土壤后,土壤淋出液的电导率均增大,K~+、Na~+、Ca~(2+)、Mg~(2+)的淋失总量均增加,最高达到27.734 mmol,为对照的14倍,作用效果柠檬酸草酸。柠檬酸处理显著降低了土壤的pH,最多比对照降低了0.9个pH单位。且持续时间较长,至处理后的第30天,仍对Ca~(2+)、Mg~(2+)表现出较强的活化作用。对于同一种低分子有机酸来说,酸的浓度越高,活化能力越强。研究结果将为石灰性土壤合理施肥提供一定的理论依据。     

酸化环境对紫色母岩风化产物交换性盐基离子及其酸缓冲容量的影响

为了分析研究酸化环境对紫色母岩风化产物交换性盐基离子及其酸缓冲容量的影响规律。本研究以侏罗纪紫色岩层中的遂宁组(J3s)、沙溪庙组(J2s)和蓬莱镇组(J3p)为研究对象，设置pH分别为2.5、3.5、4.5、5.6等4个酸性环境，以及去离子水（pH=7.0）为对照处理（CK），采用循环浸泡试验和模拟淋溶试验，研究酸性环境对紫色母岩风化产物特征的影响。结果表明，通过酸化环境处理后，3组紫色母岩风化产物交换性盐基离子及其总量均随酸化环境的pH降低而减小，且3组紫色母岩风化产物的酸缓冲容量与其交换性K+、Na+、Ca2+、Mg2+含量以及交换性盐基总量均呈极显著正相关关系(P<0.01)。以pH =7.0 (CK)处理为对照，循环浸泡处理后的遂宁组(J3s)、蓬莱镇组(J3p)和沙溪庙组(J2s)风化产物中交换性盐基总量的减小幅度分别为8.75%～18.21%、10.83%～23.18%和5.85%～18.41%。而且模拟淋溶24次后，遂宁组(J3s)、沙溪庙组(J2s)和蓬莱镇组(J3p)风化产物中交换性盐基总量较模拟淋溶12次时分别减小为1.77%～24.85%、8.99%～25.75%和8.05%～25.66%。此外，在同一酸度处理下，风化产物中的交换性盐基离子均表现为Ca2+> Mg2+> Na+> K+。本试验中淋溶处理下风化产物酸缓冲容量、交换性盐基离子及盐基总量低于浸泡处理。可见，丘陵地带坡面的矿物或养分的迁移以淋溶作用为主，平地的矿物或养分的迁移以浸泡作用为主。因此，酸沉降可能在一定程度上加速坡面土壤侵蚀的发生，进而导致平原化进程的加速。     

磁化微咸水灌溉对土壤交换性盐基离子组成的影响

在淡水资源贫乏的土壤盐渍化地区,通过对磁化微咸水灌溉后土壤交换性盐基离子组成和水溶性盐分的测定分析,探讨地下微咸水灌溉对土壤交换性盐基离子组成的影响。结果表明:(1)微咸水灌溉中土壤交换性Mg~(2+)、K~+、Na~+降低0.7%~25%,其交换性盐基饱和度(BSP)降低7.9%~32.4%;交换性Ca~(2+)和交换性盐基总量(TEB)提高6.7%~7.9%,BSP Ca~(2+)(Ca~(2+)在交换性盐基中所占百分比)提高1.5%~3.0%;(Ca~(2+)+Mg~(2+))/TEB、Ca~(2+)/K~+、Ca~(2+)/Mg~(2+)和Mg~(2+)/K~+均增加0.6%~51%,K~+/TEB则降低13.2%~31.3%;(2)磁化微咸水灌溉后,土壤交换性K~+、Ca~(2+)、TEB和BSP K~+、BSP Ca~(2+)含量提高13.2%~31.3%;交换性Na~+、Mg~(2+)和BSP Na~+、BSP Mg~(2+)均降低为9.3%~56.5%,呈显著差异水平(P0.05),且各交换性盐基离子平均含量大小依次为Ca~(2+)Mg~(2+)Na~+K~+;Ca~(2+)/K~+、Ca~(2+)/Mg~(2+)、(Ca~(2+)+Mg~(2+))/TEB、K~+/TEB均提高3.7%~47.8%,Mg~(2+)/K~+则降低47.8%~55.4%;(3)土壤交换性盐基离子与水溶性盐基离子K~+、Na~+、Ca~(2+)、Mg~(2+)之间总体呈极显著相关(P0.01),与(Ca~(2+)+Mg~(2+))/TEB均表现为极显著相关(P0.01)。综上所述,磁化微咸水灌溉改变了土壤盐基离子的交换特性和离子组成,对降低土壤盐渍化地区长期应用微咸水灌溉产生的土壤盐分积聚有良好的作用。     

热带亚热带酸性土壤硝化作用与氮淋溶特征

通过室内好气培养和土柱模拟淋洗培养试验,研究了氨基氮肥加入对热带亚热带4种不同性质和利用方式酸性土壤硝化、氮及盐基离子淋溶、土壤及淋出液酸化的影响。4种土壤分别为采自花岗岩发育的海南林地砖红壤(HR)、玄武岩发育的云南林地砖红壤(YR)、第四纪红黏土发育的江西旱地红壤(RU)和第四纪下蜀黄土发育的江苏旱地黄棕壤(YU)。结果表明:4种土壤硝化作用大小表现为YURUYRHR。HR主要以可溶性有机氮(DON)和NH_4~+-N形态淋失,YU土壤的氮淋溶形态以NO_3~–-N为主,YR和RU土壤的氮淋溶形态NO_3~–-N、NH_4~+-N和DON兼而有之。盐基离子总淋失量与NO_3~–-N淋失量显著正相关,但各盐基离子淋失由于离子本性和土壤性质差异并不完全一致。Ca~(2+)在缓冲外源NH_4~+-N硝化致酸和平衡NO_3~–-N淋失所带负电荷过程中起重要作用。在阳离子交换量小、盐基饱和度低的土壤(如RU土壤),外源NH_4~+-N的硝化和淋失不仅导致盐基离子淋失,而且引发NH_4~+-N、甚至是H~+淋失。综上,热带亚热带地区土壤上外源氮输入的增加可能会在更短的时间内导致氮素向系统外的流失,引发环境问题。     

氮肥施用对砖红壤硝态氮和盐基离子淋失特征的影响

氮肥品种的合理选用对作物增产增收、 土壤酸化改良有重要的影响。本文以海南省海口市观澜湖采集的砖红壤为研究对象,采用室内土柱模拟试验,对尿素、 硝酸铵和硫酸铵3种氮肥处理下砖红壤硝态氮及盐基离子（Ca2+、 Mg2+、 K+、 Na+）淋失特征进行了研究。结果表明, 1）硝态氮累积淋溶量表现为硫酸铵硝酸铵尿素N0,且硝态氮的淋溶量与施肥量呈正相关关系,整个淋溶过程中硝态氮累积淋溶量（y kg/hm2）与施肥量（x kg/hm2）之间满足线性方程 y=3.3064x+315.74（R2=0.8848）; 2）尿素、 硝酸铵、 硫酸铵处理整个淋溶过程的盐基离子淋溶量均表现为 Ca2+Mg2+K+Na+,且盐基离子淋溶总量（kg/hm2）表现为硫酸铵（1821.12）硝酸铵（1080.27）尿素（872.24）N0（417.23）; 3）砖红壤盐基离子迁移速率表现为硫酸铵（26.28%）硝酸铵（13.37%）尿素（11.78%）,尿素、 硝酸铵和硫酸铵处理分别以线性方程 y=0.1178x+123.18（R2=0.9121）、 乘幂方程 y=15.634x0.4423（R2=0.9259）和对数方程 y=128.38e0.0007x（R2= 0.9244）的拟合度最高。     

Long Term Changes of Base Cation Pools in Soil and Biomass in a Beech and a Spruce Forest of Southern Sweden

During the past 60 years there has been a considerable decline in pH in mineral soil beneath spruce and beech stands at Tönnersjöheden Experimental Forest in south-west Sweden. In this report an attempt is made to estimate the corresponding declines in base cation pools. The exchangeable storage of Na, K, Ca and Mg in soil, down to 70 cm depth, is calculated to have decreased by 57–60 per cent for beech and by 56–74 per cent for the spruce stands during the period 1927–1984. The calculated cation depletions are compared with estimated nutrient uptake in biomass, base cation release by weathering and leaching losses due to percolation of strong mineral acids and organic anions during the period. The biological acidification may explain about 50–60 per cent of the total losses of base cations from soil, the cation accumulation in biomass then explain 41–43 per cent units for beech and 34–45 per cent units for spruce. The estimated losses of base cations due to acid rain correspond to an amount of cations similar to that accumulated in the spruce biomass during one generation.     

Base Cation Supply in Spruce and Beech Ecosystems of the Strengbach Catchment (Vosges Mountains, N-E France)

In spruce and beech stands, mineral budgets for a rotation period were calculated from measured element fluxes. The release of base cations by mineral weathering was calculated with the steady state soil chemistry model PROFILE. The calcium release rate by weathering of the mineral fine earth was extremely low. For the period of one rotation, mineral weathering cannot provide enough Ca to compensate timber harvesting and leaching. Forest sustainability depends strongly on the amounts of Ca gained from deposition and lost by biomass removal. Magnesium was supplied by atmospheric deposition and mineral weathering. Calculated weathering rates were close to present soil losses. However, as the model assumes that all dissolution reactions are congruent, the computed release rate of Mg from illite might be too high. Main inputs of K to the soil solutions were primarily attributed to canopy leaching and litterfall in upper horizons and to mineral weathering in deeper horizons. The cation budget of the beech stand was much more equilibrated than that of the spruce stand. Given possible changes in silviculture and deposition chemistry, the sustainability of the present stands is rather improbable with respect to their mineral supply.     

Effects of enhanced supplies of nitrogen and sulphur on rhizosphere and soil chemistry in a Norway spruce stand in SW Sweden

Rhizophere and bulk soil chemistry were investigated in a Norway spruce stand in SW Sweden. The rhizosphere and bulk soil chemistry in water extracts in control plots (C) and plots repeatedly treated with ammonium sulphate (NS) were compared. Treatment regime was started in 1988. Cylindrical core samples of the LFH-layer and mineral soil layers were collected in 1992 and used for water extract analyses. Samples of soil from LFH-layer and mineral soil layers were taken in 1991 and 1993 for determination of CEC and base saturation. Soil pH and NH₄-N, NO₃-N and SO₄-S, Al, Ca, K and Mg concentrations in water extracts were measured for rhizosphere and bulk soils. The pH-values of bulk and rhizosphere soils in NS plots decreased compared with those in control plots, whereas concentrations of NH₄-N, NO₃-N, SO₄-S, base cations and Al in water extract increased. In both bulk and rhizosphere soils the concentration of NH₄-N was much higher than that of NO₃-N. A significant difference in the pH and Mg concentration of bulk and rhizosphere soil between the treated and control plots was found only in the 0–10 cm layer. For all layers, there was a significant difference in NH₄-N concentrations in the bulk and rhizosphere soil between the NS treatment and control plots. Concentrations of exchangeable base cations and the base saturation level in the LFH-layer decreased in the NS plots. The concentration of extractable SO₄-S increased in the NS plots. The NS treatment enhanced the amount of litter in L-layer, owing to increases in needle biomass and litterfall but led to losses of base cations, mainly K and Mg, from LFH-layer. It was concluded that the NS treatment displaced cations from exchangeable sites in the LFH-layer leading to higher concentrations of these elements in both rhizosphere and bulk soil.     

The Weathering of Mineral Soil by Natural Soil Solutions

Chemical weathering is an important neutralisation process and sourceof cations in forest soil. The presence of dissolved organic matter in the soil solution can have a considerable influence on weathering release. The aim of this study is to compare the weathering potentialof natural soil solutions, collected from Norway spruce, Scots pine and birch sites, to release Al, Ca, Mg, K, Na, and Si from the fine fraction in the C horizon of a podzol. Residual organic matter in the mineral soil was removed with H₂O₂. The <0.06 mm fraction of the mineral soil was suspended in soil solution, collected from the three sites, for 11 days with continuous agitation. Ultrapure water was used as a control. The pH of the suspensions was maintained at 5.4 by bubbling with CO₂. The initial mean DOC concentrations in the soil solutions were 65, 56 and 40 mg L^-1 for the spruce, pine and birch sites, respectively. The presence of DOM in the soil solution did not significantly enhance the capacity to weather mineral soil material, and no systematic differences were found between the three sites. However, Al release from the mineral soil was slightly higher in the soil solutions containing DOM compared to the control solution with no DOM. The proportions of DOM fractions capable of enhancing weathering were comparable with those reported in earlier studies. The weathering of metals was found to be primarily due to pH-driven processes. The lack of considerable weathering enhancement by DOM could be due to the fact that the cation-binding sites of the organic ligands were already saturated by e.g. Al and Fe in the soil solution derived from these podzolic, Al- and Fe-rich soils.     

Simulation of solution chemistry in an acidic forest soil

The computer simulation model SOILEQ was used to estimate soil solution chemistry over a 7 week period from October 3 to November 14, 1988 in the soils of a sugar maple forest located near St. Hippolyte, Quebec, Canada. Model parameters for pH-dependent CEC and exchangeable cations were calculated from laboratory measurements while soil solution chemistry, including Al solubility, at the start of the simulation was taken from values obtained from lysimeter samples. Model predictions were compared with values obtained from 12 sets of soil solution collectors over the same time period. Predicted values of Ca, Mg and K in the mineral soil horizons at 25-, 75- and 125-cm depths generally fall within the 95% confidence interval of the median for the measured values. Simulated values of pH and inorganic Al are not as close to the measured values. Some error due to drift is apparent, most notably for base cations in solutions leaving the organic surface horizons, and may be attributable to decomposition of organic matter, not included in the simulation model. The results indicate that other mechanisms that release H* (nitrification, for example) and base cations (mineral weathering or mineralization of organic matter) need to be considered.     

Liming Decreases the Vertical Mobility of Potassium in Acidic Soils

Liming increases soil negative charges and thus affects the chemical equilibrium of cations between the solid phase and the soil solution with consequences for the mobility of cations. The effects of lime and potassium chloride (KCl) addition on the vertical movement of potassium (K), calcium (Ca), and magnesium (Mg) were investigated in two Brazilian soils. The experiment was carried out in leaching columns. Treatments included a combination of rates of KCl (0, 50, 100, and 200 mg kg^?1 K) and acidity levels (without and with liming). Seven water percolations (400 mL per column) were performed at weekly intervals, totaling an equivalent to 357 mm of rain. Raising the soil pH decreased the leaching of K, in both soils, up to 50% because of the increase of its electrostatic adsorption on created negative charges. Addition of KCl increased the percolation of K, Ca, and Mg proportionally to the rate applied, and it was more efficient than calcium carbonate to percolate Ca in both soils. Liming must be taken into consideration when K leaching or plant needs of K are estimated in predominantly variable-charge soils.     

Stoichiometry of base cations and silicon during weathering of a deep soil profile derived from granite

Evaluation of the stoichiometry of base cations (BCs, including K⁺, Na⁺, Ca²⁺, and Mg²⁺) and silicon (Si) (BCs:Si) during soil mineral weathering is essential to accurately quantify soil acidification rates. The aim of this study was to explore the differences and influencing factors of BCs:Si values of different soil genetic horizons in a deep soil profile derived from granite with different extents of mineral weathering. Soil type was typic acidi-udic Argosol. Soil samples were collected from Guangzhou, China, which is located in a subtropical region. To ensure that the BCs and Si originated from the mineral weathering process, soil exchangeable BCs were washed with an elution treatment. The BCs:Si values during weathering were obtained through a simulated acid rain leaching experiment using the batch method. Results showed that soil physical, chemical, and mineralogical properties varied from the surface horizon to saprolite in the soil profile. The BCs:Si values of soil genetic horizons during weathering were 0.3-3.7. The BCs:Si value was 1.7 in the surface horizon (A), 1.1-3.7 in the argillic horizon (Bt), and 0.3-0.4 in the cambic (Bw) and transition (BC) horizons, as well as in horizon C (saprolite). The general pattern of BCs:Si values in the different horizons was as follows: Bt > A > Bw, BC, and C. Although BCs:Si values were influenced by weathering intensity, they did not correlate with the chemical index of alteration (CIA). The release amounts of Si and BCs are the joined impact of soil mineral composition and physical and chemical properties. A comprehensive analysis showed that the BCs:Si values of the soil derived from granite in this study were a combined result of the following factors: soil clay, feldspar, kaolinite, organic matter, pH, and CIA. The main controlling factors of BCs:Si in soils of different parent material types require extensive research. The wide variance of BCs:Si values in the deep soil profile indicated that H⁺ consumed by soil mineral weathering was very dissimilar in the soils with different weathering intensities derived from the same parent material. Therefore, the estimation of the soil acidification rate based on H⁺ biogeochemistry should consider the specific BCs:Si value.