Sorption and desorption characteristics of sulfamethazine in three different soils before and after removal of organic matter

Organic matter (OM) is the most critical factor in controlling the sorption-desorption of SMZ in soil, however, few studies have explored the effects of OM removal on these important behaviors among different soils. Batch experiments were conducted to investigate the sorption and desorption characteristics of SMZ in three different soils: fluvo-aquic soil (FS), paddy soil (PS), and red soil (RS). The SMZ sorption in the evaluated soils was dominated by physisorption. The SMZ sorption capacities of FS and PS, which had a relatively higher OM content than RS, were higher than that of RS. The SMZ sorption in FS was dominated by linear partitioning. In contrast, the SMZ sorption in PS and RS was mainly nonlinear surface adsorption. After OM removal, the SMZ sorption capacity was significantly reduced in FS but increased in PS and RS. Furthermore, OM removal restrained the sorption intensity of SMZ in soils. Relatively higher OM and clay contents inhibited the SMZ desorption in FS and PS. The strong negative desorption hysteresis of SMZ in the three soils indicated that SMZ was able to move into the soil solution, thereby posing a risk to humans. Taken together, the findings of this study showed that OM indeed plays an important role during SMZ sorption-desorption in soil.     

Adsorption and Desorption of Copper in Pasture Soils

Abstract

Copper (Cu) is bound strongly to organic matter, oxides of iron (Fe) and manganese (Mn), and clay minerals in soils. To investigate the relative contribution of different soil components in the sorption of Cu, sorption was measured after the removal of various other soil components; organic matter and aluminum (Al) and Fe oxides are important in Cu adsorption. Both adsorption and desorption of Cu at various pH values were also measured by using diverse pasture soils. The differences in the sorption of Cu between the soils are attributed to the differences in the chemical characteristics of the soils. Copper sorption, as measured by the Freundlich equation sorption constants [potassium (K) and nitrogen (N)], was strongly correlated with soil properties, such as silt content, organic carbon, and soil pH. The relative importance of organic matter and oxides on Cu adsorption decreased and increased, respectively, with increasing solution Cu concentrations. In all soils, Cu sorption increased with increasing pH, but the solution Cu concentration decreased with increasing soil pH. The cumulative amounts of native and added soil Cu desorbed from two contrasting soils (Manawatu and Ngamoka) during desorption periods showed that the differences in the desorbability of Cu were a result of differences in the physico‐chemical properties of the soil matrix. This finding suggests that soil organic matter complexes of Cu added through fertilizer, resulted in decreased desorption. The proportions of added Cu desorbed during 10 desorption periods were low, ranging from 2.5% in the 24‐h to 6% in the 2‐h desorption periods. The desorption of Cu decreased with increasing soil pH. The irreversible retention of Cu might be the result of complex formation with Cu at high pH.     

The effect of soil type on phosphorus sorption capacity and desorption dynamics in Irish grassland soils

Abstract. The phosphorus (P) sorption and desorption dynamics of eleven major agricultural grassland soil types in Ireland were examined using laboratory techniques, so that soils vulnerable to P loss might be identified. Desorption of P from soil using the iron-oxide paper strip test (Pfeo), water extractable P (Pw) and calcium chloride extractable P (Pcacl₂) depended on soil P status in all soils. However, soil types with high organic matter levels (OM), namely peat soils (%OM >30), had lower Pfeo and Pw but higher Pcacl₂ values compared to mineral soils at similar soil test P levels. Phosphorus sorption capacity remaining (PSCr) was measured using a single addition of P to soils and used to calculate total P sorption capacities (PSCt) and degree of P saturation (DPS). Phosphorus sorption capacities correlated negatively with % OM in soils indicating that OM may inhibit P sorption from solution to soil. High organic matter soils exhibited low P sorption capacities and poor P reserves (total P, oxalate extractable P) compared to mineral soils. Low P sorption capacities (PSCt) in peat soils were attributed to OM, which blocked or eliminated sorption sites with organic acids, therefore, P remained in the soil solution phase (Pcacl₂). In this work, peat and high organic matter soils exhibited P sorption and desorption characteristics which suggest that these soils may not be suitable for heavy applications of manure or fertilizer P owing to their low capacities for P sorption and storage.     

Influence of Increasing Soil Copper Concentration on the Susceptibility of Phosphomonoesterase and Urease to Heat Disturbance

The sorption of chromium (Cr) species to soil has become the focus of research as it dictates the bioavailability and also the magnitude of toxicity of Cr. The sorption of two environmentally important Cr species [Cr(III) and Cr(VI)] was examined using batch sorption, and the data were fitted to Langmuir and Freundlich adsorption isotherms. The effects of soil properties such as pH, CEC, organic matter (OM), clay, water-extractable SO₄ ^2– and PO₄ ^3–, surface charge, and different iron (Fe) fractions of 12 different Australian representative soils on the sorption, and mobility of Cr(III) and Cr(VI) were examined. The amount of sorption as shown by K _f was higher for Cr(III) than Cr(VI) in all tested soils. Further, the amount of Cr(III) sorbed increased with an increase in pH, CEC, clay, and OM of soils. Conversely, the chemical properties of soil such as positive charge and Fe (crystalline) had a noticeable influence on the sorption of Cr(VI). Desorption of Cr(VI) occurred rapidly and was greater than desorption of Cr(III) in soils. The mobility of Cr species as estimated by the retardation factor was higher for Cr(VI) than for Cr(III) in all tested soils. These results concurred with the results from leaching experiments which showed higher leaching of Cr(VI) than Cr(III) in both acidic and alkaline soils indicating the higher mobility of Cr(VI) in a wide range of soils. This study demonstrated that Cr(VI) is more mobile and will be bioavailable in soils regardless of soil properties and if not remediated may eventually pose a severe threat to biota.     

Influence of applied zinc and organic matter on zinc desorption kinetics in calcareous soils

Zinc (Zn) desorption from an exchange complex to solution, the release of Zn from organic matter (OM), crystalline minerals and other precipitates into the solution phase, is the process that controls Zn mobility in soils. An experiment was conducted to determine the pattern of Zn desorption and the soil characteristics affecting it. Desorption of Zn in 15 calcareous soils from southern Iran, treated with 10 mg Zn kg soil^?1 as zinc sulfate (ZnSO₄?7H₂O) and 10 g organic matter (OM) kg^?1 as feedlot cattle manure, equilibrated and extracted with diethylenetriamine pentaacetic acid (DTPA), was studied. Eight kinetic models were evaluated to describe the rate of Zn desorption of soil extracted with DTPA. There was a rapid rate of desorption during the first 4 h followed by a slower rate during the next 12 h. Two-constant rate and simple Elovich models were determined as the best models describing Zn desorption kinetics. Zinc desorption increased as Zn was applied, whereas it decreased with applied OM. The constants of the simple Elovich (β_s) and two-constant rate equations (a and b) were closely correlated with cation-exchange capacity (CEC), OM and pH, which affect Zn solubility, sorption–desorption and diffusion in soils.     

土壤中黑碳对农药敌草隆的吸附-解吸迟滞行为研究

采用批处理振荡法和连续稀释法分别测定了敌草隆在人工添加黑碳土壤和自然形成的不同有机质和黑碳含量的土壤中的吸附一解吸行为。吸附结果表明，人工添加黑碳的土壤对敌草隆的吸附强度和吸附容量以及吸附等温线的非线性均随土壤黑碳添加浓度的增加而逐步增大；自然土壤的吸附容量和吸附强度随土壤总有机质含量增加而增加，但吸附等温线的非线性则与土壤中黑碳对有机质的相对含量有关，黑碳比例越高，等温线非线性越大。解吸实验结果表明，无论是人工添加黑碳的土壤还是自然土壤，对敌草隆的解吸迟滞作用均随土壤黑碳含量增高而愈明显。     

甲硫嘧磺隆在土壤中的吸附和解吸特性研究

Methiopyrsulfuron is a new low-rate sulfonylurea herbicide for weed control in wheat; however, there is a lack of published information on its behavior in soils. In this study, methiopyrsulfuron adsorption and desorption were measured in seven soils sampled from Heilongjiang, Shandong, Jiangxi, Sichuan, Anhui, and Chongqing provinces of China using a batch equilibrium method. The Freundlich equation was used to described its adsorption and desorption. Adsorption isotherms were nonlinear with the values of Kf-ads, the Freundlich empirical constant indicative of the adsorption capacity, ranging from 0.75 to 2.46, suggesting that little of this herbicide was adsorbed by any of the seven soils. Soil pH and organic matter content (OM) were the main factors influencing adsorption; adsorption was negatively correlated with pH and positively correlated with OM. Methiopyrsulfuron desorption was hysteretic on the soils with high OM content and low pH.     

磷肥和有机肥对不同磷水平土壤磷吸附-解吸的影响

采用培养试验结合Langmuir吸附等温方程进行拟合求出吸附、解吸的相关参数的方法,研究了磷肥和有机肥对不同磷水平土壤磷吸附和解吸特性的影响。结果表明,随土壤磷水平和磷肥和有机肥用量的增加,土壤最大吸磷量、土壤磷最大缓冲能力显著降低;土壤易解吸磷和土壤磷的解吸率显著增加。土壤易解吸磷和土壤磷的解吸率与土壤Olsen-P呈显著正相关;土壤最大吸磷量、土壤磷最大缓冲容量与土壤Olsen-P呈显著负相关。单位量磷肥所增加的土壤易解吸磷随着磷肥用量和土壤磷水平的增加而增大;土壤磷水平和磷用量是影响土壤磷最大吸磷量和土壤磷最大缓冲能力的重要因素。     

Zinc sorption–desorption by two Andepts: effect of pH and support medium

Laboratory experiments were carried out to evaluate the effect of pH, ionic strength and electrolyte composition on zinc sorption–desorption by two Andepts from the Canary Islands (Spain). At the natural soil pH, the soils exhibited little net negative surface charge and small Zn sorption capacities. More than 75% of the sorbed Zn was apparently strongly bonded. The pH greatly influenced the sorption–desorption reactions. Sorption increased with increasing pH, and retention increased abruptly at pH > 6.0. Sorption also occurred at pH values below the point of zero charge (PZC) of the soils, when most of the surface sites are positively charged. Desorption decreased continuously with rising pH and became a trace at pH > 6.0. An increase in the ionic strength of the background electrolyte decreased Zn sorption and enhanced the amount of sorbed metal that could be subsequently released. In the two soils, Zn sorption diminished somewhat in the K and Ca electrolytes as compared with the Na electrolyte. However, this did not happen at small Zn loadings. Desorption was not affected by the type of electrolyte and cation used. The results are consistent with chemisorption being responsible for most of the sorption. The results also suggested a strong affinity sorption or even precipitation at high pHs.     

Predicting and modelling availability of fluoride in soil from sorption properties

Usage of alkaline and saline groundwater with elevated concentrations of fluoride (F⁻) for irrigation of pastures requires an assessment of the mobility of F⁻ within the plant-water-soil continuum. Factors influencing F⁻ sorption and desorption in 95 Australian soils were examined. Pronounced differences in F⁻ sorption were observed across the soils, but these differences could not be explained by differences in soil pH, electrical conductivity or organic carbon. Rather, sorption was correlated with the content of Fe/Al hydrous oxides and kaolinite in soil. Sorption of F⁻ onto soils increased the solution pH and the ratio of (F⁻ adsorbed) to (OH⁻ desorbed) was consistently below 1, thereby indicating that adsorption of F⁻ results in the release of water and hydroxyl groups from, or co-adsorption of protons to, the sorbent surface. Maximum sorption occurred at pH values of approximately 5–6, whilst sulphate slightly increased (<5%) F⁻ sorption. Desorption was slightly decreased (~3%–7%) in presence of sulphate anions. Hence, it is unlikely that irrigation of soil with alkaline and saline groundwater, in combination with soil applications of gypsum and sulphur to limit pH fluctuations, would increase mobility of F⁻ in soil. Finally, the irrigation of soil columns with 1200–1500 mm of alkaline and saline groundwater containing 0.18 mM F⁻, as would commonly occur in irrigation systems using coal seam gas associated water in Australia, resulted in a F⁻ concentration of 0.05 mM at 10 cm depth and the measured values were in excellent agreement with modelled F⁻ movement based on sorption parameters. Thus, sorption parameters can be used to identify soils which minimize movement of F⁻ because of their strong F⁻ sorption. Based on these results, safe limits for irrigation of soil can be established which avoid F⁻ toxicity risks to plants, animals and contamination of water resources.     

Sorption and mobility of 14C-labeled imazaquin and metolachlor in four soils as influenced by soil properties

Aqueous batch-type sorption-desorption studies and soil column leaching studies were conducted to determine the influence of soil properties, soil and suspension pH, and ionic concentration on the retention, release, and mobility of [14C]imazaquin in Cape Fear sandy clay loam, Norfolk loamy sand, Rion sandy loam, and Webster clay loam. Sorption of [14C]metolachlor was also included as a reference standard. L-type sorption isotherms, which were well described by the Freundlich equation, were observed for both compounds on all soils. Metolachlor was sorbed to soils in amounts 2-8 times that of imazaquin, and retention of both herbicides was related to soil organic matter (OM) and humic matter (HM) contents and to herbicide concentration. Metolachlor retention was also related to soil clay content. Imazaquin sorption to one soil (Cape Fear) increased as concentration increased and as suspension pH decreased, with maximum sorption occurring in the vicinity of pK(a1) = (1.8). At pH levels below pK(a1) imazaquin sorption decreased as hydronium ions (H3O+) increased and competed for sites. NaCl was more effective than water in desorption of imazaquin at pH levels near the pK(a1). Mechanisms of bonding are postulated and discussed. The mobility of imazaquin through soil columns was in the order Rion > or = Norfolk > Cape Fear > or = Webster, whereas for metolachlor it was Rion > or = Norfolk > Webster > or = Cape Fear. Imazaquin was from 2 to 10 times as mobile as metolachlor.     

Sorption and desorption of diuron and norflurazon in Florida citrus soils

The potential for surface and groundwater contamination of soil applied herbicides is partly dependent on soil properties. Sorption and desorption of diuron and norflurazon were studied in seven soils representative of the southern citrus-belt of Florida using the batch-equilibrium technique. Sorption of herbicides was influenced by soil properties. Sorption coefficients (K _d) ranged from 0.84 to 3.26 mL g^?1 for diuron and 0.63 to 2.20 mL g^?1 for norflurazon indicating weak to moderate binding of herbicides to soil. For norflurazon, K _dwas significantly related to organic C content, soil pH, and cation exchange capacity. For diuron, absence of a significant relationship between K _dand selected soil properties suggests that the soil properties other than those studied may play a role in determining sorption on these soils. Desorption studies showed that higher amounts of diuron and norflurazon was desorbed by water than by 0.5 M CaCl₂. An inverse relationship was apparent between herbicides sorbed and that which was desorbed among the soils studied. The soil which exhibited higher sorption had lower desorption and the soil which exhibited lower sorption had higher desorption.     

Soil pH Change and Crop Responses with Long-Term Liming Applications in Tilled and Untilled Systems

An 8-year field study measured soil pH changes annually at various depth increments. Limestone was applied to tilled and untilled field strips annually for 8 years at either a 2.0 Mg/ha rate (100% calcium carbonate efficiency) and once every 4 years at the 8.0 Mg/ha rate (100% calcium carbonate efficiency), or as a water-treatment-plant limestone by-product in two replicated field trials. Liming materials increased soil pH in the 0- to 5-cm and 5- to 10-cm depths with time in untilled soils. Incorporated liming materials increased soil pH faster at the 5- to 10-cm depth and increased soil pH at the 10- to 15-cm depth. Mean maize and soybean grain yields increased for all liming materials, and maize ear leaf P and soybean shoot P and Ca increased after liming at the last year of the study. Consistent surface applications of liming materials without incorporation can mitigate acidification and improve crop yields in highly buffered soils.     

Azimsulfuron sorption--desorption on soil

The sorption and desorption of the herbicide azimsulfuron, N-[[(4-dimethoxypyrimidin-2-yl)amino]carbonyl]1-methyl-4-(2-methyl-2H-tetrazole-5-yl)1H-pyrazole-5-sulfonamide, were studied using five soils. Sorption isotherms conformed to the Freundlich equation. It was found that pH is the main factor influencing the sorption and that the sorption on soils was negatively correlated with pH. The highest level of sorption was measured on soils with low pH and high organic carbon content. Moreover, inorganic soil colloids, for example, smectite clay minerals and iron oxides, contributed to the sorption of azimsulfuron. Desorption was hysteretic on soils with high organic and inorganic colloid contents.     

萘和p,p′-DDE在典型包气带介质上的吸附动力学及吸附-解吸特征

选取3种典型包气带土壤为吸附剂,萘和p,p′-DDE为吸附质,研究了其吸附动力学特征及吸附解吸规律。实验结果显示,初始浓度越大,吸附到达平衡所需时间就越短。数据拟合结果表明,单一级次的动力学方程难以描述两种吸附质的吸附动力学特征,分析认为土壤对有机污染物的吸附过程不是单一反应,而是有机污染物在无机矿物、无定型有机碳和凝聚型有机碳上同时进行吸附反应的复合结果。萘与p,p′-DDE的吸附、解吸过程均表现出非线性,Freundlich方程的吸附指数n在不同程度上偏离1;两种污染物在土样中的吸附过程不完全可逆,Kow、初始浓度以及土壤有机碳含量（fo）c的差异都影响其在土壤不同组分上的吸附百分比,进而影响解吸率。萘更多地吸附在无机矿物表面及无定型有机碳上,随着初始浓度的增大（37.7~780.9μg.L-1）,解吸率可从10%左右增至近85%;而当初始浓度为37.7μg.L-1时,随foc的增大（0.01%~0.65%）,解吸率由12.39%降至3.90%。p,p′-DDE则更多地吸附在凝聚型有机碳上,解吸率随浓度的变化（11.0~275.1μg.L-1）仅在1%~5%内波动,当初始浓度为11.0μg.L-1时,解吸率随foc的增大由4.49%降至1.06%。两者解吸率都和foc呈负相关关系。     

Sorption of Cd and Pb by selected temperate and semi-arid soils: effects of sludge application and ageing of sludged soils

Five soils from semi-arid regions of India and 5 soils from England were compared with regard to their ability to sorb Cd and Pb when mixed with sewage sludge and as unsludged controls. The application of sewage sludge at 150t ha^?1 significantly increased the amount of Cd retained by the soils. The sorption data were statistically best-fit to the linearized Freundlich equation and the slopes of the isotherms were steeper with sludge application, indicating an increased affinity for Cd in the soil-sludge mixtures. A similar trend in Pb sorption was also observed for the English soils following the sludge treatment. In contrast, most of the Indian soils showed a decline in Pb sorption following the sludge application. Liming an acidic English soil to pH 7.0 was shown to increase its metal sorption capacity. The longer-term persistence of these observed effects of sewage sludge addition on metal sorption by soils was investigated in two sludge-soil mixtures maintained under experimental conditions for up to 450 days. Samples of these soils taken 1,60 and 450 days after the mixing with the sludge were batch equilibrated with Cd and Pb and it was found that the metal retention in both soils decreased significantly over this time period.     

长期不同施肥红壤磷素特征和流失风险研究

为探索长期施肥对红壤磷素吸附固持的影响,分析不同施肥土壤磷流失风险及影响因素。在南方丘陵区红壤上开展了持续25年的长期定位试验,处理包括:不施肥(CK)、施氮肥(N)、施磷肥(P)、施钾肥(K)、施氮磷钾肥(NPK1)、施2倍量氮磷钾肥(NPK2)、单施有机肥(OM)和氮磷钾配施有机肥(MNPK)。研究了不同施肥下土壤全磷、Olsen-P、Mehlich1-P、CaCl2-P含量及磷吸持指数(PSI)、磷饱和度(DPS)的变化,探讨不同施肥处理土壤对磷的吸附和解吸特征,并分析了土壤磷指标与土壤有机碳、pH、CEC之间的关系。结果表明:长期施用化学磷肥有利于补充土壤磷素,特别是土壤全磷,并使Olesn-P和Mehlich 1-P有增加趋势,而对CaCl2-P影响不显著;施用化肥对DPS影响不显著,单施磷会降低PSI,低量氮磷钾提高了PSI,高量氮磷钾处理与对照差异不显著;长期施用有机肥(猪粪)土壤全磷增加,而Olsen-P、Mehlich 1-P和CaCl2-P则大幅累积, PSI显著降低, DPS显著增加。长期施用化肥处理土壤对新添加磷的吸附较强,长期施用有机肥降低了土壤对新添加磷的吸附;土壤全磷、Olsen-P、Mehlich1-P、CaCl2-P、PSI、DPS及最大吸附容量(Qm)与土壤pH、CEC、土壤总有机碳(TSOC)、土壤水溶性有机碳[冷水提取水溶性有机碳(CWSOC)和热水提取水溶性有机碳(HWSOC)]间相关性较高;土壤磷指标和土壤有机碳、pH、CEC指标之间存在典型相关关系,第1对和第2对典型变量的典型相关系数分别为0.997和0.951,达显著水平。研究表明,施用有机肥是调节土壤磷的供给和保持的重要措施,土壤水溶性有机碳和pH可能是反映红壤磷素供应和流失的关键指标。     

Nitrogen mineralization and nitrifier activity in limed and urea‐treated soils

Abstract

The effect of liming on mineralization and soil nitrifier activity (NA) was investigated with Brookston clay (pH 5.7) and Haldimand clay (pH 4.7). Liming increased the rate of mineralization in both soils but at a rate about 4‐times greater in Haldimand clay than Brookston clay. A significant increase in N mineralization due to liming occurred in both soils only when pH was raised above 6.0. The rate of mineralization was greater than nitrification in the Haldimand soil resulting in NH₄ ⁺ accumulation. Nitrifier activity increased with liming of Brookston clay, but decreased in Haldimand clay after 15 days of incubation. There was a significant increase in nitrifier activity due to liming from 15 to 60 days in Haldimand clay. After 60 days nitrifier activity in limed treatments increased by five times over the unlimed control.

The nitrification of urea powder (1000 mg N.kg^‐1) mixed into the soil was also studied in several soils incubated at 15°C for 28 days. There was evidence up to 14 days that nitrification of urea was correlated with initial nitrifier activity. Between 14 and 28 days, other factors such as soil pH and possible ammonia toxicity in coarser textured soils as well as nitrifier activity were important. Accumulation of nitrite occurred mainly in soils with a pH above 7.0 up to 28 days especially where nitrifier population enrichment was not done.     

土壤组分对广东省酸性水稻土磷吸附参数的影响

Soil components affecting phosphate sorption parameters were studied using acid paddy soils derived from basalt, granite, sand-shale and the Pearl River Delta sediments, respectively, in Guangdong Province.For each soil, seven 2.50 g subsamples were equilibrated with 50 mL 0.02 mol L-1 (pH=7.0) of KCl containing 0, 5, 10, 15, 25, 50 and 100 ng P kg-1, respectively, in order to derive P sorption parameters (P sorption maximum, P sorption intensity factor and maximum buffer capacity) by Langmuir isotherm equation. It was shown that the main soil components influencing phosphate sorption maximum (Xm) included soil clay, pH,amorphous iron oxide (Feo) and amorphous aluminum oxide (Alo), with their effects in the order of Alo ＞Feo ＞ pH ＞ clay. Among these components, pH had a negative effect, and the others had a positive effect.Organic matter (OM) was the only soil component influencing P sorption intensity factor (K). The main components influencing maximum phosphate buffer capacity (MBC) consisted of soil clay, OM, pH, Feo and Alo, with their effects in the order of Alo ＞ OM ＞ pH ＞ Feo ＞ clay. Path analysis indicated that among the components with positive effects on maximum phosphate buffer capacity (MBC), the effect was in the order of Alo ＞ Feo ＞ Clay, while among the components with negative effects, OM ＞ pH. OM played an important role in mobilizing phosphate in acid paddy soils mainly through decreasing the sorption intensity of phosphate by soil particles.     

Effects of heating and autoclaving on sorption and desorption of phosphorus in some forest soils

A number of biological and chemical processes may affect soil phosphorus availability when forest fires occur, partly as a result of heating. We describe here a laboratory experiment to study the effects of soil heating on changes in sorption and desorption of P. Autoclaving was also included as an additional treatment of moist heating under pressure. Five forest soils (two Podzols, one Arenosol, one Luvisol and one Alisol) were heated to 60°C, 120°C and 250°C or autoclaved for 30 min. They were repeatedly extracted with Bray I and analysed for inorganic and organic P fractions. The desorbed P data were fitted to an asymptotic exponential equation to obtain the desorption rate and capacity parameters. Podzol and Arenosol soils showed a quick P desorption after heating, while Luvisol and Alisol soils showed a slow desorption rate. The immediate increase in available P that occurred after heating or autoclaving originated mostly from solubilisation of microbial metabolites and soil organic components. Autoclaving decreased P sorption capacity in all soils, but the effects of heating on P sorption differed among soils. Except for one of the soils, the low P-fixing soils (Podzol and Arenosol) showed a decrease in P sorption when heated to high temperatures, whereas the high P-fixing soils (Luvisol and Alisol) showed little changes after heating. Fire intensity and soil characteristics are important factors determining short-term and long-term soil P dynamics.