Comparison of different models for phosphate sorption as a function of the iron and aluminium oxides of soils

Phosphate sorption on topsoil and subsoil samples from different soils located in the eastern part of Germany was studied. Two models were fitted to sorption data obtained after 4 and 40 d of gentle shaking. The models differ with respect to the fractions of iron and aluminium (hydr)oxides that are considered and whether the phosphate initially sorbed in the soil is taken into zccount. Oxalate-extractable P, (P_ox), appears to be a major part of the total soil P. The total P sorption measured, F, was predominantly related to the amounts of amorphous iron (Fe_ox) and aluminium (Al_ox). A significant relation between crystalline iron (Fe_d– Fe_ox) and total P sorption was not found. Reversibly adsorbed phosphate (P_i), measured after 40 d reaction time, was a function of clay content and content of amorphous iron and aluminium (hydr)oxides.     

Estimation of the phosphorus sorption capacity of acidic soils in Ireland

The test for the degree of phosphorus (P) saturation (DPS) of soils is used in northwest Europe to estimate the potential of P loss from soil to water. It expresses the historic sorption of P by soil as a percentage of the soil's P sorption capacity (PSC), which is taken to be α (Al_ox + Fe_ox), where Al_ox and Fe_ox are the amounts of aluminium and iron extracted by a single extraction of oxalate. All quantities are measured as mmol kg soil^?1, and a value of 0.5 is commonly used for the scaling factor α in this equation. Historic or previously sorbed P is taken to be the quantity of P extracted by oxalate (P_ox) so that DPS = P_ox/PSC. The relation between PSC and Al_ox, Fe_ox and P_ox was determined for 37 soil samples from Northern Ireland with relatively large clay and organic matter contents. Sorption of P, measured over 252 days, was strongly correlated with the amounts of Al_ox and Fe_ox extracted, but there was also a negative correlation with P_ox. When PSC was calculated as the sum of the measured sorption after 252 days and P_ox, the multiple regression of PSC on Al_ox and Fe_ox gave the equation PSC = 36.6 + 0.61 Al_ox+ 0.31 Fe_ox with a coefficient of determination (R²) of 0.92. The regression intercept of 36.6 was significantly greater than zero. The 95% confidence limits for the regression coefficients of Al_ox and Fe_ox did not overlap, indicating a significantly larger regression coefficient of P sorption on Al_ox than on Fe_ox. When loss on ignition was employed as an additional variable in the multiple regression of PSC on Al_ox and Fe_ox, it was positively correlated with PSC. Although the regression coefficient for loss on ignition was statistically significant (P < 0.001), the impact of this variable was small as its inclusion in the multiple regression increased R² by only 0.028. Values of P sorption measured over 252 days were on average 2.75 (range 2.0–3.8) times greater than an overnight index of P sorption. Measures of DPS were less well correlated with water‐soluble P than either the Olsen or Morgan tests for P in soil.     

Phosphorus buffering capacity of substrate clays and its significance for plant cultivation

Peat is commonly used as the main component of horticultural substrates, but it has a very low buffering capacity for the anionic macronutrient phosphorus (P), which can be increased by the addition of clays. The aim of this study was to characterize the P adsorption capacity of different substrate clays and to evaluate its significance for plant P uptake. Substrate clays were characterized with a single‐point batch experiment and adsorption and desorption isotherms. The data were fitted to the Langmuir equation for a calculation of the maximum adsorption capacity. Additionally, the contents of oxalate extractable Fe and Al (ΣFe_ox + Al_ox) were determined. The influence of a varying P adsorption capacity of the clays on the P availability to plants in the respective peat–clay substrates and pure peat was investigated in a growth experiment with Impatiens walleriana fertigated with 0, 17, and 35 mg P L^?1 solution, respectively. The observed and calculated (Langmuir) P adsorption capacity of the clays could be well‐characterized by both the batch experiment and the adsorption isotherms and was highly correlated with the ΣFe_ox+Al_ox. A higher P adsorption capacity of the clay amendment in mixed substrates resulted in a lower P concentration in the substrate solution, while the CAT extractable P concentration (P_CAT) was the same. Plant growth and shoot P concentrations were enhanced in the substrates, showing a higher P adsorption capacity, since plants were able to take up the whole amount of P_CAT, and also part of the non‐CAT extractable P. However, the release rate was too low to ensure optimal plant growth, which was in accordance with the result of the desorption experiment. The absolute extent of P release was increased with the increasing P adsorption capacity of the clays and higher degree of P saturation (DPS).     

Predicting the degree of phosphorus saturation using the ammonium acetate–EDTA soil test

As a result of the important role played by phosphorus (P) in surface water eutrophication, the susceptibility of soils to release P requires evaluation. The degree of phosphorus saturation, assessed by oxalate extraction (DPS_ox), has been used as an indicator. However, most laboratories do not include DPS_ox in routine soil tests because of cost and time. This study evaluates the suitability of the ammonium acetate extraction in the presence of EDTA (AAEDTA), the standard soil test P (STP) in Wallonia (Southern Belgium), to predict DPS_ox; we also compared it with the Mehlich 3 extraction. Ninety‐three topsoil samples were collected in agricultural soils throughout Wallonia. Good correlations were found between the AAEDTA and the Mehlich 3 methods for P, Fe and Al (r = 0.85, 0.77 and 0.86, respectively). An exponential relationship was found between P_AAEDTA and DPS_ox. Results of principal component analysis and regression demonstrated that STP can be used to predict DPS_ox (r = 0.93) after logarithmic transformation. Soil test Al was also a good indicator of the P sorption capacity (PSC_ox) of soils (r = 0.86). Including the clay fraction in regression equations only slightly improved the prediction of PSC_ox (r = 0.90), while other readily available data (such as pH or organic carbon) did not significantly improve either DPS_ox or PSC_ox predictions.     

The effect of soil flooding on the transformation of Fe oxides and the adsorption/desorption behavior of phosphate

As repeatedly reported, soil flooding improves the availability of P to rice. This is in contrast with an increased P sorption in paddy soils. The effects of soil flooding on the transformation of Fe oxides and the adsorption/desorption of P of two paddy soils of Zhejiang Province in Southeast‐China were studied in anaerobic incubation experiments (submerging with water in N₂ atmosphere). Soil flooding significantly increased oxalate‐extractable Fe (Fe_ox), mainly at the expense of dithionite‐soluble Fe (Fe_DCB), as well as oxalate‐extractable P (P_ox), but decreased the ratio of P_ox/Fe_ox. Flooding largely increased both, P adsorption and the maximum P adsorption capacity. The majority of newly sorbed P in the soils was P_ox, but also more newly retained P was found to be not extractable by oxalate. Flooding also changed the characteristics of P desorption in the soils. Due to a decrease of the saturation index of the P sorption capacity, P adsorbed by flooded soils was much less desorbable than that from non‐flooded soils. There are obviously significant differences in the nature of both, the Fe_ox and P_ox fractions under non‐flooded and flooded conditions. The degree of the changes in Fe_ox, P_ox, P adsorption and P desorption by flooding depended on the contents of amorphous and total Fe oxides in non‐flooded soils. Our results confirm that the adsorption and desorption behavior of P in paddy soils is largely controlled by the transformation of the Fe oxides. The reasons of the often‐reported improved P availability to rice induced by flooding, in spite of the unfavorable effect on P desorbability, are discussed.     

Assessing alternative approaches to predicting soil phosphorus sorption

Twenty‐five pasture soils were sampled from high‐rainfall zones of southeastern Australia to examine relationships between soil properties, and between soil properties and P buffering capacity (PBC) measures. Correlations between PBC values and soil properties were generally poor, with the exception of oxalate‐extractable Al (Al_ox) (r ≥ 0.97). Predictions of PBC were further improved when clay, as well as Al_ox, was included in a linear regression model (r² ≥ 0.98). When Al_ox and oxalate‐extractable Fe were excluded from the modelling exercise, a more complex three‐term linear regression model, including pH_H2O, exchangeable H and cation exchange capacity, adequately fitted both PBC values of the 25 soils examined in this study (r² ≥ 0.76). However, the Al_ox, Al_ox plus clay and the three‐term models gave poor predictions of the PBC values when the models were validated using 28 independent soils. These results emphasize the importance of model validation, because predictive models based on soil properties were not robust when tested across a broader range of soil types. In comparison, direct measures of PBC, such as single‐point P sorption measures, are more practical and robust methods of estimating PBC for Australian soils.     

Phosphorus exchange properties of European soils and sediments derived from them

The sorption and desorption of phosphorus (P) from eroding soil particles in land runoff are important processes contributing to agriculturally‐driven eutrophication. We investigated the P‐exchange properties and related chemical characteristics of contrasting European agricultural soils and sediment material eroded from them under indoor (small‐scale) and outdoor (larger‐scale) rainfall simulations. Quantity‐intensity (Q/I) relationships revealed large variation in equilibrium P concentrations at zero net P sorption (EPC₀) (0–10.3 mg l⁻¹) and instantly labile P (−Q₀, the amount of P to be desorbed to obtain a P equilibrium concentration of 0 mg l⁻¹) (2–75 mg kg⁻¹), both correlating closely with Al‐bound P and the P saturation degree of Al oxides (DPS_Alox). Maximum P sorption (Q_max) (43–515 mg kg⁻¹) also correlated most closely with Al_ox. The indoor and outdoor rainfall simulations produced sediments with different P sorption properties: in the indoor simulation (less kinetic energy, constant slope), the sediments had larger EPC₀ values, and usually larger −Q₀ values, than the sediments in the outdoor simulation (greater kinetic energy, variable slopes). Furthermore, the P exchange properties of the sediments differed from those of the bulk soil depending on the enrichment of soil P‐sorption components (Fe/Al oxides, clay). The outdoor simulation indicated that sites with gentle slopes produced sediments that were more enriched with Al_ox, Fe_ox, Mn_ox and organic C than those with steeper slopes. In this study, when the bulk soil had an initial EPC₀ greater than 1.3 mg l⁻¹, the outdoor rainfall simulation produced sediment with smaller EPC₀ and vice versa, indicating that, depending on the P status of the bulk soil, the sediment material was acting as source or sink for P during transport. However, on the basis of their EPC₀ values, most eroding sediments might be expected to desorb, rather than adsorb, P when entering surface water.     

Effect of iron oxide on phosphate sorption by calcite and calcareous soils

Pure calcite (AR grade CaCO₃) was treated with ferrous perchlorate solution to give a surface coating of iron (Fe) oxide. Maximum sorption (x_m) of phosphate (P) by the calcite increased from 18.2 to 160 mg P kg^?1 as the amount of coating increased from 0.00 to 16.0 g Fe₂O₃, kg^?1 CaCO₃. Evidence for Fe oxide coatings on carbonate minerals in two Sudanese soils was obtained by optical microscopy and electron-probe microanalysis. The relative contributions of carbonate and Fe oxide minerals, and Fe oxide coatings to P sorption in these soils were calculated, based on an assumed model of oxide distribution. Separate-phase Fe oxide was the major contributor (30–40%) to P sorption in the soils; the Fe oxide coatings on carbonate minerals were only minor contributors (< 6%), and the contribution of uncoated carbonate minerals was found to be negligible (<1 %). These results suggest a very minor role for carbonate minerals, even when coated with Fe oxide, in the sorption of P by these calcareous, Sudanese soils.     

上海土壤磷的吸附特性及缓冲性能的研究

本文以上海土壤为对象,研究选定了土壤磷等温吸附试验条件为:水土比10,平衡时间6天,控温25℃,磷加入量为100,200,400,600μgP/g土,溶液基质为0.01M CaCl₂。磷缓冲能力试验条件为:平衡时间2天,磷加入量为20,40,100,200μgP/g土。根据Freundlich, Tempkin和Langmuir方程计算的土壤吸附指标与土壤类型及土壤性质有密切关系,是土壤磷素肥力的重要指标。反映土壤缓冲能力的“磷肥指标”与土壤有机质、粘粒、活性铝及pH值相关较好。上海几种主要土壤中以青紫泥的最大吸附量(X_m),0.2ppm P吸附量和“磷肥指标”为最高,其次为青黄土,沟干泥和黄泥头,最小为夹沙泥。应用磷吸附指标与“磷肥指标”来预测土壤需磷量,初步试验是可行的,但实际应用还需进一步试验研究。     

Effects of Hydrilla Verticillata on Phosphorus Retention and Release in Sediments

Submerged macrophytes are commonly used for the environmental engineering of the controlling of shallow lake eutrophication, and are also an effective and valid alternative for the remediation of eutrophic water bodies, not only under experimental conditions but also under natural conditions. Therefore, the effects of submerged macrophytes on the improvement of shallow lake water quality have been intensively investigated. But the mechanism was not well understood, especially the mechanism of the effects of submerged macrophytes on the exchange of nutrients at sediment–water interface in shallow lakes. This study selected a familiar submerged macrophyte Hydrilla verticillata in China and evaluated the effects of H. verticillata on the phosphate retention and release at the lake sediment–water interface in a simulated condition. The effects of H. verticillata on the phosphate sorption isotherm, phosphorus (P) availability were investigated and the subsequent kinetics of P release was also measured by repeated extraction with CaCl₂ solution. Exchangeable Ca and ammonium oxalate-extractable Fe (Fe_ox) and Al (Al_ox) of the sediments were also determined. The results show that the contents of organic matter, cationic exchange capacity (CEC), Ca, Fe, Al, exchangeable Ca, Fe_ox and Al_ox of the sediments with H. verticillata were higher than those of the control sediments, and the contents of total phosphorus (TP), Olsen-P and reactive dissolve phosphorus (RDP) were lower. The sediments with H. verticillata had stronger P sorption ability and weaker ability of P release. H. verticillata did not significantly affect the trends of the sorption isotherms and kinetics of the released P on the sediments. H. verticillata can significantly increase the ability of P sorption, decrease in the ability of P desorption on sediments was one of the mechanism that maintained lower P levels of the overlying water through affecting the contents of organic matter, CEC, Ca, Fe, Al, exchangeable Ca, Fe_ox and Al_ox in sediments.     

Assessment of co‐blending water treatment residual with dairy manure to reduce phosphorus concentrations in run‐off in Northern Ireland

Losses of phosphorus (P) to water that follow manure applications can be high while water treatment residuals (WTR) have an appreciable capacity to sorb soluble P which is an important risk factor in determining the susceptibility of manure P to run‐off losses. The objective of this study was to assess whether co‐blending WTR with dairy cow manure prior to surface application would reduce P concentrations in run‐off from grassland. An alum‐derived WTR was collected from a water treatment works (WTW), dried and characterized for its phosphorus sorption capacity (PSC) based on oxalate‐extractable Al and Fe. Multipoint P sorption isotherms were used to calculate the Langmuir P sorption maximum (P_max) and equilibrium P concentration (EPC₀). The WTR contained 170 g Al_ox/kg and 2.2 g Fe_ox/kg with a nominal long‐term PSC of 118 g/kg. Following a 6 day incubation of WTR, the Langmuir P_max was 82.6 g/kg and the EPC₀ of 0.13 mg P/L. Laboratory incubations of manure co‐blended with WTR indicated that 144 g WTR/kg dry matter (DM) manure significantly lowered (P < 0.001) manure WSP by 71.5 ± 16.6% after 108 h, but lower WTR mixing rates of 72 and 36 g WTR/kg had no statistical effect on manure WSP. Results from a field experiment using simulated rain on 0.5‐m² grassland plots showed no significant effect on run‐off P 2 days after applying 50 m³/ha of 6% DM manure co‐blended WTR at rates of 150 and 250 g WTR/kg.     

Phosphorus Adsorption Isotherm: A Key Aspect for Effective Use and Environmentally Friendly Management of Phosphorus Fertilizers in Calcareous Soils

Crop response to the phosphorus (P) application is often erratic in most soil types in the world. In Algeria, there is no information on the P behavior in calcareous soils. The purposes of this work were to investigate the degree of P fixing capacity and to predict P fertilizer requirements of crops according to calcareous levels in the soil. Soil samples (at 0–30 cm depth) were collected and spiked with 0, 25 and 50% of lime (CaCO₃). Phosphate sorption curves were well fitted to the Freundlich equation. Results indicated that the calcareous level was predominantly controlled the P sorption indices [sorption capacity (a), and P sorption energy (n)] to affect the estimation of external d P requirement (EPR_0.2) and P fertilizer rates. The understanding of P sorption and desorption by soils and extrapolating the developed relationship between soil calcareous contents and P fertilizer rates would be quite promising and accurate approach for the economic and effective use of P fertilizers in calcareous soils of Algeria.     

Untersuchungen zur Charakterisierung des pflanzenverfügbaren Phosphats in Thüringer Carbonatböden

Investigations on the characterization of plant available phosphate in Thuringian calcareous soils Phosphate availability in Thuringian calcareous soils and its characterization by CAL‒, NaHCO₃-, H₂O- and CaCl₂-soil tests was investigated in laboratory and pot experiments. Soil CaCO₃ contents > 10% increase the pH value of CAL solution and thus decrease phosphate extractability. The increase of pH also causes an inadequate assessment of plant available phosphate by H₂O- and CaCl₂-soil tests. The CAL soluble P content of the soil corrected by the pH value of the extraction solution was most suitable for the forecast of P uptake of corn in a pot trial. From both parameters P availability indices for calcareous soils can be calculated which are comparable with those in soils containing < 5% CaCO₃. The equation, which still has to be verified in field experiments, reads as CAL-P_corrected = CAL-P_measured · (1 + 0.83·〈pH-value_{CAL solution} — 4.1〉).     

Effects of soil organic matter on pH-dependent phosphate sorption by soils

Effects of soil organic matter (80M) on P sorption of soils still remain to be clarified because contradictory results have been reported in the literature. In the present study, pH-dependent P sorption on an allophanic Andisol and an alluvial soil was compared with that on hydrogen peroxide (H₂0₂)-treated, acid-oxalate (OX)-treated, and dithionite-citrate- bicarbonate (DCB)-treated soils. Removal of 80M increased or decreased P sorption depending on the equilibrium pH values and soil types. In the H₂O₂ OX-, and DCB-treated soils, P sorption was pH-dependent, but this trend was not conspicuous in the untreated soils. It is likely that 80M affects P sorption of soils through three factors, competitive sorption, inhibition of polymerization and crystallization of metals such as AI and Fe, and flexible structure of metal-80M complexes. As a result, the number of available sites for P sorption would remain relatively constant in the wide range of equilibrium pH values in the presence of 80M. The P sorption characteristics were analyzed at constant equilibrium pH values (4.0 to 7.0) using the Langmuir equation as a local isotherm. The maximum number of available sites for P sorption (Q _max) was pH-dependent in the H₂0₂-, OX-, and DCBtreated soils, while this trend was not conspicuous in the untreated soils. Affinity constants related to binding strength (K) were less affected by the equilibrium pH values, soil types, and soil treatments, and were almost constant (log K ≈ 4.5). These findings support the hypothesis that 80M plays a role in keeping the number of available sites for P sorption relatively constant but does not affect the P sorption affinity. By estimating the Q _max and K values as a function of equilibrium pH values, pH-dependent P sorption was well simulated with four or two adjustable parameters. This empirical model could be useful and convenient for a rough estimation of the pH-dependent P sorption of soils.     

Phosphate sorption characteristics of major soils in Okinawa,Japan

Abstract

Phosphate sorption isotherms were determined for 16 representative major soils developed from different parent materials on Okinawa. Phosphate sorption characteristics were satisfactorily described by the Langmuir equation, which was used to determine phosphorus (P) sorption maxima of the soils. Phosphate sorption maxima ranged from 630 to 2208 mg P kg^‐1 soil (mean 1,362 mg P kg^‐1). The standard P requirement (i.e., the amount of P required to attain 0.2 mg P L^‐1 equilibrium solution) followed the same trend as sorption maximum (r =0.94***), with values ranging from 132 to 1,020 mg P kg^‐1 soil (mean 615 mg P kg^‐1). This mean value corresponds to fertilizer addition of 923 kg P ha^‐1 indicating that the soils have high P fertilizer requirements. Results of simple linear regression analysis indicated that sorption maximum was significantly correlated with clay content, organic matter, oxalate iron (Fe), pyrophosphate Fe, DCB aluminum (Al), oxalate Al, and pyrophosphate Al, but not with DCB Fe, pH, or available P content. The best regression model for predicting sorption maximum was the combination of clay, organic matter, pyrophosphate Fe, and DCB Al which altogether explained 79% of the variance in sorption maximum. The equation obtained could offer a rapid estimation of P sorption in Okinawan soils.     

High gradient magnetic separation of some soil clays from Nigeria, Brazil and Colombia.

High gradient magnetic separation was used to fractionate the clay from some tropical soils. Acid-oxalate-extractable iron (Fe_ox) and aluminium (Al_ox) and total carbon were measured in the whole clay, the magnetic fraction and the tailings. The magnetic separation resulted in a wider range of concentrations of these elements than in the whole clays. In each of the clays Fe_ox was greater in the magnetic fraction than in the tailings; Al_ox was more variable. Carbon was also concentrated in the magnetic fraction suggesting that it is associated more with Fe_ox than Al_ox. The relationships between Fe_ox, Al_ox and carbon depend on soil classification and soil age.     

THE HIGH- AND LOW-ENERGY PHOSPHATE ADSORBING SURFACES IN CALCAREOUS SOILS

The two-surface Langmuir equation was used to study P adsorption by 24 calcareous soils (pH 7.2-7.6; 0.8-24.2 per cent CaCO₃) from the Sherborne soil series, which are derived from Jurassic limestone. High-energy P adsorption capacities (x″_m) ranged from 140–345 μg P/g and were most closely correlated with dithionite-soluble Fe. Hydrous oxides therefore appear to provide the principal sites, even in calcareous soils, on which P is strongly adsorbed (x″_m 6–51 ml/μg P). The low-energy adsorption capacities (x″_m) ranged from 400–663 μg P/g and were correlated with organic matter contents and the total surface areas of CaCO₃ but not with per cent CaCO₃, pH, or dithionite-soluble Fe. Total surface areas of CaCO₃ in the soils ranged from 4.0 to 8.5 m²/g soil. Low-energy P adsorption capacities agree reasonably with values (100 pg P/m²) for the sorption of phosphate on Jurassic limestones but phosphate was bonded much less strongly by soil carbonates (k″= 0.08–0.45 ml/μg P) than by limestones (k～10.0 ml/μg P). Low-energy P adsorption in these soils is tentatively ascribed to adsorption on sites already occupied by organic anions (and probably also by bicarbonate and silicate ions) which lessen the bonding energy of co-adsorbed P.     

Phosphate sorption in relation to aluminum and iron oxides of oxisols from Ghana

Abstract

Phosphate (P) sorption characteristics of six natural Ghanaian Oxisols, selected because of their hydrological and topographical suitability for agriculture, were evaluated. Availability of P appears to be adequate for half of the soils as suggested by the Bray P1 test and determination of the standard P requirement (SPR), i.e., the amount of P sorbed at a concentration of 0.2 ppm P (6.46 μM). The SPR was found to be very closely related to P_max (Langmuir P sorption capacity), which in turn, was significantly correlated with oxalate‐extractable aluminum (Al) (Al_o) and iron (Fe) (Fe_o) and related (not significantly) to the difference between dithionite‐citrate‐bicarbonate‐extractable Fe (Fe_d) and oxalate‐extractable Fe. Accordingly, P_max is fairly well predicted by the model of Borggaard: P_ca]e=0.211#lbÀl_o+0.115#lbFe_o+ 0.05#lb(Fe_d‐Fe_o)+0.3, except for one soil strongly enriched in Fe oxides, mainly goethite. This goethite was found by X‐ray diffraction analysis to consist of crystals larger than normally found for pedogenic Fe oxides. The difference between P_max and P_calc for this soil could, therefore, be attributed to the occurrence of these large Fe oxide crystals, because P sorption will decrease with increasing crystal size (decreasing specific surface area).     

Potential Iron and Phosphate Mobilization During Flooding of Soil Material

This study shows that mobilization of phosphate from soils under anaerobic conditions can be intimately coupled with reductive dissolution of iron from iron oxides. Among four soil samples from the reclaimed Skjernå estuary in Denmark incubated anaerobically and amended with glucose, 28–39% of the dithionite-citrate-bicarbonate-extractable iron and 10–25% of the oxalate-extractable phosphorus (P_ox) were released to the soil solution after 31 days. Significant correlation (r = 0.992**) between the molar ratio P_ox/(Fe_ox + Al_ox) for the aerobic samples and (P_{P sol}/Fe_sol) (the molar ratio between phosphate and iron in solution during anaerobic incubation), indicates that the phosphate saturation status of the soil is an important determinant of the amount of phosphate released during flooding of moderately acid soils.     

Element uptake in thalli of the lichen Physcia caesia from sandstone and calcareous substratum

Physcia caesia is a foliose, saxicolous lichen commonly found on weakly acidic to alkaline rock and artificial calcareous substrata. Uptake of iron and phosphate, which are known to be significant for governing the calcifuge‐calcicole behavior of lichens (as well as vascular plants), was studied in individuals of P. caesia deriving either from variegated sandstone or concrete. Samples from either substratum originated from walls erected at the same location, i.e., lichens were exposed to the same atmospheric element load and microclimate prior to the experiments. Element uptake was investigated after short‐term incubation in the laboratory involving solutions of FeCl₂, FeCl₃, and KH₂PO₄ at pH 3 and 8. Uptake of Fe²⁺ was significantly higher at either pH in the thalli from concrete than in those from sandstone, whereas Fe³⁺ uptake was not significantly different between the two groups of lichen thalli, though there was an insignificant trend for higher Fe³⁺ uptake at pH 8 in the samples from concrete. Phosphate uptake also was more efficient in thalli deriving from concrete than in those from sandstone, even though the initial P content was higher in the samples from sandstone. The results suggest that the ability of P. caesia to adapt Fe and P uptake to the pH‐dependent availabilities of these nutrients is responsible for the potential of the species to grow both on weakly acidic and alkaline substrata.