Zinc Adsorption by Mineral Soils of Finland

Abstract

Zinc adsorption by 10 (pH 4.0–6.5) cultivated mineral soils from Finland was studied in batch experiments. Additions of Zn ranged up to 600 mg kg^?1 of soil and the corresponding equilibrium concentrations were 0.1–13 mg 1^?1. In each soil, Zn adsorption conformed to the Freundlich isotherm. Despite a relatively low initial Zn adsorption by the acidic soils, each of the soils proved to have a high potential to adsorb Zn, but the capacity was highly pH dependent. In addition to the conventional Freundlich adsorption isotherms, calculated separately for each soil, extended Freundlich-type isotherms that also incorporate soil pH and other soil characteristics were used to describe Zn adsorption of several soils simultaneously in one equation. The pH-dependent Freundlich adsorption isotherm proved to serve as a practical tool to assess Zn adsorption by soils varying in pH and other characteristics.     

Zinc Sorption Behavior in Soils with Divergent Characteristics

Adsorption studies are important to determine the retention and release of applied plant nutrients and the efficiency of fertilization. The present study was conducted to delineate the zinc (Zn) adsorption behavior of soils with varying characteristics. In this study, adsorption behavior of Zn was studied at varying Zn concentrations and temperatures in three different soils collected from the Research Farm of Indian Agricultural Research Institute (IARI), New Delhi (Inceptisols, Typic Haplustepts), soil (Inceptisols, Typic Ustocrept) from a farmer’s field in Shamgarh, Karnal, Harayana, and the Hayathnagar Research Farm of Central Research Institute For Dryland Agriculture (CRIDA), Hyderabad, (Haplustalf). The results of this study revealed that the adsorption of Zn as well as differential buffering capacity (DBC) was greater in Typic Haplustepts of IARI and Typic Ustocrept of Karnal than Haplustalf of CRIDA, Hyderabad. However, the supply power as well as percentage saturation (% sat.) was greater in Haplustalf of CRIDA, Hyderabad, than Typic Haplustepts of IARI and Typic Ustocrept of Karnal The results also revealed that irrespective of the soil types, Zn adsorption increased with an increase in Zn concentration and increase in temperature from 20 °C to 35 °C. When the adsorption data were fitted to isotherms, Langmuir and Freundlich isotherm fits were excellent, as evidenced by high r² (0.71 to 0.99) values. Thermodynamic parameters such as standard free energy (ΔG) were negative in both Typic Haplustepts and Typic Ustocrept soils, indicating spontaneous Zn adsorption reaction, but nonspontaneous reaction was observed in the case of Haplustalf soils.. Interestingly, both standard enthalpy (ΔH) and standard entropy (ΔS) were negative in all the three types of soils studies. The analogy and results of the present study would be useful in deciding the Zn fertilizer needs for a given soil type.     

Effect of Soil Properties on Boron Adsorption and Release in Arid and Semi-Arid Benchmark Soils

The adsorption isotherms indicated that the adsorption of boron (B) increased with its increasing concentration in the equilibrium solution. The Langmuir adsorption isotherm was curvilinear and it was significant when the curves were resolved into two linear parts. The maximum value of adsorption maxima (b1) was observed to be 7.968 mg B kg^?1 in Garhi baghi soil and the bonding energy (k) constant was maximum at 0.509 L mg^?1 in Jodhpur ramana soil. The Langmuir isotherm best explains the adsorption phenomenon at low concentrations of the adsorbent, which of course was different for different soils. There was significant correlation between b1 and clay (r = 0.905**), organic matter contents (r = 0.734*), and cation exchange capacity (CEC; r = 0.995**) of soils. A linear relationship was observed in all the soils at all concentration ranges between 0 and 100 mg B L^?1, indicating that boron adsorption data conform to the Freundlich equation. Soils that have a higher affinity for boron adsorption, like Garhi baghi, tended to desorb less amount of boron, that is, 43.54%, whereas Ballowal saunkhari desorbed 48.00%, Jodhpur ramana 48.42%, and Naura soil 58.88% of the adsorbed boron. Boron desorption by these soils is positively and significantly correlated with the sand content (r = 0.714**) and negatively with clay content (r = ?0.502*) and CEC (r = ?0.623**). The maximum value of 37.59 mg kg^?1 for desorption maxima (Dm) was observed in Garhi baghi soil and also a constant related to B mobility (Kd) was found to be maximum in Garhi baghi (0.222 L kg^?1) soil Note: *P<0.05; ^**P<0.01.     

Comparison of Five Adsorption Isotherms for Prediction of Zinc Retention in Calcareous Soils and the Relationship of their Coefficients with Soil Characteristics

Abstract

Zinc (Zn) deficiency is believed to be a consequence of reactions taking place between soluble Zn and the soil solid phase. This study was carried out to obtain quantitative relationships between Zn in equilibrium solution and that retained by the soil solids in calcareous soils. Twenty calcareous soils (saturated paste pH 6.9–7.9; calcium carbonate equivalent 4.64–22.80%) from Tehran province, Iran, were equilibrated with varying solution concentrations of Zn, and the amounts removed from the solution were used to check the fit to five adsorption isotherms, namely, Freundlich, Langmuir, Temkin, Gunary, and two‐surface Langmuir. Adsorption data of all soils showed statistically significant fit to the first four adsorption isotherms, but only 7 of the 20 soils tested showed fit to the two‐surface Langmuir. Coefficients of the adsorption isotherms showed statistically significant relationship with soil characteristics. Clay percentage, calcium carbonate equivalent percentage, and cation exchange capacity appeared to be the most influential soil characteristics with regard to Zn adsorption, whereas soil organic matter seemed to be of no importance under the conditions of this study.     

Comparison of Adsorption Isotherm Equations to Describe Boron Behavior in Soils Affected by Organic and Mineral Fertilization

The effects of different fertilization techniques—mineral [21% nitrogen (N)], organomineral (10% N), mycorrhiza inoculumns, wine-producing residues (three different formulas: distiller's residue, 2.2% N; anaerobic digestate, 2.8% N; and the same plus mycorrhizas inoculum), and compost by farm residues (2.0% N)—on adsorption of boron (B) were investigated. The soils, collected after a triennial lettuce (Lactuca sativa L. cv. ‘Bacio’) cultivation, were equilibrated using six B concentrations [0, 1, 5, 20, 50, and 100 mg B L^?1, as boric acid (H₃BO₃)]. The B adsorption was studied at two soil mass (m_s) to solution volume (v_s) ratios, m_s/v_s = 0.5 and 1, and the Langmuir, Eadie–Hofstee, Freundlich, and Temkin adsorption equations were fitted to the B adsorption data. The proportion of adsorbed B was gradually less in the more concentrated solutions, with differences in m_s/v_s ratio and in treatments: the percentage of B adsorbed was greater for m_s/v_s = 0.5 and for distiller's residue and mineral fertilizer. The Freundlich isotherm represented the measured B adsorption data well; at m_s/v_s = 0.5, the values of Freundlich adsorption maxima Xm varied from 93.14 to 111.88 mg kg^?1 (organomineral fertilizer and distiller's residue, respectively; at m_s/v_s = 0.5) and from 32.14 to 40.32 mg kg^?1 (mineral fertilizer and control, respectively; at m_s/v_s = 1). In our study, generally the B adsorption was greater with mineral fertilizers and distiller's residue, whereas the organomineral fertilizer led to a decrease in B adsorption. The parameters of adsorption isotherms were significantly correlated, at various degrees, with the exchangeable cation sodium. The adsorption isotherms were well explained by the lower soil mass to volume solution ratio in the order Freundlich > Temkin ≌ Langmuir > Headie–Hofstee.     

Boron adsorption and desorption in some acid soils of West Bengal,India

Laboratory and greenhouse experiments were conducted to determine the influence of soil properties on adsorption and desorption of boron (B) as well as to estimate the degree of reversibility of adsorption reactions. The utility of Freundlich and Langmuir equations for characterizing the plant availability of applied B in soils was established using soybean [Glycine max (L.) Merr.] as a test crop. The adsorption-desorption study revealed that Fe₂O₃ and clay were primarily responsible for retaining added B in all the 25 different soils under investigation. Organic carbon, pH and cation exchange capacity (CEC) positively influenced the adsorption of B while free Fe₂O₃, organic carbon and clay retarded release of B from these soils. The degree of irreversibility (hysteresis) of B adsorption/desorption increased with increase in organic carbon and CEC of these soils. Freundlich isotherm proved more effective in describing B adsorption in soils as compared to Langmuir equation. The split Langmuir isotherm demonstrated that any of the adsorption maxima, calculated from lower, upper or entire isotherm, could be of practical use. Contrary, bonding energy coefficient, calculated either at lower or higher equilibrium concentration failed to show any practical benefit. Regression models as a function of B application rate and adsorption equation parameters to predict B uptake from applied B, demonstrated the utility of Langmuir and Freundlich equation parameters.     

镉和铅在2种典型土壤中的吸附及其与温度的关系

采用批平衡法研究我国2种典型土壤对镉和铅的吸附特性及其与温度的关系,运用热力学参数△G°、△H°和△S°解释土壤镉和铅的吸附机理,并对镉和铅在复合共存情况下的吸附特性进行讨论.结果表明,镉和铅在土壤中的吸附过程表现出明显的非线性,镉和铅的吸附分别符合Freundlich模型和Lang-muir模型.壤土对镉和铅的最大吸附量和最大缓冲容量均大于红壤的.镉和铅复合共存时,2种重金属的吸附均受到抑制;温度升高时,镉和铅对彼此的抑制作用有所减弱.吉布斯自由能变△G°为负值表明镉和铅吸附反应为自发反应;△H°为正值衰明土壤对镉和铅的吸附为吸热反应.单一存在时,镉在填土和红壤中的主要作用力分别为氢键和范德华力;而铅在壤土和红壤中的主要作用力均为范德华力.复合共存时,镉和铅的主要作用力发生改变.     

Zinc Sorption in Sandy Soils from Central Vietnam as a Function of Soil Characteristics

Zinc (Zn) sorption curves were established for 11 cultivated sandy soils from central Vietnam. Soil samples (10 g) were equilibrated with 5 mM calcium chloride (CaCl₂) solutions (50 mL) at five zinc chloride (ZnCl₂) concentrations (0 to 80 mg Zn L^–1). The experimental sorption data were fitted with the Freundlich equation. The amounts of Zn sorbed by soil (Q_Zn) at different Zn concentrations in the equilibrium solution (C_Zn) were closely related to cation exchange capacity (CEC) and pH, that is, to the available exchange sites at given pH values. More specifically, an excellent correlation was found between Zn sorption and exchangeable calcium (Ca_ex), which evidently also depends on CEC and pH. A unique equation was proposed to predict Q_Zn from C_Zn and Ca_ex in the range of Zn loading covered in our research, that is, from traces to Q_Zn ≈ 60 mg Zn kg^–1.     

Changes in Isoelectric Point as Affected by Anion Adsorption on Two Brazilian Oxisols

Abstract

Iron and aluminum oxides are widespread in tropical environments and increase soil's isoelectric point (IP). Anion adsorption modifies the IP and the surface charge of oxidic materials. This study evaluated IP changes on A‐ and B‐horizon samples of two Brazilian Oxisols upon reaction with acetate, citrate, oxalate, phosphate and sulfate (1 mmol L^?1; soil–solution 1∶100; pH 5.5; ionic strength 30 mmol L^?1 as NaCl). Most anions seemed to be specifically adsorbed, because the IP decreased after the reaction with the ligands. The IP of natural and of the acetate‐, citrate‐, oxalate‐, phosphate‐, and sulfate‐treated samples followed the order: Red Latosol‐A: 2.89,2.86, <2.50, 2.63, 2.79, 2.86; Red Latosol‐B: 5.92, 5.89, 2.79, 3.42, 3.36, 5.84; Red‐yellow Latosol‐A: 2.89, 2.79, <2.50, <2.50, 2.66, 2.89; and Red‐yellow Latosol‐B: 6.38, 6.29, 3.06, 4.36, 3.69, 6.15. The decrease in IP caused by citrate, oxalate, and Phosphate is relevant because this interferes with charge‐dependent soil reactions.     

Relative Agronomic Effectiveness of phosphate rocks and P adsorption characteristics of an Oxic Rhodustalf in Eastern India

The Relative Agronomic Effectiveness (RAE) of rock phosphates as compared to water soluble Triple Super Phosphate was measured on direct, residual, and cumulative application of the P fertilizers in a field experiment with rice on an Oxic‐Rhodustalf in the eastern plateau region of India. The fertilizers were Morocco Rock Phosphate (MORP), Mussoorie Rock Phosphate (MRP), Partially Acidulated Rock Phosphate (PARP), and Triple Super Phosphate (TSP). The RAE of the rock phosphates were lower for direct application (54–80 %) and cumulative application (70–93 %) of P but roughly equal or larger for the residual effect (92–142 %) as compared to TSP. The P adsorption characteristic of the experimental soil conformed to the linear relationship of both Freundlich and Langmuir isotherm equation. The adsorption data when plotted according to Langmuir equation deviated from a single linear relationship at higher concentration (10 μg ml^–1), thereby giving two adsorption maximum values ( 68.49 μg g^–1 and 256.41 μg g^–1) and binding energies ( 2.86 ml μg^–1 and 0.089 ml μg^–1) for the soil. Two populations of P adsorption site with widely different affinity for P probably existed in the soil.     

Geochemistry of Manganese in Neutral to Alkaline Soils of Punjab,Northwest India and Its Availability to Wheat and Rice Plants

Manganese (Mn) release in 18 soil–water suspensions after their equilibration for 24 and 240 h periods at 25°C was studied in a laboratory experiment. Total dissolved Mn released into the soil solution was observed to increase from a range of 0.03–0.41 mg L^?1 (mean = 0.13 mg L^?1) to a range of 0.45–44.44 mg L^?1 (mean = 22.40 mg L^?1) with the increase in incubation periods from 24 to 240 h, respectively. The increase in Mn released was observed to be related with the redox potential (pe) induced by incubation conditions. After 24 h of equilibration period, pe of soil–water suspension ranged from ?1.75 to 0.77 (mean = ?0.24). Increasing the incubation period to 240 h, pe of soil–water suspensions declined in the range of ?4.49 to ?2.74 (mean = ?3.29). Laboratory results of redox pe and corresponding dissolved manganese concentrations of some soil–water equilibrated systems were compared with the leaf Mn content in wheat and rice plants grown in the fields, from where soil samples were collected for laboratory experiment. These results demonstrated that decline in pe due to longer equilibration period (240 h) of soil–water systems in the laboratory experiment or keeping standing water for a couple of weeks in the fields for cultivation of rice crop results in higher release of Mn and eventually its higher uptake in rice than in wheat plants. Leaf manganese content in rice ranged from 94 to 185 mg kg^?1, which was markedly higher than its range from 25 to 62 mg kg^?1 found in the wheat grown at 10 different sites. Pourbaix diagrams were drawn for different soil–water systems containing carbonate, phosphate, or sulfate along with manganese. The presence of carbonate and phosphate anions along with manganese oxides minerals in the soil–water systems of all soils results in its precipitation as MnCO₃ and MnHPO₄, respectively, in both oxidized and reduced soil field environment. In Punjab, wheat and rice crops are generally cultivated on soils heavily fertilized with P fertilizers. The presence of phosphate anion with manganese oxides minerals in the soil–water systems of all soils results in the precipitation MnHPO₄ in both oxidized and reduced soil field environment. Thus, in P-fertilized soil, MnHPO₄ compound is even more predominant than aqueous Mn²⁺ and its solubility actually controlled the availability of Mn²⁺ to plants.     

Distribution and Availability of Zinc and Copper in Benchmark Soils of Pernambuco State,Brazil

Abstract

The benchmark soils collection of Pernambuco state contain 13 of the 14 soil orders of the Brazilian System of Soil Classification. Thus, information on zinc (Zn) and copper (Cu) status in such soils is useful as a reference of micronutrient distribution and availability in a representative set of Brazilian soils. The present work was performed to assess Zn and Cu distribution into operationally defined fractions of benchmark soils of Pernambuco state. In addition, chemical extractants, with contrasting chemical properties, were used to assess the availability of these micronutrients to relate such values with fertility guidelines concentrations and with the fractions defined by the sequential extraction. The results demonstrated that the organic matter was the most important fraction retaining Zn and Cu in the studied soils, as indicated by the sequential extraction. The Zn availability in the majority of the soils (90% of the samples) is sufficient to meet the requirement of the major field crops, although the available Cu concentrations are below the critical levels for plant growth in 46% of the analyzed samples. Mehlich‐1 extractant appeared to be the most efficient in predicting the availability of Zn in the soils because of its better correlation with exchangeable and organic fractions. DTPA and Mehlich‐3 were the most efficient extractants for the evaluation of Cu availability, as suggested by the better correlation with organic matter, which is the main pool of available Cu in the soils.     

Extractability and Transformation of Copper and Zinc Added to Tropical Savanna Soil under Long-Term Pasture

The extractability and slow reactions of copper (Cu) and zinc (Zn) in a weathered savanna soil under Brachiaria decumbens, Digitaria smutsii, and Stylosanthes guianensis pastures were determined in a laboratory incubation study using a sequential extraction to remove operationally defined fractions of the metals, consisting of exchangeable, organically bound, precipitate [occluded in aluminum (Al) and iron (Fe) oxides], and residual metal fractions. The soils from the pasture fields were spiked with 100 mg Cu kg^–1 soil and 200 mg Zn kg^–1 soil for 24 weeks. Copper and Zn extractable with 1 N potassium nitrate (KNO₃) solution decreased exponentially with time but reached a steady state after 2–3 weeks. The concentrations of Cu and Zn exchangeable with potassium (K) were greater in the Digitaria smutsii field soil than Brachiaria decumbens and Stylosanthes guianensis field soils. The exchangeability of added Cu and Zn (indexed Mⁿ⁺ _(exch)) with time was described by a simple exponential decay equation: Mⁿ⁺ _(exch) = αe^βt, where α is a constant, β is a coefficient that defines the rate of transformation of added Cu and Zn from the exchangeable to nonexchangeable pools, and t is time. The β values for Cu (0.040–0.076 mg kg^–1 d^–1) were almost 10 times greater than those of Zn (0.005–0.007 mg kg^–1 d^–1). Sequential extraction of added Cu and Zn indicated that between 26 and 30% of the total Cu and between 19 and 30% of the total Zn were associated with organic matter. Similarly, between 35 and 38% of total Cu and between 47 and 60% of total Zn were associated with Fe, Al, and manganese (Mn) oxides. The differential capacity of the pasture fields to transform added Cu and Zn from exchangeable and labile form to nonlabile and nonexchangeable form appears to be governed by organic matter (OM), pH, and active Fe ratio in the pasture field soils.     

模拟酸雨对荔枝果园土壤磷素等温吸附与解吸特性的影响

采用等温吸附试验方法研究了模拟酸雨对荔枝果园土壤磷的吸附与解吸特性的影响。试验结果表明,不同处理间土壤对磷的最大吸附量(Xm)为pH2.5>pH4.5>CK=pH6.5,其中pH2.5的酸雨淋溶处理对磷的最大吸附量(Xm)与其它处理间差异显著;土壤吸附磷的解吸量(Xd)分别与相应的吸附量(X)和原平衡溶液浓度(C)呈显著的指数相关和线性相关,随着土壤对吸附量的增加,土壤磷的解吸量呈指数增长。     

黄棕壤中活性有机碳对Cu吸附的影响

通过盐酸酸化法来去除4种不同利用方式黄棕壤的活性有机碳（AOC）,得到相对稳定的有机碳土壤,用于研究去除活性有机碳前后对Cu2＋吸附行为的影响。结果表明,黄棕壤去除有机碳前后,对Cu2＋吸附量与平衡液浓度的关系符合Langmuir方程和Freundlich方程,其拟合都呈现极显著相关（P〈0.01）,去除AOC后,黄棕壤各层次对Cu2＋的最大吸附量明显降低,是原土Cu2＋最大吸附量的10%～30%。盐酸酸化法对4种不同利用方式的黄棕壤有机碳的去除率为30%～75%,对Cu2＋吸附的减少率为54%～86%。去除活性有机碳前后,有机碳含量与对Cu2＋的吸附量都呈显著线性相关。土壤有机碳的去除率与对Cu2＋吸附的减少率间相关性达到极显著水平。     

Distribution of Zinc Fractions in Some Major Soils of India and the Impact on Nutrition of Rice

Abstract

Speciation study of microelements in soils is useful to assess their retention and release by the soil to the plant. Laboratory and greenhouse investigations were conducted for five soils of different agro‐ecological zones (viz., Bhuna, Delhi, Cooch‐Behar, Gurgaon, and Pabra) with diverse physicochemical properties to study the distribution of zinc (Zn) among the soil fractions with respect to the availability of Zn species for uptake by rice plant. A sequential extraction procedure was used that fractionated total soil Zn into water‐soluble (WS), exchangeable (EX), specifically adsorbed (SA), acid‐soluble (AS), manganese (Mn)‐oxide‐occluded (Mn‐OX), organic‐matter‐occluded (OM), amorphous iron (Fe)‐oxide‐bound (AFe‐OX), crystalline Fe‐oxide‐bound (CFe‐OX), and residual (RES) forms. There was a wide variation in the magnitude of these fractions among the soils. The studies revealed that more than 90% of the total Zn content occurred in the relatively inactive clay lattice and other mineral‐bound form (RES) and that only a small fraction occurred in the forms of WS, EX, OM, AFe‐OX, and CFe‐OX. Rice (Oryza sativa L.) cultivars differ widely in their sensitivity to Zn deficiency. Results suggested that Zn in water‐soluble, organic complexes, exchange positions, and amorphous sesquioxides were the fractions (pools) that played a key role in the uptake of Zn by the rice varieties (viz., Pusa‐933‐87‐1‐11‐88‐1‐2‐1, Pusa‐44, Pusa‐834, Jaya, and Pusa‐677). Isotopic ally exchangeable Zn (labile Zn) was recorded higher in Typic Ustrochrept of Pabra soil, and uptake of Zn by rice cultivars was also higher in this soil. The kinetic parameters such as maximum influx at high concentrations (I_max) and nutrient concentration in solution where influx is one half of I_max (K_m) behaved differentially with respect to varieties. The highest I_max value recorded was 9.2×10^?7 µmol cm^?2 s^?1 at the 5 mg kg^?1 Zn rate for Pusa‐933‐87‐1‐11‐88‐1‐2‐1, and the same was lowest for Pusa‐44, being 4.6×10^?7 µmol cm^?2 s^?1 at the 5 mg kg^?1 Zn rate. The K_m value was highest for Pusa‐44 (2.1×10^?4µmol cm^?2 s^?1) and lowest for Pusa‐933‐87‐1‐11‐88‐1‐2‐1 (1.20×10^?4µmol cm^?2 s^?1). The availability of Zn to rice cultivars in Typic Ustrochrepts of Bhuna and Delhi soils, which are characterized by higher activation energy and entropy factor, was accompanied by breakage of bonds or by significant structural changes.     

Zinc Transformation in a Calcareous Soil as Affected by Applied Zinc Sulfate,Vermicompost, and Incubation Time

An experiment was conducted to evaluate the effect of zinc (Zn) rates and vermicompost levels on distribution of Zn forms of a calcareous soil. After incubation periods, soil samples were air dried, and a sequential extraction scheme was used to fractionate Zn into soluble and exchangeable, bound to carbonate, organically bound, bound to manganese (Mn) oxide, bound to amorphous iron (Fe) oxide, bound to crystalline Fe oxide, and residual forms. In untreated soil, Zn was mainly in the residual fraction. Increasing rates of applied Zn significantly increased all forms of Zn. Carbonate and residual forms showed the greatest increase. Application of vermicompost significantly increased all fractions except Mn-oxide form. This increase was more pronounced for organically bound, soluble, and exchangeable forms, indicating an increase in bioavailability of soil Zn. Incubation time significantly decreased soluble, exchangeable, and organically bound forms but increased other forms of Zn, meaning a significant reduction in Zn phytoavailability in soil with time.     

向海湿地河道土壤吸附铅、镉能力的研究

利用向海湿地河道上、下游土壤样品进行了吸附铅、镉的热力学实验,结果表明土壤样品吸附铅、镉的过程符合Langmuir和Freundlich等温吸附曲线(n=8,p=0.01),吸附铅的能力约是吸附镉能力的一个数量级,下游断面土壤样品吸附铅、镉的能力明显大于上游断面,且土壤样品吸附铅、镉的最大吸附量与土壤中的细粒土壤、有机质和铁、锰氧化物含量存在显著的相关性,即土壤样品的理化性质是影响土壤吸附铅、镉能力的主要因素;同时,根据向海湿地河道上、下游土壤样品理化性质的差异,可以推测向海湿地净化污染物功能在逐渐减弱。