Effects of Organic Matter and Iron Oxides on Cation Exchange Equilibria and Potassium Selectivity in a Volcanic Ash Soil of Chile

Salazar, Itilier; Escudey, Mauricio; Guajardo, Julio; Goulding, Keith

doi:10.1081/css-120015914

Cited by 4 publications

(4 citation statements)

References 23 publications

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“…The contribution rate of Fe d to the change of soil surface electrochemical properties was lower than that of organic matter and humus (Table 7). This view is consistent with Salazar et al [44], but contrary to Ketrot et al [45], which may be due to differences in the adsorption and complexation strength of clay minerals and metal oxides on organic matter in different soils [46][47]. Therefore, there were negative correlations between the Fe d and related electrochemical properties (Table 6).…”

Section: Effects Of Soil Organic/inorganic Colloidal Properties On Soil Surface Electrochemical Properties Of Karst Rocky Desertificationsupporting

confidence: 89%

Soil Surface Electrochemical Properties in a Karst Ecosystem and Its Response to Rocky Desertification Evolution, SW China

Zhao¹,

Sheng²,

Shu-xi³

et al. 2021

Pol. J. Environ. Stud.

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Rocky desertification control is an effective way to reconstruct degraded ecosystems and restore soil function in karst areas. Soil surface electrochemical properties, including soil surface potential, surface charge density, surface electric field strength, specific surface area, and surface charge number are important indicators for evaluating agricultural soil quality and environmental carrying capacity. However, little attention has been paid to the effect of rocky desertification succession on soil electrochemical properties. In this study, we selected a sequence of rocky desertification succession (nil, slight, moderate, and severe) to study the changes in soil surface electrochemical properties during the succession of rocky desertification. Our results showed that with increasing rocky desertification intensity, soil surface charge density, surface charge intensity, specific surface area, and the numbers of surface charge decreased, while the soil surface potential increases. The results showed that humus composition, soil particle size composition, and metal oxide content were important environmental factors that determine the electrochemical properties of soil surface in a karst rocky desertification area. In terms of impact on surface charge properties, soil properties displayed an order of humus>particle size composition>metal oxides. In addition, through the comparative analysis of soil physical properties and surface electrochemical properties, it was found that the surface soil aggregates of severe rocky desertification were more likely to disintegrate when precipitation occurs, thus facing a higher risk of soil erosion. Our results showed that the electrochemical properties of soil surface decrease with the increase of rocky desertification grades, which contributed to the decline of soil water and fertilizer

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Section: Effects Of Soil Organic/inorganic Colloidal Properties On Soil Surface Electrochemical Properties Of Karst Rocky Desertificationsupporting

confidence: 89%

Soil Surface Electrochemical Properties in a Karst Ecosystem and Its Response to Rocky Desertification Evolution, SW China

Zhao¹,

Sheng²,

Shu-xi³

et al. 2021

Pol. J. Environ. Stud.

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“…of soils, statistical approaches have been previously advantageously adopted over the selective removal of each component by chemical treatment (Wright and Foss, 1972;Klamt and Sombroek, 1986). The reason being that chemical treatment can cause interference on the derived charges due to pH alterations (Salazar et al, 2002). Therefore, we used partial regression coefficient values and the content of soil organic matter, clay and CEC eff.…”

Section: Assessment Of the Confounding Effect Of Organicmentioning

confidence: 99%

A Critical Evaluation of the Relationship Between the Effective Cation Exchange Capacity and Soil Organic Carbon Content in Swiss Forest Soils

Solly¹,

Weber²,

Zimmermann³

et al. 2020

Front. For. Glob. Change

109

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An improved identification of the environmental variables that can be used to predict the content of soil organic carbon (SOC) stored belowground is required to reduce uncertainties in estimating the response of the largest terrestrial carbon reservoir to environmental change. Recent studies indicate that some metal cations can have an active role in the stabilization of SOC, primarily by coordinating the interaction between soil minerals and organic matter through cation bridging and by creating complexes with organic molecules when their hydration shells are displaced. The effective cation exchange capacity (CEC eff.) is a measure that integrates information about available soil surfaces to which metal cations are retained. Therefore, we critically tested the relationship between CEC eff. and SOC content using regression analyses for more than 1000 forest sites across Switzerland, spanning a unique gradient of mean annual precipitation (640-2500 mm), elevation (277-2207 m a.s.l), pH (2.8-8.1) and covering different geologies and vegetation types. Within these sites, SOC content is significantly related to CEC eff., in both topsoils and subsoils. Our results demonstrate that, on a pH-class average, in Swiss forest topsoils (<30 cm depth) there is a strong confounding effect of soil organic matter contributing between 35 and 50% to the total CEC eff. In subsoils, soil organic matter has a negligible contribution to CEC eff., and the variation of CEC eff. is associated to the presence of inorganic surfaces such as clay content as well as iron-and aluminum-oxides and hydroxides. At pH > 5.5, between 59 and 83% of subsoil CEC eff. originates from exchangeable calcium, whereas in acidic soils exchangeable aluminum contributes between 21 and 44% of the CEC eff. Exchangeable iron contributes to less than 1% of the variability in CEC eff. Overall this study indicates that in Swiss forests subsoils, CEC eff. strongly reflects the surface of soil minerals to which SOC can be bound by metal cations. The strength of the relationship between CEC eff. and SOC content depends on the pH of the soil, with the highest amount of variation of SOC content explained by CEC eff. in subsoils with pH > 5.5.

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“…All of the soils are composed of at least 65% sandy fraction, which confirms their origin and slight weathering. This information is of particular significance for the chemical and physicochemical studies carried out, because even though the existence of cation exchange has been shown to exist between the solution and the sandy soil fraction (Barticevic et al 1975), it is the clay fraction that is mainly responsible for the occurrence of the cation exchange processes, together with the organic matter content (Salazar et al 2002).…”

Section: Chemical Characterisationmentioning

confidence: 99%

“…Approximations such as Gaines and Thomas (Gaines and Thomas 1953) and Rothmund-Kornfeld (Bond 1995) have been used to gain an insight into the exchange behaviour characteristics, mainly of Andepts and other inorganic fractions of soils in Chile. (Escudey and Galindo 1988;Escudey et al 1997Escudey et al , 2001Escudey et al , 2002Salazar et al 2002). However, these approximations have been applied on soils with high Na and saline content, which might turn binary equilibria into ternary ones.…”

Section: Introductionmentioning

confidence: 99%

K - Ca - Mg binary cation exchange in saline soils from the north of Chile

2008

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The selectivities of the K–Ca and K–Mg cation exchange reactions were studied in batch experiments carried out with 7 Chilean saline sandy soils with low organic matter (OM) content, and rich in quartz and halite, by using the experimental Gaines and Thomas procedure and the semi-empirical Rothmund–Kornfeld approach. The soils present high reactivity to the exchange process in terms of CEC and a preference order from the surface for the cation of K > Ca > Mg. In addition, the existence of different types of exchange sites was determined; some were specific for determined cations and others presented free competition. The proposed exchange reaction for both equilibria was thermodynamically possible and the studied cations presented a decreasing mobility order K > Ca > Mg, which follows the increasing order of hydrated ionic radii. As for the Rothmund–Kornfeld semi-empirical approach, it can be employed on soils classified as Aridisol due to good fit with the experimental data. On the other hand, the Gaines and Thomas approach is only experimentally applicable since poses some restrictions concerning to salinity and carbonate contents in the studied soils.

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Effects of Organic Matter and Iron Oxides on Cation Exchange Equilibria and Potassium Selectivity in a Volcanic Ash Soil of Chile

Cited by 4 publications

References 23 publications

Soil Surface Electrochemical Properties in a Karst Ecosystem and Its Response to Rocky Desertification Evolution, SW China

Soil Surface Electrochemical Properties in a Karst Ecosystem and Its Response to Rocky Desertification Evolution, SW China

A Critical Evaluation of the Relationship Between the Effective Cation Exchange Capacity and Soil Organic Carbon Content in Swiss Forest Soils

K - Ca - Mg binary cation exchange in saline soils from the north of Chile

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