The role of poorly crystalline iron oxides in the stability of soil aggregate-associated organic carbon in a rice–wheat cropping system

Huang, Xiaolei; Jiang, Hong; Li, Yong; Ma, Yucui; Tang, Haiyan; Wei, Ran; Shen, Qirong

doi:10.1016/j.geoderma.2016.05.011

Cited by 81 publications

(22 citation statements)

References 45 publications

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“…Some chemical extraction procedures can be useful in the analysis of Fe oxides. However, this is expensive, timeconsuming, and can complicate our scienti c interpretation of the soil by changing the chemical equilibrium between soil solution and solid phases in soil specimens [15,16]. us, these conventional analyses are not appropriate for larger scale soil studies, and we must use an alternative method to target and characterize soil minerals.…”

Section: Introductionmentioning

confidence: 99%

Visible and Near-Infrared Reflectance Spectroscopy for Investigating Soil Mineralogy: A Review

Fang

Hong

Zhao

et al. 2018

Journal of Spectroscopy

114

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Clay minerals are the most reactive and important inorganic components in soils, but soil mineralogy classifies as a minor topic in soil sciences. Revisiting soil mineralogy has been gradually required. Clay minerals in soils are more complex and less well crystallized than those in sedimentary rocks, and thus, they display more complicated X-ray diffraction (XRD) patterns. Traditional characterization methods such as XRD are usually expensive and time-consuming, and they are therefore inappropriate for large datasets, whereas visible and near-infrared reflectance spectroscopy (VNIR) is a quick, cost-efficient, and nondestructive technique for analyzing soil mineralogic properties of large datasets. The main objectives of this review are to bring readers up to date with information and understanding of VNIR as it relates to soil mineralogy and attracts more attention from a wide variety of readers to revisit soil mineralogy. We begin our review with a description of fundamentals of VNIR. We then review common methods to process soil VNIR spectra and summary spectral features of soil minerals with particular attention to those <2 μm fractions. We further critically review applications of chemometric methods and related model building in spectroscopic soil mineral studies. We then compare spectral measurement with multivariate calibration methods, and we suggest that they both produce excellent results depending on the situation. Finally, we suggest a few avenues of future research, including the development of theoretical calibrations of VNIR more suitable for various soil samples worldwide, better elucidation of clay mineral-soil organic carbon (SOC) interactions, and building the concept of integrated soil mapping through combined information (e.g., mineral composition, soil organic matter-SOM, SOC, pH, and moisture).

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Section: Introductionmentioning

confidence: 99%

Visible and Near-Infrared Reflectance Spectroscopy for Investigating Soil Mineralogy: A Review

Fang

Hong

Zhao

et al. 2018

Journal of Spectroscopy

114

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“…A substantial body of research has indicated that iron oxides play an important role in preserving organic carbon in sediments (Lalonde et al, ; Ma et al, ; Shields et al, ), soils of permafrost regions (Mu et al, ; Salvadó et al, ), forest soils (Zhao et al, ) and agricultural soils (Drosos et al, ; Drosos & Piccolo, ; Huang et al, , ). However, little information about the quantitative characterization of Fe‐bound OC across different agricultural soils and its governing factors has been available.…”

Section: Introductionmentioning

confidence: 99%

Iron oxides selectively stabilize plant‐derived polysaccharides and aliphatic compounds in agricultural soils

Wan

et al. 2019

European J Soil Science

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A strong link exists between iron oxides and soil organic carbon (SOC). However, the role of iron oxides in the preservation of SOC in agricultural soil remains poorly understood. In this study, we comprehensively examined the concentration, molecular composition and biological sources of iron oxide‐bound organic carbon (Fe‐bound OC) in arable soils collected from 12 sites in central and east China. The results indicated that 6.2–31.2% of the SOC was bound to iron oxides in agricultural soil and that the binding mechanisms varied from adsorption in most soils to coprecipitation in those with a large content of organic carbon. The distribution of Fe‐bound OC showed no clear variation in relation to site, but Fe‐bound OC reached a peak in soils with an annual mean temperature of 16.4°C. Correlation analysis demonstrated that TOC might be the main determinant for the amount of Fe‐bound OC and that the binding mechanism is influenced by both TOC and the active Fe ratio. Comprehensive studies of C/N, 13C isotope and synchrotron radiation‐based Fourier transform infrared (SR‐FTIR) spectroscopy showed that iron oxides selectively protected plant‐derived aliphatic compounds and polysaccharides in agricultural soil. This study revealed the quantitative characterization, biological sources and molecular composition of Fe‐bound OC in arable soils, which provides useful information for evaluating and managing the global C cycle under the framework of climate change.

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“…It has also been reported that reactive Fe concentrations (or SRO minerals) are significantly increased by organic amendments in both upland and paddy soils (Zhou et al, 2009;Yan et al, 2013;Huang X. et al, 2016;Yu et al, 2017;Wen et al, 2018;Wang et al, 2019). Although this observation is confused by the definition of reactive Fe minerals, it is interesting that the amounts of Fe extracted by acid ammonium oxalate (i.e., Fe o ) in Table 1 were consistently greater under organic amendments in all paddy soils, but not in upland soils, whereas long-term organic amendments increased the Fe o−p values (which is the difference between Fe o and Fe p ), in upland soils.…”

Section: Soil Physicochemical Properties Iron Fractions In Field Sammentioning

confidence: 94%

Effects of Organic Amendments on the Transformation of Fe (Oxyhydr)Oxides and Soil Organic Carbon Storage

et al. 2019

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Organic amendments from animal production are commonly used for promoting soil fertility, and their impacts on the residual soil organic carbon (SOC) are of both agricultural and environmental interest. Iron (Fe) in the form of (oxyhydr)oxides has been proposed to play a critical role in long-term SOC preservation by forming Fe-organic associations, though currently a comprehensive understanding of how these Fe-organic associations are regulated by long-term organic amendments is limited. Here, we synthesize information to link Fe (oxyhydr)oxides, SOC sequestration, and long-term organic inputs from both field and laboratory studies. The results show that vigorous Fe mobilization can be regulated by long-term application of organic amendments, and these organically amended soils contained significantly higher concentrations of poorly crystalline Fe that was closely related to SOC storage in both upland and paddy soils. Potential mechanisms are proposed as follows: (1) DOM from the organically amended soils is more likely to co-precipitate with poorly crystalline Fe, and DOM from the inorganically fertilized soils is to a larger extent adsorbed on poorly crystalline Fe. The co-precipitated Fe-OM complexes are more resistant to desorption than the adsorbed OM. (2) DOM extracts from soils treated with organic amendments exhibit a stronger inhibitory effect on the crystallization of poorly crystalline Fe than DOM from inorganically fertilized soils, which may be the consequence of increased numbers of aromatic functional groups. Organic acids in root exudates increased soil mineral availability and the formation of poorly crystalline minerals. Compared to inorganic fertilizers, organic amendments significantly increase (>20%, p < 0.05) the concentration of poorly crystalline minerals in the presence of actual roots. (3) Microbially mediated Fe cycling is strongly linked to the Fe mineralogy in soils, and regulated by long-term organic amendments. Greater consumption of poorly crystalline

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The role of poorly crystalline iron oxides in the stability of soil aggregate-associated organic carbon in a rice–wheat cropping system

Cited by 81 publications

References 45 publications

Visible and Near-Infrared Reflectance Spectroscopy for Investigating Soil Mineralogy: A Review

Visible and Near-Infrared Reflectance Spectroscopy for Investigating Soil Mineralogy: A Review

Iron oxides selectively stabilize plant‐derived polysaccharides and aliphatic compounds in agricultural soils

Effects of Organic Amendments on the Transformation of Fe (Oxyhydr)Oxides and Soil Organic Carbon Storage

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