Soil Organic Matter and Phosphate Sorption on Natural and Synthetic Fe Oxides under in Situ Conditions

2019 ◽  
Vol 53 (22) ◽  
pp. 13081-13087 ◽  
Author(s):  
Kristof Dorau ◽  
Lydia Pohl ◽  
Christopher Just ◽  
Carmen Höschen ◽  
Kristian Ufer ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Phosphate Sorption ◽  
Fe Oxides ◽  
In Situ Conditions ◽  
Natural And Synthetic

Soil organic matter and phosphate sorption on natural and synthetic Fe oxides under in situ conditions

2020 ◽  
Author(s):  
Lydia Pohl ◽  
Kristof Dorau ◽  
Christopher Just ◽  
Carmen Höschen ◽  
Kristian Ufer ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Oxide Coating ◽  
Redox Status ◽  
Fe Oxide ◽  
Fe Oxides ◽  
Mn Oxide ◽  
Mn Oxides ◽  
Natural And Synthetic

<p>In redoximorphic soils, iron (Fe) and manganese (Mn) oxides undergo reduction with subsequent oxidation of their reduced counterparts (Fe<sup>2+</sup> and Mn<sup>2+</sup>) impacting nutrient sorption and the stability of soil organic matter (SOM). One tool to investigate the soil redox status is the indicator of reduction in soils (IRIS) method. Thereby, synthetic Fe and Mn oxides are coated onto polyvinyl chloride (PVC) bars, which are typically installed for an operator-defined period in the soil. After removal of the bars we studied organo-mineral associations, which have been formed under field conditions on the surface of the coated bars.</p><p>In this study, each one Mn and Fe oxide-coated redox bar were installed for 30 days in a Mollic Gleysol. A previous study revealed, that the Mn oxide coating facilitated a non-enzymatic redox reaction under anoxic conditions, while Fe<sup>2+</sup> from the soil solution is oxidized to Fe<sup>3+</sup> along the Mn oxide coating and Mn<sup>2+</sup> is removed from the PVC surface [1]. In consequence, in situ Fe oxides formed along the Mn oxide coatings and were further considered as ‘natural’ Fe oxides. This enables us to differentiate between sorption occurring onto the surfaces of ‘synthetic’ Fe oxides from the Fe bar versus ‘natural’ formed Fe oxides along the Mn bar. They were analysed by nanoscale secondary ion mass spectrometry (NanoSIMS) to study the distribution of Fe (<sup>56</sup>Fe<sup>16</sup>O<sup>−</sup>), SOM (<sup>12</sup>C<sup>14</sup>N<sup>−</sup>), and phosphorus (<sup>31</sup>P<sup>16</sup>O<sub>2</sub><sup>−</sup>). NanoSIMS is a spectromicroscopic technique offering a high lateral resolution of about 100 nm, while having a great sensitivity for light elements. In contrast to classic bulk analysis, it offers the possibility to examine the spatial distribution of SOM and phosphorous at the microscale within the intact organo-mineral matrix. </p><p>Image analysis of individual Fe oxide particles revealed a close association of Fe, SOM, and P resulting in coverage values up to 71% for synthetic and natural iron oxides. Furthermore, ion ratios between sorbent (<sup>56</sup>Fe<sup>16</sup>O<sup>−</sup>) and sorbate (<sup>12</sup>C<sup>14</sup>N<sup>−</sup>; <sup>31</sup>P<sup>16</sup>O<sub>2</sub><sup>−</sup>) were smaller along the natural oxides when compared with those for synthetic Fe oxides. We conclude that both natural and synthetic Fe oxides rapidly sequestered SOM and P (i.e., within 30 days) but that newly, natural formed Fe oxides sorbed more SOM and P than synthetic Fe oxides.</p><p> </p><p>[1] Dorau, K.; Eickmeier, M.; Mansfeldt, T. Comparison of Manganese and Iron Oxide-Coated Redox Bars for Characterization of the Redox Status in Wetland Soils. Wetlands 2016, 36, 133–144.</p>

scholarly journals Modeling the vertical soil organic matter profile using Bayesian parameter estimation

2012 ◽  
Vol 9 (8) ◽  
pp. 11239-11292 ◽  
Author(s):  
M. C. Braakhekke ◽  
T. Wutzler ◽  
C. Beer ◽  
J. Kattge ◽  
M. Schrumpf ◽  
...  
Keyword(s):  
Organic Matter ◽  
Parameter Estimation ◽  
Soil Organic Matter ◽  
Soil Carbon ◽  
Mineral Soil ◽  
Bayesian Parameter Estimation ◽  
Additional Information ◽  
Root Litter ◽  
In Situ Conditions

Abstract. The vertical distribution of soil organic matter (SOM) in the profile may constitute a significant factor for soil carbon cycling. However, the formation of the SOM profile is currently poorly understood due to equifinality, caused by the entanglement of several processes: input from roots, mixing due to bioturbation, and organic matter leaching. In this study we quantified the contribution of these three processes using Bayesian parameter estimation for the mechanistic SOM profile model SOMPROF. Based on organic carbon measurements, 13 parameters related to decomposition and transport of organic matter were estimated for two temperature forest soils: an Arenosol with a mor humus form (Loobos, The Netherlands), and a Cambisol with mull type humus (Hainich, Germany). Furthermore, the use of the radioisotope 210Pbex as tracer for vertical SOM transport was studied. For Loobos the calibration results demonstrate the importance of liquid phase transport for shaping the vertical SOM profile, while the effects of bioturbation are generally negligible. These results are in good agreement with expectations given in situ conditions. For Hainich the calibration offered three distinct explanations for the observations (three modes in the posterior distribution). With the addition of 210Pbex data and prior knowledge, as well as additional information about in situ conditions, we were able to identify the most likely explanation, which identified root litter input as the dominant process for the SOM profile. For both sites the organic matter appears to comprise mainly adsorbed but potentially leachable material, pointing to the importance of organo-mineral interactions. Furthermore, organic matter in the mineral soil appears to be mainly derived from root litter, supporting previous studies that highlighted the importance of root input for soil carbon sequestration. The 210Pbex measurements added only slight additional constraint on the estimated parameters. However, with sufficient replicate measurements and possibly in combination with other tracers, this isotope may still hold value as tracer for a SOM transport.

scholarly journals Modeling the vertical soil organic matter profile using Bayesian parameter estimation

2013 ◽  
Vol 10 (1) ◽  
pp. 399-420 ◽  
Author(s):  
M. C. Braakhekke ◽  
T. Wutzler ◽  
C. Beer ◽  
J. Kattge ◽  
M. Schrumpf ◽  
...  
Keyword(s):  
Organic Matter ◽  
Parameter Estimation ◽  
Soil Organic Matter ◽  
Soil Carbon ◽  
Mineral Soil ◽  
Bayesian Parameter Estimation ◽  
Root Litter ◽  
In Situ Conditions ◽  
Matter Transport

Abstract. The vertical distribution of soil organic matter (SOM) in the profile may constitute an important factor for soil carbon cycling. However, the formation of the SOM profile is currently poorly understood due to equifinality, caused by the entanglement of several processes: input from roots, mixing due to bioturbation, and organic matter leaching. In this study we quantified the contribution of these three processes using Bayesian parameter estimation for the mechanistic SOM profile model SOMPROF. Based on organic carbon measurements, 13 parameters related to decomposition and transport of organic matter were estimated for two temperate forest soils: an Arenosol with a mor humus form (Loobos, the Netherlands), and a Cambisol with mull-type humus (Hainich, Germany). Furthermore, the use of the radioisotope 210Pbex as tracer for vertical SOM transport was studied. For Loobos, the calibration results demonstrate the importance of organic matter transport with the liquid phase for shaping the vertical SOM profile, while the effects of bioturbation are generally negligible. These results are in good agreement with expectations given in situ conditions. For Hainich, the calibration offered three distinct explanations for the observations (three modes in the posterior distribution). With the addition of 210Pbex data and prior knowledge, as well as additional information about in situ conditions, we were able to identify the most likely explanation, which indicated that root litter input is a dominant process for the SOM profile. For both sites the organic matter appears to comprise mainly adsorbed but potentially leachable material, pointing to the importance of organo-mineral interactions. Furthermore, organic matter in the mineral soil appears to be mainly derived from root litter, supporting previous studies that highlighted the importance of root input for soil carbon sequestration. The 210Pbex measurements added only slight additional constraint on the estimated parameters. However, with sufficient replicate measurements and possibly in combination with other tracers, this isotope may still hold value as tracer for SOM transport.

In situ photo-polymerization of soil organic matter by heterogeneous nano-TiO2 and biomimetic metal-porphyrin catalysts

2016 ◽  
Vol 52 (4) ◽  
pp. 585-593 ◽  
Author(s):  
Assunta Nuzzo ◽  
Elisa Madonna ◽  
Pierluigi Mazzei ◽  
Riccardo Spaccini ◽  
Alessandro Piccolo
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Metal Porphyrin ◽  
Nano Tio2 ◽  
Photo Polymerization

Effective carbon sequestration in Italian agricultural soils by in situ polymerization of soil organic matter under biomimetic photocatalysis

2018 ◽  
Vol 29 (3) ◽  
pp. 485-494 ◽  
Author(s):  
Alessandro Piccolo ◽  
Riccardo Spaccini ◽  
Vincenza Cozzolino ◽  
Assunta Nuzzo ◽  
Marios Drosos ◽  
...  
Keyword(s):  
Organic Matter ◽  
Carbon Sequestration ◽  
Soil Organic Matter ◽  
In Situ Polymerization ◽  
Agricultural Soils

Quantifying in situ and modeling net nitrogen mineralization from soil organic matter in arable cropping systems

2017 ◽  
Vol 111 ◽  
pp. 44-59 ◽  
Author(s):  
Hugues Clivot ◽  
Bruno Mary ◽  
Matthieu Valé ◽  
Jean-Pierre Cohan ◽  
Luc Champolivier ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Nitrogen Mineralization ◽  
Cropping Systems ◽  
Net Nitrogen Mineralization ◽  
Quantifying In
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