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Subcritical water extraction to isolate kinetically different soil nitrogen fractions

(2013) BIOGEOSCIENCES. 10(11). p.7435-7447
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Abstract
Soil organic N is largely composed of inherently biologically labile proteinaceous N and its persistence in soil is mainly explained by stabilization through binding to minerals and other soil organic matter (SOM) components at varying strengths. In order to separate kinetically different soil N fractions we hypothesize that an approach which isolates soil N fractions on the basis of bonding strength is required, rather than employing chemical agents or physical methods. We developed a sequential subcritical water extraction (SCWE) procedure at 100, 150 and 200 degrees C to isolate SOM fractions. We assessed these SCWE N fractions as predictors for aerobic and anaerobic N mineralization measured from 25 paddy soil cores in incubations. SCWE organic carbon (SCWE OC) and N (SCWE N) increased exponentially with the increase of temperature and N was extracted preferentially over OC. The efficiency of SCWE and the selectivity towards N were both lower in soils with increasingly reactive clay mineralogy. Stepwise linear regression found no relations between the SCWE fractions and the anaerobic N mineralization rate but instead with pH and a model parameter describing the temperature dependency of SCWE extraction. Both were linked to texture, mineralogy and content of pedogenic oxides, which suggests an indirect relation between anaerobic NH4+ release and these edaphic soil factors. N mineralization appeared to be largely decoupled from SOM quantity and quality. From the present study on young paddy soils low in pedogenic oxides and with high fixed NH4+ content we cannot infer the performance of SCWE to isolate bio-available N in more developed upland soils. There may be potential to separate kinetically different SOM pools from upland soils because 1 degrees for aerobic N mineralization at 100-150 degrees C SCWE N was the best predictor; and 2 degrees SCWE selectively extracted N over C and this preference depended on the mineralogical composition. Hence N fractions differing in bonding strength with minerals or SOM might be isolated at different temperatures, and specifically this association has frequently been found a prominent stabilization mechanism of N in temperate region cropland soils.
Keywords
ORGANIC-MATTER, SUBMERGED RICE SOILS, PADDY SOILS, AVAILABILITY INDEXES, MINERALIZABLE NITROGEN, AMMONIUM PRODUCTION, CONTAMINATED SOIL, MANAGEMENT, FIXATION, RELEASE

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MLA
Sleutel, Steven, et al. “Subcritical Water Extraction to Isolate Kinetically Different Soil Nitrogen Fractions.” BIOGEOSCIENCES, vol. 10, no. 11, 2013, pp. 7435–47, doi:10.5194/bg-10-7435-2013.
APA
Sleutel, S., Kader, M. A., Demeestere, K., Walgraeve, C., Dewulf, J., & De Neve, S. (2013). Subcritical water extraction to isolate kinetically different soil nitrogen fractions. BIOGEOSCIENCES, 10(11), 7435–7447. https://doi.org/10.5194/bg-10-7435-2013
Chicago author-date
Sleutel, Steven, MD Abdul Kader, Kristof Demeestere, Christophe Walgraeve, Jo Dewulf, and Stefaan De Neve. 2013. “Subcritical Water Extraction to Isolate Kinetically Different Soil Nitrogen Fractions.” BIOGEOSCIENCES 10 (11): 7435–47. https://doi.org/10.5194/bg-10-7435-2013.
Chicago author-date (all authors)
Sleutel, Steven, MD Abdul Kader, Kristof Demeestere, Christophe Walgraeve, Jo Dewulf, and Stefaan De Neve. 2013. “Subcritical Water Extraction to Isolate Kinetically Different Soil Nitrogen Fractions.” BIOGEOSCIENCES 10 (11): 7435–7447. doi:10.5194/bg-10-7435-2013.
Vancouver
1.
Sleutel S, Kader MA, Demeestere K, Walgraeve C, Dewulf J, De Neve S. Subcritical water extraction to isolate kinetically different soil nitrogen fractions. BIOGEOSCIENCES. 2013;10(11):7435–47.
IEEE
[1]
S. Sleutel, M. A. Kader, K. Demeestere, C. Walgraeve, J. Dewulf, and S. De Neve, “Subcritical water extraction to isolate kinetically different soil nitrogen fractions,” BIOGEOSCIENCES, vol. 10, no. 11, pp. 7435–7447, 2013.
@article{4187006,
  abstract     = {{Soil organic N is largely composed of inherently biologically labile proteinaceous N and its persistence in soil is mainly explained by stabilization through binding to minerals and other soil organic matter (SOM) components at varying strengths. In order to separate kinetically different soil N fractions we hypothesize that an approach which isolates soil N fractions on the basis of bonding strength is required, rather than employing chemical agents or physical methods. We developed a sequential subcritical water extraction (SCWE) procedure at 100, 150 and 200 degrees C to isolate SOM fractions. We assessed these SCWE N fractions as predictors for aerobic and anaerobic N mineralization measured from 25 paddy soil cores in incubations. SCWE organic carbon (SCWE OC) and N (SCWE N) increased exponentially with the increase of temperature and N was extracted preferentially over OC. The efficiency of SCWE and the selectivity towards N were both lower in soils with increasingly reactive clay mineralogy. Stepwise linear regression found no relations between the SCWE fractions and the anaerobic N mineralization rate but instead with pH and a model parameter describing the temperature dependency of SCWE extraction. Both were linked to texture, mineralogy and content of pedogenic oxides, which suggests an indirect relation between anaerobic NH4+ release and these edaphic soil factors. N mineralization appeared to be largely decoupled from SOM quantity and quality. From the present study on young paddy soils low in pedogenic oxides and with high fixed NH4+ content we cannot infer the performance of SCWE to isolate bio-available N in more developed upland soils. There may be potential to separate kinetically different SOM pools from upland soils because 1 degrees for aerobic N mineralization at 100-150 degrees C SCWE N was the best predictor; and 2 degrees SCWE selectively extracted N over C and this preference depended on the mineralogical composition. Hence N fractions differing in bonding strength with minerals or SOM might be isolated at different temperatures, and specifically this association has frequently been found a prominent stabilization mechanism of N in temperate region cropland soils.}},
  author       = {{Sleutel, Steven and Kader, MD Abdul and Demeestere, Kristof and Walgraeve, Christophe and Dewulf, Jo and De Neve, Stefaan}},
  issn         = {{1726-4170}},
  journal      = {{BIOGEOSCIENCES}},
  keywords     = {{ORGANIC-MATTER,SUBMERGED RICE SOILS,PADDY SOILS,AVAILABILITY INDEXES,MINERALIZABLE NITROGEN,AMMONIUM PRODUCTION,CONTAMINATED SOIL,MANAGEMENT,FIXATION,RELEASE}},
  language     = {{eng}},
  number       = {{11}},
  pages        = {{7435--7447}},
  title        = {{Subcritical water extraction to isolate kinetically different soil nitrogen fractions}},
  url          = {{http://dx.doi.org/10.5194/bg-10-7435-2013}},
  volume       = {{10}},
  year         = {{2013}},
}

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