Journal Article

FZJ-2017-05048

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Carbon saturation drives spatial patterns of soil organic matter losses under long-term bare fallow

Meyer, N. (Corresponding author) ; Bornemann, L. ; Welp, G. ; Schiedung, H.FZJ* ; Herbst, M.FZJ* ; Amelung, W.FZJ*

2017
Elsevier Science Amsterdam [u.a.]

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Please use a persistent id in citations: doi:10.1016/j.geoderma.2017.07.004

Abstract: Spatial controls of soil organic carbon (SOC) turnover are not well understood. We hypothesized that spatialpatterns of SOC turnover are related to carbon (C) saturation rather than to the size of measurable SOC-poolssuch as particulate organic matter (POM), determined as SOC in particle-size fractions. Therefore, we repeatedlygrid-sampled a field after one, three, seven, and eleven years under bare fallow management, which revealed aspatial gradient from high to low degrees of C saturation. We measured the contents of SOC and the contents ofSOC in coarse sand-size (2000–250 μm, POM1), fine sand-size (250–53 μm, POM2), silt-size (53–20 μm, POM3),and fine silt to clay-size fractions (nonPOM,< 20 μm), calculated the degree of C saturation from texturalproperties and nonPOM contents, and related these parameters to SOC losses. In the first year of bare fallow, thesoil contained on average 12.1 g SOC kg−1, of which 0.6 g kg−1, 1.7 g kg−1, and 2.1 g kg−1 were lost afterthree, seven, and eleven years of bare fallow, respectively. The SOC losses within eleven years were spatiallyvariable and varied between 1% and 46% relative to the initial SOC content. In support of our hypothesis, SOClosses were largest at subsites with largest degrees of C saturation (R2 =0.83). Although the POM fractionsdeclined most drastically, they only comprised 4 to 9% of bulk SOC, and they did neither correlate with norexplain spatial patterns of SOC losses. We conclude that the concept of C saturation is superior to conventionalphysical fractionation approaches for predicting spatio-temporal patterns of SOC turnover at sites with a highdegree of C saturation.

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Contributing Institute(s):

1. Agrosphäre (IBG-3)

Research Program(s):

1. 255 - Terrestrial Systems: From Observation to Prediction (POF3-255) (POF3-255)

Appears in the scientific report 2017

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Database coverage:
; BIOSIS Previews ; Current Contents - Agriculture, Biology and Environmental Sciences ; Ebsco Academic Search ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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