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The role of SOM and CaCO3 on soil aggregate development in reclaimed soils

Pihlap, Evelin; Steffens, Markus and Kögel-Knabner, Ingrid (2020) The role of SOM and CaCO3 on soil aggregate development in reclaimed soils. In: EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13644, p. 13644.

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Summary

Soil organic matter (SOM) and extracellular polymeric substances (EPS) from biological processesare considered to be major contributors in aggregate formation. But there is limited knowledge onsoil structural formation after reclamation – the step when SOM content is low and soil propertiesare mostly controlled by the parent material. In our study we used a chronosequence approach in the reclaimed open-cast mining area near Cologne, Germany to elucidate the development of soilstructure and soil organic matter during initial soil formation in a loess material. We selected sixplots with different ages of agricultural management after reclamation (0, 1, 3, 6, 12, and 24 yearsafter first seeding). In each reclaimed field 12 spatially independent locations were sampled with stainless steel cylinders (100 cm3) at two depths in the topsoil (1-5 cm and 16-20 cm). Sampleswere wet sieved into four aggregate size classes of <63 μm, 63-200 μm, 200-630 μm and 630-2000μm. Each aggregate size class was characterized by organic carbon (OC), total nitrogen (TN) andCaCO3 concentration. The chemical composition of the SOM of selected samples was characterized using solid-state 13C NMR spectroscopy. Wet sieving into aggregate size classes showed different trends along the chronosequence. Contradicting relation between CaCO3 and OC contribution to aggregate size classes display two different mechanisms on soil aggregate formation in young loess derived soils. CaCO3 influence daggregation predominantly in finer aggregate size classes, where the highest concentration and contribution was measured. SOM, on the other hand, played an important role on formation oflarge macro-aggregates after organic manure application in year 4. Furthermore, the loss of totalOC after year 12 was connected with the loss of OC contributing to the largest aggregate size class. Our findings reveal that SOM and CaCO3 role on stabilizing aggregates is not equally distributedand is aggregate size class dependent.


EPrint Type:Conference paper, poster, etc.
Type of presentation:Paper
Keywords:soil, soil organic matter
Agrovoc keywords:
Language
Value
URI
English
soil organic matter
http://aims.fao.org/aos/agrovoc/c_35657
Subjects: Soil > Soil quality
Research affiliation: Switzerland > FiBL - Research Institute of Organic Agriculture Switzerland > Soil > Soil quality
DOI:10.5194/egusphere-egu2020-13644
Deposited By: Forschungsinstitut für biologischen Landbau, FiBL
ID Code:39177
Deposited On:05 Feb 2021 11:57
Last Modified:05 Feb 2021 11:57
Document Language:English
Status:Published
Refereed:Peer-reviewed and accepted

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