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dc.contributor.authorStegarescu, Gheorghe
dc.contributor.authorEscuer-Gatius, Jordi
dc.contributor.authorSoosaar, Kaido
dc.contributor.authorKauer, Karin
dc.contributor.authorTõnutare, Tõnu
dc.contributor.authorAstover, Alar
dc.contributor.authorReintam, Endla
dc.description.abstractThe decomposition of fresh crop residues added to soil for agricultural purposes is complex. This is due to di erent factors that influence the decomposition process. In field conditions, the incorporation of crop residues into soil does not always have a positive e ect on aggregate stability. The aim of this study was to investigate the decomposition e ects of residues from two di erent cover crops (Brassica napus var. oleifera and Secale cereale) and one main crop (wheat straw) on soil aggregate stability. A 105-day incubation experiment was conducted in which crop residues were mixed with sandy loam soil at a rate of 6 g C kg􀀀1 of soil. During the incubation, there were five water additions. The decomposition e ects of organic matter on soil conditions during incubation were evaluated by determining the soil functional groups; carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) emissions; soil microbial biomass carbon (MBC); and water-stable aggregates (WSA). The functional groups of the plant residues and the soil were analyzed using Fourier transform infrared spectroscopy (FTIR) and a double exponential model was used to estimate the decomposition rates. The results show that the decomposition rate of fresh organic materials was correlated with the soil functional groups and the C/N ratio. Oilseed rape and rye, with lower C/N ratios than wheat straw residues, had faster decomposition rates and higher CO2 and N2O emissions than wheat straw. The CO2 and N2O flush at the start of the experiment corresponded to a decrease of soil aggregate stability (from Day 3 to Day 10 for CO2 and from Day 19 to Day 28 for N2O emissions), which was linked to higher decomposition rates of the labile fraction. The lower decomposition rates contributed to higher remaining C (carbon) and higher soil aggregate stability. The results also show that changes in the soil functional groups due to crop residue incorporation did not significantly influence aggregate stability. Soil moisture (SM) negatively influenced the aggregate stability and greenhouse gas emissions (GHG) in all treatments (oilseed rape, rye, wheat straw, and control). Irrespective of the water addition procedure, rye and wheat straw residues had a positive e ect on water-stable aggregates more frequently than oilseed rape during the incubation period. The results presented here may contribute to a better understanding of decomposition processes after the incorporation of fresh crop residues from cover crops. A future field study investigating the influence of incorporation rates of di erent crop residues on soil aggregate stability would be of great interest.eng
dc.description.sponsorshipThe research was funded by the European Union’s European Regional Development Fund (Estonian University of Life Sciences ASTRA project [2014-2020.4.01.16-0036] “Value-chain based bio-economy”) and the Horizon 2020 project iSQAPER [project number 635750].eng
dc.rightsCreative Commons Attribution 4.0 International (CC BY 4.0) ; openAccesseng
dc.rights© 2020 by the authors.eng
dc.subjectaggregate stabilityeng
dc.subjectcover cropseng
dc.subjectdecomposition rateseng
dc.subjectgreenhouse gas emissionseng
dc.subjectmicrobial biomasseng
dc.titleEffect of crop residue decomposition on soil aggregate stabilityeng
dc.contributor.departmentInstitute of Agricultural and Environmental Sciences. Estonian University of Life Scienceseng

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Creative Commons Attribution 4.0 International (CC BY 4.0) ; openAccess
Except where otherwise noted, this item's license is described as Creative Commons Attribution 4.0 International (CC BY 4.0) ; openAccess