Teresa Gómez de la Bárcena

Research Scientist

(+47) 405 56 025
teresa.barcena@nibio.no

Place
Ås O43

Visiting address
Oluf Thesens vei 43, 1433 Ås

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Abstract

Afforestation of agricultural land is widely promoted as a nature-based solution to enhance carbon (C) sequestration and mitigate atmospheric CO2 levels. However, the temporal dynamics of soil organic carbon (SOC) after afforestation, particularly in mineral soils, remain uncertain due to the complex interaction of biogeochemical processes and their spatial variability. We investigated changes in SOC sequestration over five decades of afforestation on former cropland by extending the chronosequence approach with three repeated soil inventories in oak (Quercus robur L.) and Norway spruce (Picea abies (L.) Karst.) stands. Aboveground biomass C stocks were also quantified to evaluate the contribution of SOC to post-agricultural ecosystem C stocks. Forest floor C stocks increased rapidly in the early years and stabilized after approximately three decades, with consistently higher accumulation under Norway spruce than oak. In contrast, mineral SOC stocks in 0-25 cm depth increased with forest age by 0.18 ± 0.06 Mg ha−1 yr−1 under oak and 0.44 ± 0.07 Mg ha−1 yr−1 under Norway spruce. These contrasting trends in forest floor and mineral soil indicated a shift in C source-sink strength over time and between species. After 50 years of afforestation, total ecosystem C stocks in afforested stands reached up to 75% of those in a 200-year-old forest, with most new C stored in biomass (84-86%), followed by mineral soil (10-11%) and forest floor (4-5%). Despite higher sequestration of new C in Norway spruce stands, the relative distribution across ecosystem compartments was similar between tree species.

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Abstract

Rapporten sammenfatter resultater fra prosjektet “Fangvekster som klimatiltak i norsk kornproduksjon” (CAPTURE), gjennomført i 2021−2025. Målet med prosjektet var å dokumentere klimaeffekten av fangvekster på kornarealer i Norge, samt å utvikle gode dyrkingsstrategier. Rapporten presenterer dokumentasjon på mengde og variasjon i fangveksters biomasseproduksjon, bidrag til karbonfangst og lagring, utslipp av lystgass og evne til å holde på nitrat i jorda, samt en syntese av dette som kunnskapsgrunnlag for å kunne vurdere klimaeffekten av fangvekster under norske forhold.