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| Titel |
Reduced tillage and cover crops as a strategy for mitigating atmospheric CO2 increase through soil organic carbon sequestration in dry Mediterranean agroecosystems. |
| VerfasserIn |
Maria Almagro, Noelia Garcia-Franco, Joris de Vente, Carolina Boix-Fayos, Elvira Díaz-Pereira, Maria Martínez-Mena |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250135604
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| Publikation (Nr.) |
 EGU/EGU2016-16490.pdf |
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| Zusammenfassung |
| The implementation of sustainable land management (SLM) practices in semiarid
Mediterranean agroecosystems can be beneficial to maintain or enhance levels of soil organic
carbon and mitigate current atmospheric CO2 increase. In this study, we assess the
effects of different tillage treatments (conventional tillage (CT), reduced tillage
(RT), reduced tillage combined with green manure (RTG), and no tillage (NT))
on soil CO2 efflux, aggregation and organic carbon stabilization in two semiarid
organic rainfed almond (Prunus dulcis Mill., var. Ferragnes) orchards located in SE
Spain
Soil CO2 efflux, temperature and moisture were measured monthly between May 2012
and December 2014 (site 1), and between February 2013 and December 2014 (site 2). In site
1, soil CO2 efflux rates were also measured immediately following winter and spring tillage
operations. Aboveground biomass inputs were estimated at the end of the growing season in
each tillage treatment. Soil samples (0-15 cm) were collected in the rows between the trees
(n=4) in October 2012. Four aggregate size classes were distinguished by sieving
(large and small macroaggregates, free microaggregates, and free silt plus clay
fraction), and the microaggregates occluded within macroaggregates (SMm) were
isolated.
Soil CO2efflux rates in all tillage treatments varied significantly during the year,
following changes during the autumn, winter and early spring, or changes in soil moisture
during late spring and summer. Repeated measures analyses of variance revealed that there
were no significant differences in soil CO2 efflux between tillage treatments throughout the
study period at both sites. Average annual values of C lost by soil respiration were slightly but
not significantly higher under RT and RTG treatments (492 g C-CO2 m−2 yr−1) than under
NT treatment (405 g C-CO2 m−2 yr−1) in site 1, while slightly but not significantly lower
values were observed under RT and RTG treatments (468 and 439 g C-CO2 m−2 yr−1,
respectively) than under CT treatment (399 g C-CO2 m−2 yr−1) in site 2. Tillage
operations had a rapid but short-lived effect on soil CO2 efflux rates, with no significant
influence on the annual soil CO2 emissions. The larger amounts of plant biomass
incorporated into soil annually in the reduced tillage treatments compared to the
conventional tillage treatment promoted soil aggregation and the physico-chemical
soil organic carbon stabilization while soil CO2 emissions did not significantly
increase. According to our results, reduced-tillage is strongly recommended as
a beneficial SLM strategy for mitigating atmospheric CO2 increase through soil
carbon sequestration and stabilization in semiarid Mediterranean agroecosystems. |
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