title: Understanding the role of soil erosion on co2-c loss using (13)c isotopic signatures in abandoned Mediterranean agricultural land.
abstract: Understanding soil water erosion processes is essential to evaluate the redistribution of soil organic carbon (SOC) within a landscape and is fundamental to assess the role of soil erosion in the global carbon (C) budget. The main aim of this study was to estimate the C redistribution and losses using (13)C natural abundance. Carbon losses in soil sediment, dissolved organic carbon (DOC) and CO2 emission were determined. Four bounded parallel plots were installed on a 10% slope. In the upper part of the plots, C3soil was replaced with C4soil. The SOC and δ(13)C were measured after 145.2mm rainfall in the upper (2m far from C4strip), middle (4m far from C4strip) lower (6m far from C4strip) trams of the plot and in the sediments collected in the Gerlach collector at the lower part of the plot. A laboratory incubation experiment was performed to evaluate the CO2 emission rate of soils in each area. OC was mainly lost in the sediments as 2.08g(-)(2) of C was lost after 145.2mm rainfall. DOC losses were only 5.61% of off-site OC loss. Three months after the beginning of the experiment, 15.90% of SOC in the upper tram of the plot had a C4 origin. The C4-SOC content decreased along the 6m length of the plot, and in the sediments collected by the Gerlach collector. CO2 emission rate was high in the upper plot tram due to the high SOC content. The discrimination of CO2 in C3 and C4 portion permitted to increase our level of understanding on the stability of SOC and its resilience to decomposition. The transport of sediments along the plot increased SOC mineralization by 43%. Our study underlined the impact of rainfall in C losses in soil and water in abandoned Mediterranean agriculture fields and the consequent implications on the C balance.
authors.affiliation: Department of Scienze Agrarie e Forestali, University of Palermo, viale delle Scienze, ed.4, 90128 Palermo, Italy. Electronic address: agata.novara@unipa.it.
authors.forename: Agata
authors.initials: A
authors.lastname: Novara
authors.affiliation: Soil Physics and Land Management Group, Wageningen University, Droevendaalsesteeg 4, 6708PB Wageningen, The Netherlands. Electronic address: saskia.keesstra@wur.nl.
authors.forename: Saskia
authors.initials: S
authors.lastname: Keesstra
authors.affiliation: Soil Erosion and Degradation Research Group, Department of Geography, University of Valencia, Valencia, Spain. Electronic address: artemio.cerda@uv.es.
authors.forename: Artemio
authors.initials: A
authors.lastname: Cerdà
authors.affiliation: Environmental Management Centre, Mykolas Romeris University, Vilnius, Lithuania. Electronic address: paulo@mruni.eu.
authors.forename: Paulo
authors.initials: P
authors.lastname: Pereira
authors.affiliation: Department of Scienze Agrarie e Forestali, University of Palermo, viale delle Scienze, ed.4, 90128 Palermo, Italy.
authors.forename: Luciano
authors.initials: L
authors.lastname: Gristina
keywords: (13)C natural abundance; C(3)/C(4) soil; Semiarid agroecosystem; Water erosion