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[en] 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 "1"3C natural abundance. Carbon losses in soil sediment, dissolved organic carbon (DOC) and CO_2 emission were determined. Four bounded parallel plots were installed on a 10% slope. In the upper part of the plots, C_3soil was replaced with C_4soil. The SOC and δ"1"3C were measured after 145.2 mm rainfall in the upper (2 m far from C_4strip), middle (4 m far from C_4strip) lower (6 m far from C_4strip) 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 CO_2 emission rate of soils in each area. OC was mainly lost in the sediments as 2.08 g"−"2 of C was lost after 145.2 mm 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 C_4 origin. The C_4-SOC content decreased along the 6 m length of the plot, and in the sediments collected by the Gerlach collector. CO_2 emission rate was high in the upper plot tram due to the high SOC content. The discrimination of CO_2 in C_3 and C_4 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. - Highlights: • The soil C isotopic difference is a useful tracer for erosion processes studies. • The main loss of Carbon was measured in soil sediment. • The transport increased strongly the mineralization of organic carbon.