Carbon Storage in Organic, Labile, and Mineral Forms across Irrigated Soils of the Beni Moussa Sub-Perimeter, Tadla Plain (Morocco)

Abstract

The objective of this study was to evaluate how different soil types —Calcimagnesic , Fersialitic, Cambisol, Hydromorphic, and Isohumic— influence carbon stocks and key physico-chemical properties in semi-arid irrigated agroecosystems of the Beni Moussa perimeter, Morocco. A total of 85 soil samples (0–20 cm depth) were collected during the 2022–2023 dry season and analyzed for physico-chemical characteristics as well as different carbon fractions. Multiple statistical approaches, including analysis of variance (ANOVA), correlation analysis, and principal component analysis (PCA), were applied to assess variations among soil types and identify the main controlling factors. PCA explained 39.7% of the variance, separating carbonate-rich soils from organic-rich soils. ANOVA revealed significant effects of soil type on SOCS, LCS, and SICS, confirming the strong role of pedological differences in carbon dynamics. Isohumic soils, rich in organic matter, stored the highest SOC (≈11.7 kg C m⁻²) and LC (≈1.2 kg C m⁻²), while Calcimagnesic and Cambisol soils, with high carbonate content, exhibited elevated SICS (~5.2 kg C m⁻²). Our results demonstrate that soil type is a determining factor for carbon stocks and fractions. It is therefore essential to adapt agricultural practices to specific soil properties to maximize carbon sequestration potential and promote sustainable management in semi-arid irrigated regions.