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Article Dans Une Revue Communications in Soil Science and Plant Analysis Année : 2019

Carbon Turnover in a Sorghum-cultivated Semi-arid Mediterranean Soil Profile

Résumé

Organic carbon storage in soils is a key factor for agriculture sustainability and future climate control. Nevertheless, this issue has been insufficiently studied in the semi-arid context of northern Africa. Our aim was to quantify carbon dynamics in a Tunisian Calcaric Cambisol profile, using the natural C-13 labeling offered by the continuous C4 crop forage sorghum. Our results show that in the topsoil 0-30 cm, the amount of crop-derived carbon accounted for 20% of the cumulated input from crops after 12 years, and half of it was retrieved as organic matter with particule size < 50 mu m. Such values could be model-predicted with no particular adaptation to the specific calcareous environment using the RothC model. However, soils were additionally characterized by a very high subsoil organic carbon stock (170 t C ha(-1) between 30 and 140 cm), and we demonstrated that crop rooting highly contributed to this subsoil organic matter. Indeed, an unusually large proportion of new crop-derived carbon (one third) was found below the upper 30 cm. Our results show an increase in carbon content in the deep layers of this soil under semi-arid Mediterranean climate.
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Dates et versions

hal-02499533 , version 1 (05-03-2020)

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Jamel Jaouadi, Hamouda Aichi, Habib Ben Hassine, Abdessatar Hatira, Jérôme Balesdent. Carbon Turnover in a Sorghum-cultivated Semi-arid Mediterranean Soil Profile. Communications in Soil Science and Plant Analysis, 2019, 50 (19), pp.2457-2468. ⟨10.1080/00103624.2019.1667372⟩. ⟨hal-02499533⟩
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