Storage of carbon in constructed technosols: in situ monitoring over a decade

• Published in: Geoderma Vol. 337; pp. 641 - 648
• Main Authors: Rees, Frédéric, Dagois, Robin, Derrien, Delphine, Fiorelli, Jean-Louis, Watteau, Françoise, Morel, Jean Louis, Schwartz, Christophe, Simonnot, Marie-Odile, Séré, Geoffroy
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2019; Elsevier
• Subjects: Derelict land; Environmental Engineering; Environmental Sciences; Soil carbon sequestration; Soil compaction; Technogenic materials; GWC; PS; Soil compaction; Technogenic materials; Derelict land; Soil carbon sequestration; TIS
• ISSN: 0016-7061; 1872-6259
• DOI: 10.1016/j.geoderma.2018.10.009

Artificial soils constructed from wastes and by-products have been considered as a sustainable option for land reclamation. In particular, they could contribute in a complementary manner to natural soils to global climate regulation by storing large quantities of carbon (C). However, the evolution of C stocks in such newly formed soils remains largely unknown. This work aimed at evaluating the dynamics of C in constructed Technosols, focusing on two experimental sites in Lorraine, France, where Technosols were constructed from thermally-treated industrial soil, papermill sludge and green waste compost, and planted with grasses. Soil samples were collected over 12 years, and stocks of C were calculated, taking into account the increase in soil bulk density and the associated decrease in soil thickness over the years. The evolution of the stocks of organic C was compared to the evolution reported for natural grassland soils from the same region and for other Technosols. Initial organic C stocks in the two constructed Technosols were 50% higher than in natural analog soils when calculated over 30 cm, and up to 5 times higher when calculated over 100 cm. Organic C stocks in the two Technosols decreased over the first three years, but increased during the following years, most likely due to the accumulation of plant-derived C. A similar evolution was observed in other planted Technosols. We conclude that Technosols constructed from an adequate set of parent materials can keep large amounts of organic C over time and sequester additional C under permanent plant cover. [Display omitted] •Organic C stocks of two Technosols were 30% to 50% higher than in natural soils.•C stocks decreased by 30% for the first three years, and then slowly increased.•A similar increase was observed with other Technosols under permanent plant cover.