Monitoring of indicators and bacterial succession in organic-amended technosols for the restoration of semiarid ecosystems

• Published in: The Science of the total environment Vol. 954; p. 176302
• Main Authors: Soria, Rocío, Ortega, Raúl, Valiente, Nicolás, Rodríguez-Berbel, Natalia, Lucas-Borja, Manuel Esteban, Miralles, Isabel
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.2024
• Subjects: Bacterial diversity; Environmental monitoring; Quarry restoration; Sewage sludge; Soil management; Vegetable compost; Vegetable compost; Bacterial diversity; Environmental monitoring; Sewage sludge; Quarry restoration; Soil management
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.176302

Restoration of mining sites is essential to ensure ecosystem services and biodiversity. One restoration strategy employed in arid and semi-arid zones is the use of organic amendments to establishment technosols. However, it is necessary to monitor the restoration progress in order to select appropriate amendments. This study monitored the effects of compost gardening, greenhouse horticulture and stabilized sewage sludge, and their blends. We focused on soil physical and chemical indicators and bacterial community structure and diversity during the 30 months after application. Organic amendments increased total organic carbon and nitrogen within six months, staying elevated compared to natural soils over 30 months. Electrical conductivity rose then stabilized, the pH slightly decreased but stayed alkaline, and water holding capacity improved in treated technosols. Bacterial diversity increased in amended technosols compared to control. Alpha diversity varied with treatment and time, peaking at 18 months. Technosols with plant compost showed reduced bacterial richness at 30 months, while those with sewage sludge and its mixtures maintained it. The bacterial community analysis showed significant differences among treatments and times, highlighting dominant phyla like Proteobacteria and Bacteroidetes. PCoA analysis showed clear separation of bacterial communities from treated, natural, and control soils, with notable differences between plant and sludge treatments. Soil variables such as TOC, TN, EC and water holding capacity explained more than 82 % of the variation in bacterial communities. Eighty-three indicator taxa were identified that explained the differences between the microbial communities of treated and untreated soils, highlighting the importance of taxa such as Pelagibacterium spp., Roseivirga spp. and Cellvibrio spp. in preserving soil health. In short, organic amendments improve soil properties and promote the diversity and stability of beneficial microbial communities in semi-arid mined soils, underlining their crucial role in the restoration and long-term maintenance of degraded soils. [Display omitted] •Treated soils showed progressive changes in TOC, TN and water capacity.•Organic amendments boost both bacterial diversity and community homogeneity.•Bacterial compositions of restored soils gradually converged towards natural soil.•Bacterial structure changed dynamically, showing an ecological succession process.•Nitribacter, Roseivirga and Cellvibrio indicator taxa increased in amended soils.