Agroecological desert truffle cultivation promotes soil conservation and functionality in semi-arid Mediterranean areas

Soil degradation driven by agricultural intensification and land abandonment represents a major challenge in dryland regions worldwide, where soils with low organic matter and structural stability are highly vulnerable to erosion, nutrient depletion and loss of biological functionality. The cultivation of desert truffles ( Terfezia claveryi Chatin), involving an ectendomycorrhizal symbiosis with Helianthemum almeriense Pau and relying on low input agroecological management, has been proposed as a sustainable alternative for soil conservation. However, its effects on integrated physicochemical and biological soil properties and microbial community structure and function remain poorly understood. An assessment was conducted using soil samples from six desert truffle plantations and five nearby uncultivated plots across multiple locations, soil types and plantation ages. T. claveryi cultivation significantly improved soil physical structure, particularly in the topsoil, enhancing water infiltration and aggregate stability by 156% and 45%, respectively. Cultivated soils also exhibited higher fertility, with organic carbon and total nitrogen increasing by 32% and 30%, respectively. Soil enzymatic activity was enhanced, with β-glucosidase and alkaline phosphatase activities increasing by 90% and 53%, respectively. Soil respiration during winter and spring increased by 37% and 76%, respectively. Despite these changes, the core microbiome showed >90% overlap between plantation and uncultivated soils. Bacterial functional profiles were enriched in nitrogen-cycling and anaerobic processes in plantations, while fungal communities shifted from predominantly saprotrophic to symbiotrophic and ectomycorrhizal guilds. These findings support desert truffle cultivation as a sustainable strategy for improving soil conservation in semiarid lands, highlighting its potential as a nature-based approach combining soil restoration with agricultural production.