Sustainable Agro-Economic Development in Hyper-Arid Zones: Local Biochar Amendments as a Resource-Saving Strategy for Desert Wheat Cultivation

Abstract

An experimental study was conducted in the hyper-arid environment of El Oued city-Algeria, to evaluate the impact of various soil amendments (T0, T7) on soil moisture hydrodynamics, seed germination, and final crop productivity. The local core daytime microclimatic conditions during February featured solar radiation peaking at approximately 700 W/m² at solar noon, with ambient air temperatures fluctuating between a morning minimum of 10.5°C and a mid-afternoon maximum of 20.5°C. Hydrodynamic monitoring over a full 16-day cycle revealed that unamended native Saharan sand (T0) exhibited severe water-holding limitations, with volumetric moisture content collapsing precipitously from 80% to a critical minimum of 0% by Day 5. Conversely, carbonaceous biochar amendments (T3, T4) successfully established an internal capillary reservoir, sustaining elevated moisture configurations (=70%) through the initial desiccation phase. Biological monitoring revealed an intriguing agronomic paradox regarding early seedling establishment: the loose, macro-porous structure of raw control sand (T0) offered minimal physical impedance, securing the highest initial seed germination rate at 93%, followed closely by biochar blends T4 (90%) and T3 (89%), while treatment T2  heavily suppressed initial emergence to an absolute minimum of 50%. However, final structural harvest data collected at maturity demonstrated a complete inversion of these early vegetative trends. The unamended control sand (T0) produced heavily stunted ears capping at a meager 12.0 cm due to chronic late-stage moisture deficits and thermal stress. In contrast, the optimized structural composite amendment T6 yielded the absolute maximum final agronomic performance, achieving an optimal average ear length of 18.0 cm, followed closely by T5 (17.0 cm) and the biochar cohorts (16.0 cm). These findings explicitly demonstrate that while raw desert sand facilitates rapid initial sprouting, its severe evaporative desiccation neutralizes early growth advantages. Ultimately, the long-term hydro-thermal buffering and structural matrix modifications provided by advanced amendments—specifically T6, T5, and biochar configurations are the decisive factors required to secure optimal reproductive development and sustainable crop yields in hyper-arid agricultural zones.