Aims: This study aimed to evaluate the effectiveness of the interaction between biochar and nano-silica at different levels to improve the properties of degraded calcareous saline soils and enhance their suitability for cultivation.
Methods: A field experiment was conducted during the 2024–2025 growing season at the Research Station, University of Basrah. The experimental design included twelve treatments resulting from the interaction of four levels of nano-silica (0, 200, 300, and 400 kg.ha-1) and three levels of biochar (0, 20, and 30 t.ha-1) prepared locally from wheat straw residues.
Findings: Statistical analysis revealed a significant decrease (P < 0.01) in soil solution salinity (EC) from 11.41 dS.m-1 to 3.96 dS.m-1, and a reduction in pH from 7.85 to 7.42 at the maximum interaction (WSBC3 + Si4). Toxic and soluble ions concentrations declined sharply, with sodium (Na+) decreasing by 43.9%, chloride (Cl-) by 55.7%, and bicarbonate (HCO-3) by 62.9%. Furthermore, the availability of macronutrients (N, P, K) increased by 145%, 168%, and 48% respectively, due to improved ionic balance and plant uptake.
Conclusion: The integration of nano-silica and biochar represents a sustainable strategy for reducing salinity and enhancing soil fertility. The study recommends adopting an intervention of 30 t.ha-1 biochar plus 400 kg.ha-1 nano-silica for the effective reclamation of saline soils