Effects of magnetized ionized water and Bacillus subtilis on water and salt transport characteristics and ion composition in saline soil

Magnetized ionized water and Bacillus subtilis are essential for enhancing soil salinity leaching and improving soil structure. To explore the combined effects of magnetized ionized water and B. subtilis on water–salt transport in saline soil, a one-dimensional vertical infiltration experiment was conducted. This study evaluated the soil water and salt distributions, infiltration model parameters and composition of exchangeable base ions with magnetized ionized water (M) and nonmagnetized-ionized water, alongside varying amounts of B. subtilis [B₀ (0%), B₁ (1.5%), B₂ (3.0%), B₃ (4.5%), B₄ (6.0%)]. The results showed that magnetized ionized water increased the infiltration volume and wetting front depth. As the application amount of B. subtilis increased, the changes in these two indicators initially increased but then decreased. The sorptivity parameter (S) mirrored this trend, whereas the shape coefficient (α) showed the opposite pattern. Compared with the B₀ treatment, the MB₁ treatment increased the 0–20 cm soil water content by 14%, decreased the salt content by 13% and improved the desalination rate by 98%, with the efficiency increasing by 62%. Moreover, the total exchangeable base ions increased, with the highest (Ca²⁺+ Mg²⁺) and lowest Na⁺ contents observed under B₁. MB₁ notably enhanced infiltration and water–salt transport, demonstrating significant desalination effects.