A sustainable strategy for saline agriculture: Integrating magnetoelectric brackish water and Bacillus subtilis to enhance water productivity and crop yield

Abstract

Soil salinization and water scarcity severely constrain agricultural productivity in arid regions, necessitating innovative approaches to manage multiple stresses. Despite their individual benefits, the combined effects of magnetoelectric water treatment and microbial amendments on saline-stressed crops remain unclear. This study investigated how magnetoelectric brackish water (MB) irrigation and Bacillus subtilis jointly regulate the rhizosphere water–salt environment and enhance pakchoi (Brassica campestris L.) productivity. A pot experiment tested two irrigation sources (brackish water, B; MB) combined with six B. subtilis rates (0, 5, 10, 20, 30, 40 g kg⁻¹). MB irrigation enhanced soil water retention by 10.9-56.3% and increased desalination efficiency over 30.0% in the 0-20 cm depth compared with conventional brackish water. The combined application of MB with 30 g kg⁻¹ B. subtilis optimized pakchoi growth dynamics through the Logistic model, increasing maximum plant height by 25.7% and maximum leaf area index by 26.0% relative to controls. This treatment enhanced photosynthetic capacity (P_nmax: 26.33 μmol m⁻² s⁻¹) and achieved highest yield (56.57 t ha⁻¹), representing a 53.7% increase over conventional brackish water. Mantel tests and regression analyses revealed that growth traits strongly correlated with yield (r = 0.61-0.85, P < 0.01), with optimal B. subtilis application at 37.9 g kg⁻¹ under MB irrigation predicted to achieve 54.64 t ha⁻¹. Comprehensive TOPSIS evaluation identified MB + 30 g kg⁻¹ B. subtilis as the optimal treatment (C = 0.984). These findings elucidate the physiological and agronomic basis of magnetoelectric water–microbe combined effects in saline agriculture, offering preliminary pot-scale evidence for sustainable crop management in arid regions.