Drip irrigation and integrated amendments drive soil–crop system improvements in calcareous soils

Soil salinity poses a major constraint to sustainable wheat production in arid and semi-arid regions like Egypt. This study assessed the impact of gypsum, sulfur, and humic acid amendments, under drip and furrow irrigation systems, on wheat productivity and soil physicochemical properties over two winter seasons (2022–2023 and 2023–2024) at the El Tor Pilot Area, South Sinai. A strip-split plot design was used, with irrigation methods as main plots and seven amendment combinations plus a control as subplots. Evaluations included crop traits, water consumption, water use efficiency (WUE), and soil properties across three depths (0–20, 20–40, 40–60 cm), analyzed via ANOVA, correlation heatmaps, and principal component analysis (PCA). Drip irrigation significantly reduced water use and improved WUE compared to furrow irrigation. The integrated application of gypsum, sulfur, and humic acid (G+S+H) consistently resulted in the highest grain yield, spike length, straw biomass, and 1000-grain weight. Correlation analysis revealed strong positive relationships between yield components and structural soil traits, while bulk density was negatively correlated with porosity and organic matter. PCA confirmed the clustering of G+S+H treatments under drip irrigation, highlighting enhancements in soil structure, nutrient availability, and salinity mitigation. The G+S+H combination effectively reduced soil pH from 8.55 to 8.06 and decreased TDS to 5333 mg·L⁻¹ , reflecting substantial improvements in chemical soil quality. These shifts enhance nutrient solubility and reduce ionic toxicity, supporting greater nutrient uptake potential. These results underscore the superiority of integrated soil–water strategies over single interventions in reclaiming saline soils. The findings offer practical, scalable solutions to improve soil quality, as demonstrated by significant reductions in bulk density and pH, alongside increased porosity and organic content, which collectively enhanced crop yield., water efficiency, and climate resilience in salt-affected agricultural zones. • Drip irrigation enhanced water use efficiency and reduced total water consumption. • Integrated G+S+H amendments improved yield and soil physicochemical properties. • Soil pH and salinity (TDS) significantly reduced under G+S+H treatment. • Bulk density declined while porosity and organic matter content increased. • PCA confirmed superior clustering of integrated treatments under drip irrigation.