Soil texture modulates microbial responses to irrigation: Implications for nutrient cycling in arid agroecosystem

Understanding how irrigation practices interact with soil texture and influence microbiomes and nutrient cycling is critical for improving soil fertility and ecosystem sustainability in arid regions. The aim of this two-year field study was to investigate the effects of different modes of irrigation, namely flood, combined, and mulched drip irrigation, on microbial ecological adaptations and nutrient sequestration in sandy, sandy loam, and loam soils. Mulched drip irrigation significantly enriched soil carbon (17.78 %–23.58 %), nitrogen (30.32 %–57.89 %), and phosphorus (23.07 %–26.59 %) compared to flood irrigation, with peak levels found in loam. The most pronounced increases in microbial α -diversity induced by mulched drip irrigation occurred in loam, exceeding those in sandy soils by 9.54 %. Microbial β -diversity was significantly affected by irrigation solely in sandy soils. Compared to loam, sandy soils exhibited a 4.70 % higher enrichment of copiotrophic taxa and a 13.46 % smaller reduction in oligotrophs under mulched drip irrigation. Mulched drip irrigation increased the complexity of the microbial network but decreased its stability. An elevated clay content enhanced complexity without reducing stability. Furthermore, mulched drip irrigation with loam maximally enriched carbon-assimilating microbes (69.11 %) and nitrogen-cycle genes (51.72 %), but minimally enriched metabolism-related bacterial functions (6.71 %). We revealed that irrigation, soil texture, and their interactions explained 55.59 %–68.96 % of the microbial assembly and functional variation. The results demonstrated that microbial assembly and functions driven by the irrigation-texture interactions serve as the key mediators of carbon, nitrogen, and phosphorus sequestration. Our findings extend insights into the microbiological driving mechanism of soil nutrient sequestration in arid agricultural ecosystem. • Mulched drip irrigation (W2) enriches C, N, and P in loam by 35.49 % over sandy soil. • W2 boosts microbial α -diversity and C-N cycle genes in loam (9.54 %–35.83 %) vs sand. • Sand with W2 maximally increases copiotrophic and metabolic taxa by 12.98 %–26.45 %. • Mulched drip irrigation raises microbial network complexity but reduces stability. • Microbes mediate C, N, and P sequestration under irrigation-texture interactions.