In‐Field Evaluation of <i>Triticum spelta</i> and <i>Triticum aestivum</i> Performance Under Contrasting Irrigation Regimes and Farming Systems: Impact on Yield, Grain Quality and Soil Microbiota

ABSTRACT Drought is a major abiotic stress affecting crop yields worldwide. Similarly, organic practices have been reported to enhance soil health and microbial diversity, influencing crop growth and yield. Given its drought tolerance, spelt ( Triticum spelta ) has been proposed as a resilient alternative to wheat ( Triticum aestivum ). Nevertheless, its agronomic and microbial responses under water‐limited conditions within different farming systems remain poorly understood. This study compares wheat and spelt under irrigated and rainfed environments using conventional and organic farming practices in the field. Spelt showed greater resilience to water‐limited conditions, maintaining yield, grain weight, and exhibiting higher antioxidant capacity under rainfed. Wheat yields dropped by 17% under rainfed but still remained 229% higher than spelt. Under organic farming, yields were 57%–85% and 77%–85% lower in spelt and wheat, linked to lower nitrogen availability. This provoked higher grain C/N ratios, indicating lower nutritional quality. Analysing belowground microbial ecosystem, farming practice was the primary factor explaining the dissimilarity of microbial community composition, with the irrigation regime playing a secondary role. Concretely, organic practices promoted the enrichment of soil bacterial microorganisms involved in nitrogen cycling and organic matter degradation, including members of Nitrosococcaceae SZB85, Thermomicrobiaceae, and Actinomycetospora ; however, this was not enough to increase nitrogen availability and promote plant yield. On the other hand, under rainfed, specifically in conventional soils, the potentially pathogenic species Ustilago maydis increased, while both wheat and spelt simultaneously recruited beneficial species for plant development, Chrysosporium pseudomerdarium . Similarly, in organic soils experiencing water‐limited conditions, an increase in beneficial microorganisms like Paraphoma radicina and Rhizopus arrhizus was also observed. Our findings highlighted the potential of spelt as a drought‐tolerant alternative in water‐limited regions while also revealing the limitations of organic farming practices for yield.