Integration of Mineral Fertilization and Microbial Inoculants to Enhance Wheat (Triticum aestivum L.) Yield and Soil Fertility in Clay Soil.

A field experiment was carried out during the 2020/2021 growing season at the Experimental Station Farm, Agricultural Research Center, Sirs El-Layan, El-Menoufia Governorate, Egypt, to evaluate the impact of biological inoculants in combination with different mineral NPK fertilizer levels (100%, 75%, and 50%) on the growth and productivity of wheat (Triticum aestivum L.). The biological treatments comprised a bacterial isolate (Bacillus safensis FO-36b), an actinomycete isolate (Streptomyces afghaniensis NR-114833.1), and their consortium. Results revealed that the combined inoculation of both microorganisms with 100% NPK fertilizer achieved the highest values for growth parameters, yield attributes, grain yield, and nutrient uptake compared with either mineral fertilization or single inoculations. Furthermore, no significant differences were detected between 50% and 75% NPK levels when combined with the microbial consortium, nor between the individual bacterial and actinomycete treatments. Soil fertility, indicated by available N, P, and K, was also enhanced under combined inoculation at different fertilizer levels compared with mineral fertilizers alone. These findings highlight the potential of integrated biofertilization strategies to improve wheat productivity and soil nutrient status while reducing chemical fertilizer inputs.