Boosting Soil Nutrients, Carbon Storage, and Wheat Yield with Co-Compost Organic Fertilizers and Growth-Promoting Microorganisms in Typic Haplustept Soils

Purpose Intensive farming systems that rely on imbalanced agrochemicals lead to nutrient immobilization and unstable carbon pools. This study evaluated the efficacy of cocomposting organic fertilizers and plant growth-promoting microorganisms (PGPMs) in improving soil fertility, carbon storage, and wheat (Triticum aestivum L.) yield. Methods Eight treatments were tested, including a control (T0), four combinations of 50% NPK with 25% organic amendments (vermicompost (V) with farmyard manure (F), bone meal (B), poultry manure (P), or sewage sludge (S)), and three fully organic combinations (25% VFBP, VFBS, and VPBS). Soil properties (pH, EC (Electrical Conductivity), NPK (Nitrogen, Phosphorus, Potassium) availability, microbial biomass carbon/nitrogen, labile carbon, total nitrogen, and dehydrogenase activity) and wheat growth parameters (biological yield, grain yield, straw yield, and harvest index) were analysed. Results The 25% VFBP treatment improved nitrogen availability at later growth stages, whereas the 50% NPK + 25% V-F and V-S treatments maximized phosphorus and potassium availability at flowering. Microbial biomass carbon and nitrogen were highest in the 25% VPBS treatment during tillering. Fully organic treatments increased soil dehydrogenase activity. The 50% NPK + 25% V-F treatment produced the highest biological yield, whereas the PCA highlighted 25%-VFBP + MC, VFBS + MC, and VPBS + MC as key contributors to the improvement in soil fertility. Conclusion Cocomposting organic fertilizers with PGPMs significantly increased soil fertility, carbon fractions, and wheat yield in Typic Haplustept soils. These findings support the integration of organic amendments with reduced chemical fertilizers for sustainable wheat production.