Combined Fertilization with Filter Cake, Microbial Consortium, and Amino Acids Improves Peanut Performance Under Water Scarcity Conditions

Water deficit is a major abiotic constraint limiting peanut (Arachis hypogaea L.) production. This study evaluated the combined effects of filter cake, foliar application of an amino acid-based biostimulant, microbial consortium inoculation, on peanut growth, physiology, and yield under water scarcity conditions. Treatments were arranged in a split-plot design with four replicates, where filter cake (0 and 5 t ha−1) was assigned to main plots, amino acid application to subplots (0.25 and 0.50 L ha−1), and microbial consortium to sub-subplots (100 and 200 mL m−2). At 50 days after sowing, plant growth parameters, relative chlorophyll content, and aboveground biomass were assessed, while yield components and seed yield were determined at harvest. Results indicated that the combined treatment with 5 t ha−1 filter cake, 0.50 L ha−1 amino acids, and 200 mL m−2 microbial consortium, consistently produced the highest main stem length (increase of 40%), aboveground biomass accumulation (increase of 41%), number of matured pods per plant (increase of 38%), seed mass per plant (increase of 87%), and final seed yield (increase of 86%) compared to the lowest-input treatment (F0A0.25M100) under water-limited conditions. These findings indicate that the integrated fertilization can improve phenological, physiological, and yield responses and represents a sustainable approach to improve peanut resilience and productivity under water scarcity.