Effects of organic and inorganic fertilizers on wheat growth, oxidative stress and soil microbial activity under water deficit conditions

Water scarcity significantly impacts global wheat production. This greenhouse study investigated the effects of inorganic (urea) and organic (vermicompost, well-decomposed farmyard manure) fertilizers on wheat (Triticum aestivum L. cv. Edessa) growth and soil microbial activity under two irrigation levels (100% and 50% water availability). Measured parameters included plant biomass, chlorophyll index (SPAD), relative water content (RWC), oxidative stress markers (H₂O₂, MDA), and soil microbial activity (CO₂ respiration, dehydrogenase activity). Under full irrigation, vermicompost increased plant dry weight (DW) by 14.1% and soil dehydrogenase activity (DHA) by 60.7% compared to the control. Water stress reduced DW by 36.1% and DHA by 72.3%, while increasing H₂O₂ and MDA levels. However, vermicompost and farmyard manure significantly mitigated these effects, improving DW by 20.7–29.3% and DHA by 124.8–177.0% (p<0.05). Vermicompost also reduced H₂O₂ by 20.4% and MDA by 37.8%, and improved RWC by 12.9% under stress. Organic fertilizers, particularly vermicompost and well-decomposed farmyard manure, significantly enhanced plant growth, photosynthetic capacity, and soil microbial activity under water deficit. These findings suggest that organic fertilization serves as a sustainable strategy for wheat production in water-limited regions, improving both crop productivity and soil health.