Journal of Agronomy and Field Innovations

Background: Phaseolus vulgaris L. (common bean) is a globally important food legume that provides protein, dietary fiber, and micronutrients to millions of people, particularly in developing regions. Its productivity is frequently constrained by fungal, bacterial, and viral diseases and by copper deficiency, which impairs lignin biosynthesis, photosynthetic electron transport, and antioxidant enzyme function. Conventional copper fertilizers suffer from poor solubility, low bioavailability, and environmental accumulation, prompting interest in nanotechnology-based alternatives.
Objective: This study aimed to evaluate the effects of foliar and soil-applied nano-copper (CuO nanoparticles) on disease resistance, antioxidant defense, physiological performance, and yield of common bean under field conditions, relative to conventional copper sulfate fertilization.
Methods: A randomized complete block design with six treatments and three replications was conducted over two growing seasons. Treatments included an untreated control, conventional CuSO4, and nano-copper applied at 25, 50, and 100 mg L-1 via foliar spray, soil drenching, and combined application. Nano-copper particles were characterized by transmission electron microscopy, dynamic light scattering, X-ray diffraction, and Fourier-transform infrared spectroscopy. Disease incidence and severity, chlorophyll content, antioxidant enzyme activities (superoxide dismutase, catalase, peroxidase), malondialdehyde content, growth parameters, and yield attributes were recorded and analyzed using ANOVA followed by Tukey's HSD test (P < 0.05).
Results: Nano-copper treatments, particularly the combined foliar-soil application at 50 mg L-1, reduced disease severity index by up to 46% and significantly elevated superoxide dismutase, catalase, and peroxidase activities compared with the control and conventional copper. Chlorophyll content, photosynthetic rate, and relative water content improved substantially, while malondialdehyde accumulation declined, indicating reduced oxidative damage. Grain yield increased by 28-34% relative to the control and by 12-18% relative to conventional copper fertilization, accompanied by improved harvest index and nutrient-use efficiency.
Conclusion: Nano-copper fertilization enhances disease resistance, antioxidant defense, and productivity in common bean more effectively than conventional copper sources, offering a promising tool for precision and sustainable crop nutrient management pending further field-scale and environmental safety validation.