Biostimulants for Sustainable Agriculture: Enhancing Plant Growth and Stress Resilience

Global agriculture faces the dual challenge of increasing productivity to meet the growing demand for food, feed, biofuels, and plant-based biomaterials while coping with soil degradation, climate change, and environmental pollution. Biostimulants have emerged as an innovative and sustainable strategy to enhance plant growth, nutrient uptake, and yield, as well as to mitigate the adverse impacts of abiotic and biotic stresses. Numerous studies show that biostimulant application can prevent 15–50% of potential yield losses caused by stressful environmental conditions. This review classifies major groups of biostimulants and examines mechanisms of their plant growth-promoting action at molecular, biochemical, physiological, and rhizospheric levels. Special emphasis is placed on their role in improving plant tolerance to drought, salinity, cold, heat, metal(loid) toxicity, and pest or pathogen attack. Limitations and challenges, including inconsistent results, variability in product efficiency, and the efforts on standardized formulations and application methods are also discussed. Finally, future research directions are highlighted, focusing on optimizing biostimulant performance to enhance crop resilience, productivity, and environmental sustainability.