Improving nutrient use efficiency (NUE) is a major challenge in modern agriculture due to the environmental and economic drawbacks of excessive fertilizer use. Biostimulants—such as humic substances, seaweed extracts, protein hydrolysates, and microbial inoculants—are gaining attention as sustainable tools to enhance nutrient uptake and crop performance. This review synthesizes recent findings on the synergistic effects of biostimulants when integrated with conventional fertilizers. It addresses prevailing nutrient management challenges, categorizes major biostimulant types, elucidates their mechanisms of action, and evaluates factors influencing their effectiveness. These compounds act through diverse mechanisms, including stimulation of root growth, modulation of hormonal pathways, enhancement of rhizosphere microbial activity, and improved nutrient solubilization. Evidence from field studies indicates that co-application of biostimulants and fertilizers significantly improves absorption and assimilation of macro- and micronutrients, leading to higher yields, better nutritional quality, and increased stress resilience. However, variability in responses across crops and environments, coupled with the absence of standardized application protocols, limits widespread adoption. Key factors influencing biostimulant efficacy include crop genotype, growth stage, soil properties, climate conditions, and formulation type. Future research should focus on optimizing formulations, developing precision application strategies, and establishing regulatory frameworks to ensure safe and effective use. Overall, biostimulants represent a promising approach to complement traditional fertilization, reduce nutrient losses, and advance climate-smart, sustainable agriculture.

Biostimulants, nutrient uptake, fertilizer efficiency, plant growth, sustainable agriculture, humic acids, microbial inoculants

agronomy

Presentation: poster