Comprehensive Review on Biostimulants for Sustainable Agriculture: Global Market Trends and Experimental Challenges

Abstract

Biostimulants are natural/synthetic compounds that stimulate plant metabolic processes without functioning as nutrients or pesticides rather than by supplying nutrients. Defined by the European Biostimulants Industry Council (EBIC, 2016) and classified under European Regulation (EU) 2019/1009, these products stimulate physiological and rhizospheric functions to improve nutrient use efficiency, abiotic stress tolerance, and crop quality. Distinct from biofertilizers, which provide nutrients through microbial transformations, biostimulants act primarily by modulating plant signaling, metabolism, and microbiome interactions. Major groups include enzyme-based formulations, beneficial microorganisms (e.g., arbuscular mycorrhizal fungi, plant growth-promoting rhizobacteria), humic substances, protein hydrolysates, amino acids, and plant or seaweed extracts. Their functions range from enhancing root architecture and nutrient acquisition to improving osmotic regulation and antioxidant responses under stress. In the context of climate variability, soil degradation, and the global drive for sustainable intensification, biostimulants offer opportunities to reduce reliance on synthetic fertilizers, lower environmental footprints, and support resilient food systems. Although their adoption is expanding globally, challenges remain in efficacy evaluation, regulatory harmonization, and product quality. The global biostimulants market, valued at USD 3.0 billion in 2022, is projected to reach USD 5.4 to 6.85 billion by 2027-2030 (CAGR,10-11%), with microbial products and liquid formulations driving growth. Europe dominates adoption, while Asia–Pacific shows strong momentum. India, though representing only 3% of global share, is among the fastest-growing markets (USD 79.2 million in 2022 to USD 189.7 million by 2030, CAGR,11.5%), led by acid-based products and expanding seaweed extract use. Despite fragmented regulation and variable product quality, biostimulants hold significant promise for sustainable agriculture and food security. This review emphasizes biostimulant categories, mechanisms, and their roles in sustainable agriculture, highlighting  market potential in addressing productivity and environmental challenges.