Without transformative adaptation strategies, the impact of climate change is projected to reduce global crop yields and increase food insecurity, while rising greenhouse gas (GHG) emissions further exacerbate the crisis. While agriculture is a major contributor to climate change through unsustainable practices, it also offers significant opportunities to mitigate these emissions through the adoption of sustainable practices. This review examines climate-smart agriculture (CSA) as a key strategy for enhancing crop productivity, building climate resilience, and reducing GHG emissions, while emphasizing the need for strategic interventions to accelerate its large-scale implementation for improved food security. The analysis revealed that while nitrogen use efficiency (NUE) has improved in developed countries, the global NUE remains at 55.47%, emphasizing the need for precision nutrient management and integrated soil fertility strategies to enhance productivity and minimize environmental impacts. With 40% of the world’s agricultural land already degraded, sustainability alone is insufficient, necessitating a shift toward regenerative agricultural practices to restore degraded soil and water by improving soil health, enhancing biodiversity, and increasing carbon sequestration, thus ensuring long-term agricultural resilience. CSA practices, including precision agriculture, regenerative agriculture, biochar application, and agroforestry, improve soil health, enhance food security, and mitigate greenhouse gas emissions. However, result variability highlights the need for site-specific strategies to optimize benefits. Integrating multiple CSA practices enhances soil health and productivity more effectively than implementing a single practice alone. Widespread adoption faces socio-economic and technological barriers, requiring supportive policies, financial incentives, and capacity-building initiatives. By adopting climate-smart technologies, agriculture can transition toward sustainability, securing global food systems while addressing climate challenges.

The concept of plant biostimulants refers to substances or microorganisms used to improve the efficiency of nutrient uptake of a plant, improve stress tolerance, and improve overall quality. Extracts of microalgae are gaining increasing attention among biostimulants due to their rich bioactive content. Microalgae offer new opportunities in agriculture, wastewater treatment, pharmaceuticals, etc. These tiny organisms are known for their role in carbon dioxide sequestration, bioremediation, and the production of valuable compounds. Biostimulants act on plants through various mechanisms, promoting growth, nutrient mobilisation, and resistance to stress. The abundant amino acids and protein hydrolyzesate in microalgae improve nutrient absorption and act as osmoprotectants against stressors such as heavy metals and salt. The visual appearance of the potted plants plays a crucial role in determining their quality. Although research suggests a consumer preference for organically grown plants, the economic viability of organic ornamental plant production requires careful consideration of production costs and market demand. With the increasing demand for sustainable agricultural practices, the application of plant biostimulants, particularly those derived from microalgae, presents a promising opportunity to enhance productivity, improve soil health, address environmental issues, and overcome challenges posed by new regulations in the European Union related to the use of plant protection products.

Microalgae-based biostimulants may help reduce inputs in protected ornamental production, yet evidence across multiple growing seasons remains limited. We conducted a three-year polytunnel trial with six Pelargonium cultivars and applied two strains from the Mosonmagyaróvár Algal Culture Collection (MACC-612, Nostoc piscinale; MACC-922, Chlorella vulgaris). Using a factorial general linear model, we detected significant treatment effects on total dry mass, root mass, plant height, and root-collar diameter (all p < 0.001). Relative to the control, dry mass increased by 19.2% with MACC-612 and 33.1% with MACC-922, while root mass increased by >22% under both treatments. Root-collar diameter was strongly associated with overall plant size (R² = 0.89). Treatment × year interactions were not significant (p > 0.05), providing no statistical evidence of season-specific treatment effects within the three-year trial. Cultivars differed mainly in response magnitude rather than direction. Overall, microalgae applications improved biomass accumulation and root-linked structural traits associated with plant vigor under this production system.