Promising cyanobacterial species recommended as biofertilizers for agricultural soils

Aim. To identify the criteria and select cyanobacterial species that may be used as biofertilizers for agricultural soils. Methods. Specific methods of synthesis, logical analysis, and correlation of scientific results, comparison, systematization, explanation, and deduction were used in the work. Field studies were conducted on chornozem (typical, common, and leached) under various crops (sunflower, wheat, barley, corn, rape, and pea) in the central and southern regions of the Republic of Moldova from 2010 to 2025. Results of studies. The criteria for selecting bacteria to be applied as biofertilizers on agricultural lands, used for the cultivation of crop plants, were established as follows: dominance, spreading, high tolerance to environmental factors (without intermediate accommodation stages), a short generation time, and potential for industrial cultivation. The cyanobacteria recommended as biofertilizers for agricultural soils were identified, and their taxonomic position, from genus to species, was presented. The most representative genera of cyanobacteria recommended as biofertilizers for various soil types are as follows: Microcystis, Nostoc, Anabaena, Cylindrospermum, Tolypothrix, Calothrix, Oscillatoria, Phormidium, Lyngbya, Schizothrix, and Microcoleus. Also, 65 species of cyanobacteria, representatives of the dominant and globally widespread genera, recommended for use as biofertilizers, were determined. The optimal dose of cyanobacterial fertilizers (ranging from 5 to 258 kg/ha) and the form of their administration to ensure the sustainability of the health of soils and crops were established. Conclusions. Cyanobacteria are promising biofertilizers with proven impact on soil health and crop productivity. The study defines the criteria for selecting effective species and highlights the recommended genera and species for various soil types. Their application in the living form may support the fertility and sustainability of agroecosystems.