Rhizobacteria-based technologies may constitute a viable option for biological fertilization and crop protection. The effects of two microbial inoculants (1) PPS: Pseudomonas protegens, P. jessenii and Stenotrophomonas maltophilia biocontrol bacterium strains and (2) TPB: Trichoderma atroviride, Pseudomonas putida, and Bacillus subtilis fungi, bacteria biocontrol, and biofertilizer combinations were examined on potato (Solanum tuberosum L. var. Demon) in three consecutive years in irrigated organic conditions. The number of tubers showing symptoms of Streptomyces sp. and Rhizoctonia sp. was recorded. The severity of symptoms was evaluated based on the damaged tuber surface. There was a large annual variability in both the symptoms caused by soil-borne pathogens, and the effect of bio-inoculants. In the first and second year, with a stronger Rhizoctonia and Streptomyces spp. incidence, the bacterial and fungal combination of TPB inoculums with both the potential plant nutrition and biocontrol ability of the strains seemed to have a better efficiency to control the diseases. This tendency was not supported in the third year, and this may be attributed to the relatively high natural precipitation. Further studies are required to investigate the agronomic benefits of these inoculants and to tailor their application to the soil microbial characteristics and weather conditions.

Potato holds significant importance in human nutrition. However, climatic stress factors such as prolonged drought have increasingly challenged potato production in recent years. Various research efforts are underway to mitigate the adverse effects of abiotic stress in potato agrotechnology, including the use of soil inoculation with beneficial microorganisms. Despite the promising results reported in the literature, there is still limited knowledge about the appropriate technology and microbial strains for field application, particularly in organic potato production. Therefore, a 2-year study was conducted to evaluate the effects of Pseudomonas brassicacearum 3Re2-7, Trichoderma asperelloides A, Rhizophagus irregularis MUCL41833, and Paraburkholderia phytofirmans PsJN strains under two irrigation strategies (irrigated and rainfed) in an organic potato field, using two varieties. Concerning the effects of microbial inoculations, significant differences were observed only in plant stomatal conductance among all measured parameters: inoculation with T. asperelloides significantly decreased stomatal conductance in potato plants. For the other studied parameters (yield, incidence of tuber pathogens, starch and phosphorus content of tubers, and SPAD values), the effects of variety, irrigation, and year were more significant than those of inoculation, regardless of whether strains were applied alone or in combination. The lack of significant inoculation effects may be attributed to open-field environmental conditions, limitations of soil nutrient status, application methodology, and resilience of the rich microbial communities associated with organic agriculture.

Optimizing nutrient management in organic polytunnel production remains challenging due to the limited availability of field-based knowledge on the mineralization dynamics of organic fertilizers. At the same time, microalgae-based products such as Chlorella vulgaris have gained increasing attention in recent research, yet their interactions with nutrient supply intensity are not well understood. This study aimed to evaluate the effects of increasing nutrient supply intensities (34, 116, and 189 kg ha⁻¹ N from different organic sources), in combination with C. vulgaris foliar application, on the crop performance of kapia pepper and a subsequent leafy green crop under on-farm organic polytunnel conditions on soil with moderate organic matter content. Increasing production intensity did not result in significant improvements in pepper yield or vegetative biomass (p > 0.05), and no significant residual effects of nutrient supply were detected in the yield of the subsequent leafy green crop (p: 0.08–0.94). C. vulgaris treatment showed predominantly non-significant but positive trends in several parameters, but only in combination with high-intensity technology, while reducing the total pest damage of the thrips and stinkbug index up to 15.7% in most technology variations. These results indicate that the effects of C. vulgaris may be strongly context-dependent and confirm that increasing the intensity of nutrient supply may carry the risks of conventionalization of organic farming practices.