Soil chemical, biological and physical properties play important roles in soil quality and are related with increasing organic matter content, soil microbiological activity, plant nutrient content and availability. A new generation of soil amendments, containing specific soil microorganisms, are of great interest worldwide. Field experiments were carried out in 2018-2019 at the Institute of Agriculture, Lithuanian Research Centre for Agriculture and Forestry. The aim was to determine the impact of bio-products containing Trichoderma reesei, Acinetobacter calcoaceticus or Bacillus megaterium, and their mixtures on changes of soil organic carbon (SOC), soil respiration, and microbial biodiversity in loamy Cambisol. Under dry meteorological conditions, Trichoderma reesei, Acinetobacter calcoaceticus and Bacillus megaterium bio-products resulted an increase in SOC content, C/N ratio, humic to fulvic acid ratio, soil respiration, and microbial biodiversity. It is concluded that the use of a mixture of three microorganisms (Trichoderma reesei + Acinetobacter calcoaceticus + Bacillus megaterium) is the most promising bio-amendment under climate change. Future research is needed on different soil types and textures.
Keywords: microbial biodiversity; plant-growth-promoting fungi; plant-growth-promoting rhizobacteria; soil organic carbon.