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.

Straw, as organic material, contains macronutrients and a wide range of micronutrients. Properly treated straw can become a valuable source for soil improvement and crop nutrition needs. The field experiment was carried out at the Institute of Agriculture, Lithuanian Research Centre for Agriculture and Forestry, in 2014–2021 on Cambisol. On a shallow ploughless tillage background, eight treatments were investigated: chopped straw + ammonium nitrate (CSA), chopped straw + ammonium nitrate + NPK (CSA+F), chopped straw + microorganisms (CSM), chopped straw + microorganisms + NPK (CSM+F), straw removed, not fertilized (SR), straw removed, fertilized (SR+F), chopped straw, not fertilized (CS), chopped straw, fertilized (CS+F). We hypothesized that treatment of straw with microbiological products in combination with mineral NPK fertilizers is a more efficient technology than treatment/non-treatment of straw with ammonium nitrate, either with or without NPK fertilizers. The aim of this work was to investigate the aftereffects of seven years use of mineral NPK fertilizers and bioproducts containing soil bacteria and microscopic fungi (Bacillus megaterium, Acinetobacter calcoaceticus, and Trichoderma reesei) in combination with straw management on soil sustainability (soil C sources, soil water release characteristics, pore-size distribution, aggregate stability, crop yielding capability) and soil vitality (CO₂ exchange rate-NCER). It was revealed that NCER was highest in the treatment CSM+F (Bacillus megaterium, Acinetobacter calcoaceticus, and Trichoderma reesei + NPK). It was 32.95% higher than in CSA (chopped straw without fertilizers) and 45.34% higher than in CSA+F (chopped straw + ammonium nitrate + NPK). Bioproducts applied favored soil vitality in general by exhibiting higher soil microbiological activity. As a result, a healthy and more viable Cambisol produced a higher winter wheat grain yield.