Biological Indicators of Soil Quality under Different Tillage Systems in Retisol

Soil microorganism diversity has a close relation with soil function, and the changes in the composition of the soil microbial population can directly affect it. The aim of this study was to identify the bacterial community composition and determine the main soil chemical and physical properties formed by the different tillage systems. In the experiment, we analyzed the combination of three tillage systems and four organic fertilizers. Soil samples were taken from the two layers of the soil profile: the upper 0-10 cm and the lower 10-20 cm. The composition and diversity of soil bacterial communities were assessed by the sequencing of 16S rRNA genes. Results revealed that the highest biodiversity was found in the soil with shallow ploughless tillage and enriched with farmyard manure. Actinobacteria and Proteobacteria were the dominant bacterial species across all treatments. Their total abundance varied between 26% and 36% in the different analyzed agroecosystems. For the Dystric Bathygleyic Glossic Retisol, shallow ploughless tillage is the most suitable tillage system, as it creates favorable conditions for the accumulation of organic carbon in the soil under the Western Lithuania climate conditions.