Abstract:
This study aimed to evaluate the effectiveness of microbial agents in decomposing organic residues under different tillage practices in southern Ukraine from 2016 to 2020. Conducted at the Institute of Climate-Smart Agriculture, the research focused on dark-chestnut soil in a rainfed crop rotation involving winter wheat, grain sorghum, spring barley, sunflower, and a fallow field. Two factors were examined: microbial preparations and tillage (ploughing vs. ploughless). The Ecostern preparation, containing various bacterial strains and Trichoderma fungi, significantly accelerated winter wheat straw decomposition, achieving 45.9%-63.6% degradation within 90 days, a 31.4% increase over the control. The preparation Organic Balance, comprising Bacillus subtilis and other bacterial strains, maximised barley straw degradation at 80.1%. Sunflower residue mineralisation increased by 48.0%-55.5% with microbial treatments. These preparations also enhanced soil humus content by 0.06%-0.09%. The improved soil nutrient regime led to sorghum yield increases of 12.8%-45.3%, varying with tillage method. Spring barley yielded a maximum of 2.25 t/ha under ploughing with Organic Balance. Sunflower seed yields rose by 0.1-0.22 t/ha with ploughing. The accelerated organic matter transformation boosted soil biological activity, contributing to ecological sustainability. Ammonifying and nitrifying microorganism counts were highest with Ecostern and Organic Balance under shallow ploughless tillage, ranging from 19.82-25.87 and 7.31-12.76 CFU, respectively. Overall, the microbial preparations improved the soil’s nutrient regime, resulting in significant increases in crop yields
