European Journal of Sustainable Agroecosystems

The issue of decreasing fertility of agricultural soils poses a major challenge for the global food security along with sustainable productivity of agriculture. The biochar-compost represents an innovative solution for soil health improvement as well as nutrient availability increase. The goal of the current research was to investigate the influence of biochar-compost on soil fertility parameters, microbial community structure and activity, as well as the productivity of soybean in field conditions. To fulfil this goal, two-year field experiment was carried out using randomized complete block design with four treatments: (i) control (no amendments), (ii) compost alone (15 t·ha⁻¹), (iii) biochar alone (10 t·ha⁻¹), and (iv) biochar-compost combination (10 t·ha⁻¹ biochar + 15 t·ha⁻¹ compost). Periodic sampling was conducted to determine critical growth stages and properties of soil, including physicochemical properties, nutrient availability, microbial biomass carbon and nitrogen, enzymatic activity parameters and microbial diversity indexes. Main parameters of productivity were evaluated to monitor the growth and development of plants such as plant height, area, number of nodules, chlorophyll content, and yield. The use of biochar-enhanced compost increased the amount of soil organic carbon by 28.7%, available nitrogen by 34.2%, available phosphorus by 41.5%, and available potassium by 19.8% compared to the untreated control. Both microbial biomass carbon and dehydrogenase activity increased by 45.3% and 38.6%, respectively. Enzyme activities (urease, phosphatase, β-glucosidase) increased significantly with the use of compost fertilization with biochar. The yield of soybean increased by 42.8% with the application of biochar-based compost, with an increase in all yield contributing characteristics. The study suggests that biochar-enriched compost increases soil fertility through increased carbon sequestration; increased microbial activity; and improved nutrient availability, which significantly improves sustainable soybean production, confirming that the application of biochar-based compost is a good alternative for regenerative agriculture and sustainable intensification.