In a Laboratory Experiment with Growing Miscanthus Sacchariflorus Application of Biochar Reduces CO2 Flux from the Soil

The aim of the work was to assess CO2 emissions from the soil upon the application of several types of biochars. In a laboratory experiment, the effects of adding different biochars to the soil were studied. This biochars were recommended for different purposes based on their properties: soil melioration (from Amaranthus cruentus biomass) or carbon sequestration (from Betula sp. wood and Miscanthus sacchariflorus biomass). Soil respiration (in the absence of vegetative plants) and ecosystem respiration (in the presence of vegetative M. sacchariflorus individuals) were assessed. Addition of all types of biochars led to a decrease in CO2 emissions from the soil surface. The CO2 flux in the absence of living M. sacchariflorus plants in the vegetative vessels decreased to a similar extent when adding all types of biochars. However, in the presence of living M. sacchariflorus plants in the vegetation vessels, differences were found in the intensity of ecosystem respiration in the variants with different biochar varieties. In the presence of M. sacchariflorus the highest CO2 flux was observed with the application of biochar from A. cruentus, the lowest, with the application of biochar from Betula sp. Thus, firstly, the addition of biochar reduced the CO2 flux from the soil and, secondly, the presence of vegetative plants is a significant factor modifying the differences in respiratory activity between substrates with biochars of different origins.