Fig. 5. Soil respiration measured as CO2 evolution in 3 min (a) and microbial biomass carbon (b) in the different treatments. Fertilizer level had no significant influence on CO2 evolution, values were only determined for pots without plants, light brown parts of the bars show fraction arising from the decomposition of native soil organic matter. Microbial biomass carbon was also independent of fertilizer level but significantly influenced by soil type, type of amendment and presence of plants. Here, green bars show results in the presence of plants, dotted bars symbolize calcareous soil, plain bars sandy soil. Data are given with respective standard deviations. HTC: hydrochar, PC: pyrochar. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)