Figure 1
Left: The biochar starter pack included six pots (diameter = 5.5 cm; height = 5 cm; three pots/treatment), 15 bean seeds (Phaseolus vulgaris L. var. nanus), wood-based biochar (10 g), information about the background of the project, and instructions on how to conduct the experiment. Middle: “Kon-Tiki” biochar kiln. Right: CS experiment on a balcony. Photographs by the authors.
Figure 2
Overall effect of biochar on the Δ13C values of bean leaves. Means ± SD, n = 21–23. This is the mean value from all locations and replicates of the CS experiments. Higher values indicate less water stress.
Figure 3
Δ13C values of bean leaves at each location. Each location number (x axis) reflects one completed CS experiment. Mean value per treatment, n = 3 (target value).
Table 1
ANOVA table of F– and P– values of the effects of biochar and location and their interaction on Δ13C values of bean-leaves. D.f. = degrees of freedom.
| D.f. | F-value | P-value | |
|---|---|---|---|
| Biochar | 1 | 3.077 | 0.095 |
| Location | 11 | 11.999 | <0.001 |
| Biochar × Location | 11 | 3.262 | 0.011 |
Figure 4
Assessment of knowledge prior to project participation showing the relative frequency (%) of questions answered with yes (dark grey) and no (light grey) (n = 27). The bars from left to right indicate the following questions: Do you know the term “biochar”? Do you know why we are interested in using biochar? Did you ever hear about negative emission technologies – NETs? Do you know the term “carbon footprint”? Do you take actions to reduce your CO2 impact?