Abstract
Charcoal stocks were determined in a chronosequence of soils which have been converted to agricultural land use by slash-and-burn up to 100 years ago. With time, opposite to our assumptions, the charcoal chemical quality, as measured by molecular markers for pyrogenic carbon, did not change and charcoal stocks did not show a clear decrease. Our results indicate that charcoal may resist chemical degradation even when exposed to intense weathering in a tropical climate.
3. Conclusions
The biochars from different biomass feedstock contained >20% C and were high in macro- and micronutrients. In this study, biochar application of 6.6 metric tonnes ha−1 cassia biochar was enough to initiate C-accumulation, which is reflected in an increase in OM and a net reduction in soil bulk density. Biochar application rates >10 metric tonnes ha−1 a−1 are recommended for high mineral content tropical soils.