Biochar application in a tropical, agricultural region: A plot scale study in Tamil Nadu, India

A plot-scale evaluation of biochar application to agricultural soils was conducted in Tirunelveli, Tamil Nadu, India, to investigate the potential of biochar to improve soil fertility and moisture content. Biochar feedstocks need to be sustainably sourced: several locally available feedstocks (rice husk, cassia stems, palm leaves and sawdust) were analysed as proposed soil amendments so that no single biomass material is depleted to maintain biochar addition. The biochars from different biomass feedstock contained >20% C and were high in macro- and micronutrients. The results suggest that an application rate 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 from several locally available feedstocks were analysed as proposed soil amendments.
► All biochars contained >20% C and were high in macro- and micronutrients.
► The results suggest that application of 6.6 tonnes ha-1 cassia biochar initiated C-accumulation.
► This is reflected in an increase in OM and a net reduction in soil bulk density.