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The effect of forest litter biochar on seed germination and early growth of two tree species (Trewia nudiflora and Lagerstroemia speciosa) was examined in a selected forest area of Nameri National ...

Mineralization of soil organic carbon has a significant impact on the atmospheric CO2 concentration. Application of organic amendments can affect the dynamics of carbon present in soil through the process of mineralization and immobilization. This study assessed the efficiency of biochar on soil carbon mineralization through respiration and the priming effect (positive or negative) after addition of the external carbon biomass in a controlled incubation experiment (90 days) at two different temperature regimes viz. 15 °C and 30 °C. A decrease in total CO2 respired was found with the addition of biochar in the soil where 6 t ha−1 of biochar treatment (T7) produced the lowest amount of CO2 for both the temperature regimes. The calculated half-life (t1/2) and rate constant (k) showed resistivity towards mineralization with increasing doses of biochar. Significantly negative priming effects were observed with addition of biochar in comparison to the control treatment at the end of the incubation period.

This study investigated the yields and the physicochemical properties of biochar from three different feedstocks viz., i) bioenergy byproducts (deoiled cakes of Jatropha carcus and Pongamia glabra), ii) lignocellulose biomass (Jatropha carcus seed cover), and iii) a noxious weed (Parthenium hysterophorus), obtained through slow pyrolysis at a heating rate of 40°Cmin-1 with a nitrogen flow 100mlmin-1 at a temperature range of 350-650°C. For successful utilization of biochar for C-sequestration, its ability to resist abiotic or biotic degradation was deduced from recalcitrance index R50 by using TG analysis. It was observed that the biochar produced at higher temperature had higher water holding capacity (WHC) and pH, suggesting its suitability as an amendment in soil with low water retention capacity; thus biochar may be designed to selectively improve soil chemical and physical properties by altering feedstocks and pyrolysis conditions. Biochar produced at 650°C had highest yield in the range of 28.52-39.9 wt.%.