CO₂ emission in soil under eucalyptus cultivation with biochar application

Abstract

The use of biochar to fix carbon in the long term has become promising for reducing CO2 emissions, with eucalyptus bark being an excellent source of raw material for its production. This study aimed to evaluate the effect of applying eucalyptus bark biochar on soil CO2 emissions, in an area planted with eucalyptus. A randomized block design, with a 2 x 5 factorial scheme, was used, encompassing two pyrolysis temperatures (350 and 600 ºC) and five biochar doses (0, 0.625, 1.25, 2.5 and 5 Mg ha-1), with three replications, where the doses corresponded to 25 % of the dose used at planting. The soil CO₂ emissions, humidity and temperature were measured at 90, 97, 105, 112, 120 and 127 days of surface application of biochar. The 5 Mg ha-1 dose contributed to reduce the accumulated CO₂ emissions by 65 and 24 %, respectively for the pyrolysis temperatures of 350 and 600 ºC, when compared to the 0 Mg ha-1 dose, thus contributing to mitigate emissions and support agricultural and environmental sustainability. In order to reduce the CO2 flow, the period indicated for its application is when the soil temperature is higher and the soil humidity is lower.

KEYWORDS: Eucalyptus biochar, slow pyrolysis, forest residues, CO2 mitigation.