| Researchers have highlighted the importance of providing soil quality in agricultural systems,
besides mitigating greenhouse gases (GHG) emissions to the atmosphere and increasing soil
carbon sequestration. Therefore, several studies have demonstrated the effectiveness of
biochar as a soil conditioner, both in relation to increased C sequestration and improvements
in soil chemical, physical and biological attributes, resulting in better conditions for plant
growth. The aim of this study was to assess the impact of applying biochar produced from
sugarcane straw to soils in relation to changes in soil chemical attributes and mitigation of
greenhouse gases emissions into the atmosphere. To do so, we conducted a laboratory
incubation under controlled environmental conditions (ie temperature and humidity) with and
without the application of filter cake and vinasse (ie organic residues from sugarcane
industry) and rates of biochar application (0, 10, 20 and 50 Mg ha-1). The fluxes of CO2,
N2O and CH4 of each incubation unity were measured periodically (in days 1, 2, 5, 9,
13, 16, 20, 24, 28, 30, 47, 60, 91, 105, 123, 130, 138 and 150). Each treatment
consisted of eight replicates with destructive samples evaluated at 30, 60, 90 and 150
days after incubation to characterize the chemical attributes of the incubated soil,
besides GHG (CO2, N2O and CH4) emissions. In general, there was an increase in
carbon dioxide (CO2) fluxes over time due to the application of filter cake and
vinasse and increasing dose of biochar. Regarding nitrous oxide (N2O) emissions,
there was an increase of 82.35% with the application of vinasse and filter cake
compared to the control treatment. However, different doses of biochar (10, 20 and 50
Mg ha-1) reduced N2O emissions by 29, 38.7 and 70.9%, respectively. The methane
(CH4) flux was negligible in all treatments. We observed improvements in soil
chemical attributes, such as higher pH, a substantial increase in the soil CEC, reduced
exchangeable Al3+ and higher available P regarding the condition of the original soil. |