Type and quantity of biochar influenced soil microbial activity and carbon priming effect

Abstract

Biochar has shown much potential to be used as soil amendment and conditioner as well as an effective alternative to waste disposal. However, the effect of biochar on soil organic matter varies according to the type of feedstock. This study aimed to evaluate the influence of different types and rates of application of biochar on soil microbial activity and on soil carbon priming effect. The incubation experiment was set up as a completely randomized design in a 2 x 5 factorial scheme, with two types of biochar (coconut husk and orange bagasse) and five rates of application (0, 5, 10, 15 and 30 t ha-1), with three replications. Soil microbial activity was evaluated through the concentration of CO2 released from the soil during a period of 130 days. Carbon priming effect was determined based on the CO2 respired in the biochar treated soil and in the control soil. Both biochars increased the total oxidizable carbon in the soil when they were applied at 30 t ha-1, however, the orange bagasse biochar was more effective than the coconut biochar. Coconut biochar increased the cumulative soil microbial respiration at all rates of application during the incubation period, therefore, it contributed to a positive carbon priming effect and should be applied with caution to avoid excessive loss of carbon from the soil. Orange bagasse biochar had little influence on the cumulative CO2 emission, except at 15 t ha-1, which increased soil microbial activity.

A data synthesis on the biochar properties and implications for air, soil, and water quality in Brazil

“…The N 2 O flux data were all obtained under conditions where nitrogen fertilizer (ammonium nitrate or urea) was applied. For this data synthesis, information was obtained from several studies (Abbruzzini et al., 2019; Alho et al., 2012; Carvalho Junior et al., 2019; Grutzmacher et al., 2018; Matos et al., 2021; Petter et al., 2016; Rittl et al., 2015, 2018, 2021)…”

“…Meta-analysis has indicated that biochar application changes soil The N 2 O flux data were all obtained under conditions where nitrogen fertilizer (ammonium nitrate or urea) was applied. For this data synthesis, information was obtained from several studies (Abbruzzini et al, 2019;Alho et al, 2012;Carvalho Junior et al, 2019;Grutzmacher et al, 2018;Matos et al, 2021;Petter et al, 2016;Rittl et al, 2015Rittl et al, , 2018Rittl et al, , 2021 [Color figure can be viewed at wileyonlinelibrary.com] mal and stressful conditions (Exhibit 7). Such results, however, most studies in Brazil have been performed under short-term controlled conditions.…”