Application of two contrasting rice-residue-based biochars triggered gaseous loss of nitrogen under denitrification-favoring conditions: A short-term study based on acetylene inhibition technique

• Published in: Applied soil ecology : a section of Agriculture, ecosystems & environment ecosystems & environment, 2018-06, Vol.127, p.112-119
• Main Authors: Malghani, Saadatullah, Kim, Jinhyun, Lee, Seung-Hoon, Yoo, Ga-young, Kang, Hojeong
• Format: Article
• Language: English
• Subjects: Acetylene inhibition technique; Biochar; Denitrification; Denitrifying gene abundance; N2O
• ISSN: 0929-1393; 1873-0272
• DOI: 10.1016/j.apsoil.2018.03.011

•We recorded an increase in gaseous loss of N after application of rice base biochars.•The abundance of denitrifying genes nosZ and nirS were higher in biochar treatments.•Biochar addition to soil triggered rates of denitrification process.•Soils treated with alkaline biochar had the lowest N2O emissions. Denitrification is the key microbial process that leads to gaseous loss of soil nitrogen in agricultural lands. Most alarmingly, the dominant gas species could be N2O, which is a much stronger greenhouse gas than CO2. In addition to the primary role as tool for soil carbon sequestration, biochar has the potential to suppress N2O emissions. However, the mechanism for the suppression of N2O emissions by biochar remains elusive. To address this, we performed a short-term incubation experiment targeting the impact of two contrasting biochars on gaseous loss of soil N under denitrification-favoring conditions including high load of NO3− (100 µg N/g soil), anoxia and high moisture content (70% WFPS). The acetylene inhibition technique was adopted to differentiate N losses as N2 and N2O. Two biochars produced from rice chaff (600 °C, pH > 10, C:N 70) or rice husk (300 °C, pH