Effects of Biochar Amendment on CO₂ Emissions from Paddy Fields under Water-Saving Irrigation

Int J Environ Res Public Health. 2018 Nov 18;15(11):2580. doi: 10.3390/ijerph15112580.

Abstract

The role of carbon pool of biochar as a method of long-term C sequestration in global warming mitigation is unclear. A two-year field study was conducted to investigate the seasonal variations of CO₂ emissions from water-saving irrigation paddy fields in response to biochar amendment and irrigation patterns. Three biochar treatments under water-saving irrigation and one biochar treatment under flooding irrigation were studied, and the application rates were 0, 20, 40, and 40 t ha-1 and labeled as CI + NB (controlled irrigation and none biochar added), CI + MB (controlled irrigation and medium biochar added), CI + HB (controlled irrigation and high biochar added), and FI + HB (flood irrigation and high biochar added), respectively. Results showed that biochar application at medium rates (20 t ha-1) decreased CO₂ emissions by 1.64⁻8.83% in rice paddy fields under water-saving irrigation, compared with the non-amendment treatment. However, the CO₂ emissions from paddy fields increased by 4.39⁻5.43% in the CI + HB treatment, compared with CI + NB. Furthermore, the mean CO₂ emissions from paddy fields under water-saving irrigation decreased by 2.22% compared with flood irrigation under the same amount of biochar application (40 t ha-1). Biochar amendment increased rice yield and water use efficiency by 9.35⁻36.30% and 15.1⁻42.5%, respectively, when combined with water-saving irrigation. The CO₂ emissions were reduced in the CI + MB treatment, which then increased rice yield. The CO₂ emissions from paddy fields were positively correlated with temperature. The highest value of the temperature sensitivity coefficient (Q10) was derived for the CI + MB treatment. The Q10 was higher under water-saving irrigation compared with flooding irrigation.

Keywords: CO2; Q10; biochar; paddy field; water-saving irrigation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Agricultural Irrigation*
  • Air Pollutants / analysis
  • Air Pollutants / chemistry
  • Carbon Dioxide / analysis
  • Carbon Dioxide / chemistry*
  • Carbon Sequestration
  • Charcoal / chemistry*
  • Conservation of Water Resources / methods*
  • Environmental Restoration and Remediation
  • Oryza*
  • Seasons
  • Soil / chemistry

Substances

  • Air Pollutants
  • Soil
  • biochar
  • Carbon Dioxide
  • Charcoal