A Comparison of Greenhouse Gas Emissions from a Paddy Field Following Incorporation of Rice Straw and Straw-Based Biochar

Abstract

To evaluate the effects of straw-based biochar on greenhouse gas emissions from paddy fields, a field study was conducted on a typical paddy field in subtropical China to compare the greenhouse gas emissions induced by rice straw and straw-based biochar incorporation. The cumulative CH₄ emissions were 281–515 kg CH₄ ha⁻¹ for the straw incorporation treatments, which were 2.6–6.4 times higher than with the biochar treatments. The cumulative N₂O emissions were 75.7–135 g N₂O ha⁻¹, and there was no significant difference between treatments. The calculated global warming potentials (GWPs) were 7,055–12,906 kg CO₂-eq ha⁻¹ for straw incorporation treatments, while those for the biochar incorporation treatments were only 1,776–2,004 kg CO₂-eq ha⁻¹. When divided by yield, the yield-scaled GWPs were 1,127–2,081 kg CO₂-eq Mg⁻¹, which were 2.0–7.0 times higher than those of the biochar treatments. The GWPs and yield-scaled GWPs of the greenhouse gases from the paddy field with straw-based biochar incorporation were much lower than with straw incorporation, indicating that the conversion of straw to straw-based biochar can be an effective means of carbon sequestration in rice production and can even increase grain yields to some degree. However, the long-term effects of biochar incorporation in paddy fields need further study.

Authors Jianlin Shen and Hong Tang were contributed equally to this work.