Multiple inter-tillage weeding effect on methane and nitrous oxide emissions pathways from rice paddy fields in Hokkaido, Japan

作者：Hiyori Namie, Kasane Shimada, Shuangshuang Zhao, Yo Toma, Munehide Ishiguro, Ryusuke Hatano · 发表于：Soil Science & Plant Nutrition · 年份：2025 · DOI：10.1080/00380768.2025.2457654 · 被引用次数：3 · 研究领域：Agriculture, Soil, Plant Science、Soil Carbon and Nitrogen Dynamics

Rice paddy fields are important sources of methane (CH4) and nitrous oxide (N2O). Generally, CH4 is emitted predominantly via rice, with smaller contributions from ebullition and diffusion, while CH4 oxidation varies by pathway. Research on N2O emissions remains ongoing. Multiple inter-tillage weeding (MIW), a traditional Japanese practice, is believed to enhance rice yield and improve anaerobic soil conditions. However, its effects on CH4 and N2O emission pathways remain unclear. This study aimed to quantify MIW’s impact on CH4 and N2O emissions through three pathways and MIW-mediated. Diffusive gas flux was determined by extracting net gas flux based on threshold values. Ebullitive gas flux was measured using a bubble-trapping method. Rice-mediated gas flux was calculated as the difference between total gas flux and the sum of diffusive and ebullitive gas fluxes. A chamber with disturbance functionality was developed to measure the MIW-mediated gas flux. Treatments of 0 (T0), 2 (T2), and 5 (T5) MIW practices were compared with conventional rice farming as a reference. Analysis of CH4 and N2O emission pathways during the MIW period revealed that gaseous CH4 influenced the ebullition and rice-mediated pathways, increasing the relative contribution of the diffusion pathway. High-frequency MIW (T5) enhanced the release of CH4-rich bubbles, temporarily reducing rice-mediated CH4 emissions. However, the contributed rate of MIW-mediated CH4 emission to the total CH4 emission durin...