No-weeding suppressed methane emissions by Takanari and Koshihikari rice varieties under organic farming

作者：Jean Yves Dukuzumuremyi, Samuel Munyaka Kimani, Weiguo Cheng, Christian Nkurunziza, Margi Asih Maimunah, Eric CANTONA, Shuirong Tang, Shigeto Sudo, Yuka Sasaki, Hideki Murayama · 发表于：Journal of Agricultural Meteorology · 年份：2024 · DOI：10.2480/agrmet.d-23-00031 · 被引用次数：4 · 研究领域：Soil Carbon and Nitrogen Dynamics

To determine the difference in greenhouse gas emissions between two rice (Oryza sativa L.) varieties; Takanari (Tak) and Koshihikari (Kos), under organic rice cultivation with or without weeds management, a pot experiment was conducted at Tsuruoka, Yamagata, Japan. The Tak and Kos varieties were transplanted individually and interplanted as Tak+Kos, with the main treatments of weeding (w) and no-weeding (nw). Methane (CH4), nitrous oxide (N2O), and plant night respiration (CO2 emission) fluxes were measured once weekly or biweekly during the rice growth period. As the results, N2O fluxes were not detected but CH4 fluxes varied with the rice growth stage for all treatments. Compared with the Kos(w), Tak(w) and Tak+Kos(w) significantly decreased total seasonal CH4 emissions by 12.4% and 19.1%, respectively. This was attributed to higher rhizospheric CH4 oxidation and the offset of potential methanogenic activities because of the larger root biomass and a higher harvest index for both Tak(w) and Tak+Kos(w) compared with Kos(w). Conversely, Kos(nw) significantly reduced cumulative CH4 emissions by 31.7% and 48.6% compared with Tak(nw) and Tak+Kos(nw), respectively. This was ascribed to high rhizospheric CH4 oxidation promoted by the presence of significantly higher weed biomass for Kos(nw) at 65.0% and 44.0% compared with Tak(nw) and Tak+Kos(nw), respectively. On average, the no-weeding practice significantly decreased cumulative CH4 emissions by 50.5% compared with the weeding p...