Intercontinental comparison of greenhouse gas emissions from irrigated rice fields under feasible water management practices: Brazil and Japan

Abstract

Flooded rice fields are a significant anthropogenic source of methane (CH 4) and nitrous oxide (N 2 O) from agriculture in Asia, Latin America, and the Caribbean regions. In this work, we comparatively assessed the potential of intermittent irrigation and continuous rice flooding for reducing soil CH 4 and N 2 O emissions, partial global warming potential (pGWP), and its yield-scaled version (YpGWP) in northwestern Japan and southern Brazil. Seasonal CH 4 emissions under continuous flooded soils were slight higher in Japan (738 ± 87 kg ha −1) than in Brazil (623 ± 197 kg ha −1), and they were probably related to the higher level of soil organic C and the longer period under flooding in the seedling transplanting system in the Japanese site. Intermittent irrigation had similar efficiency in decreasing soil CH 4 emissions in both study areas, with the maximum mitigation potential of 71% in northwestern Japan and of 62% in southern Brazil. No significant difference in seasonal soil N 2 O emissions (−0.17 ± 0.05 to −0.24 ± 0.06 kg N 2 O ha −1 in Japan and 0.32 ± 0.08-1.16 ± 0.40 kg ha −1 in Brazil) or rice yield (7328-8064 kg ha −1 in Japan and 9391-10,231 kg ha −1 in Brazil) between irrigation systems was observed in either area. The potential of intermittent irrigation for reducing pGWP was around three times higher than that of continuous flooding in both sites. Thus, a reduction by 47-63% and 62-80% in yield-scaled pGWP was observed in southern Brazil and northwestern Japan, respectively. Like the well-established labor-intensive rice transplanting systems used in Asia, the introduction of feasible irrigation suppression systems in mechanized direct seeding rice fields in southern Brazil and other countries of Latin America and the Caribbean region is an effective choice for reducing greenhouse gas emissions with no adverse impact on rice yield.

Emission of greenhouse gases and yield-scaled global warming potential of rice cultivars under permanent and intermittent irrigation

“…4b) crop seasons, respectively. A large contribution of CH 4 in GWP related to N 2 O was observed in several other works (Bayer et al 2015;Camargo et al 2018;Zschornack et al 2018). These results demonstrate the great importance of CH 4 emitted in rice fields and the need to add mitigating measures for the emission of the gas.…”

“…These results are similar to those ones observed when Moterle et al (2013) evaluated permanent irrigation application (381.90 kg CH 4 .ha -1 ) and intermittent irrigation (313.5 kg CH 4 .ha -1 ). Studying different water management, Camargo et al (2018) had results that ranged from 237 (two intermittency in the rice cycle) to 623 (permanent irrigation) kg CH 4 .ha -1 , while Zschornack et al (2018) verified variation of CH 4 between 250.9 and 671.5 kg CH 4 .ha -1 . Furthermore, Bayer et al (2015) evaluated seven crop seasons of the rice and found average emission per crop of 367 kg CH 4 .ha -1 .…”

Effects of Water Management Practices on Methane Emissions and Rice Yields in East Asian Paddy Fields: A Regional-Scale Meta-Analysis

“…하지 만, 동일한 논임에도 불구하고 기후, 토양 조건 및 영농방식에 따라 배출되는 온실가스 배출 경향과 그 양이 달라지고 (Ahn et al, 2014;Liu et al, 2019a), 특히, 동아시아의 경우 장마 기후로 인한 CH 4 배출이 더욱 주목받고 있다 (Ito et al, 2022). 그동안 논물 관리에 관한 온실가스 완화 효과 및 쌀 생산량을 개별적으로 조사 및 분석한 연구는 상당부분 진행되어왔다 (Camargo et al, 2018;Bui et al, 2022)…”

Effects of Water Management and Rice Varieties on Greenhouse Gas Emissions in Central Japan

“…Some studies suggest that CH 4 fluxes differ among rice varieties [21,22]. Conversely, other studies suggest that CH 4 fluxes remain consistent among different crop varieties subjected to intermittent irrigation, while intermittent irrigation decreases CH 4 fluxes by 65% compared to flooding conditions [23]. Many studies have investigated the effects of fertilizer and water management on GHG emissions from rice fields [21][22][23].…”