Impact of Management Practices on Methane Emissions from Paddy Grown on Mineral Soil over Peat in Central Hokkaido, Japan

Abstract

This study was carried out at Kita-mura near Bibai located in central Hokkaido, Japan, with the intention of investigating the effects of different agronomical managements on CH 4 emissions from paddy fields on mineral soil over peat under farmers' actual management conditions in the snowy temperate region. Four fields were studied, including two fields with twice drainage (D 1 -M and D 2 -M) and also a single-drainage field (D 3 -S) under annual single-cropping and a paddy-fallow-paddy crop rotation as their systems. The other field was under single cropping annual with continuous flooding (CF-R) in the pattern of soybean (upland crop)-fallow-paddy. The mineral-soil thickness of these soil-dressed peatland fields varied from 20 to 47 cm. The amount of crop residues leftover in the fields ranged from 277 to 751 g dry matter m −2 . Total CH 4 emissions ranged from 25.3 to 116 g CH 4 -C m −2 per growing season. There was a significant relationship between crop-residue carbon (C) and total CH 4 emissions during the rice-growing season. Methane fluxes from paddy soils had a strong interaction between readily available C source for methanogens and anaerobic conditions created by water management. Despite the differences in water regime and soil type, the average values of straw's efficiency on CH 4 production in this study were significantly higher than those of southern Japan and statistically identical with central Hokkaido. Our results suggest that the environmental conditions of central Hokkaido in association with crop-residue management had a significant influence on CH 4 emission from paddy fields on mineral soil over peat. Rotation soybean (upland)-to-paddy followed by drainage-twice practices also largely reduces CH 4 emission. However, mineral-soil dressing on peat could have a significant impact on suppression of CH 4 emissions from beneath the peat reservoir.

Carbon Sequestration and Contribution of CO2, CH4 and N2O Fluxes to Global Warming Potential from Paddy-Fallow Fields on Mineral Soil Beneath Peat in Central Hokkaido, Japan

“…Over the growing period, water management influenced CO 2 and CH 4 emissions, although this depended on the drainage length [71]. These studies also indicate that the effects of straw addition on CH 4 emissions are sturdily dependent on management (water management that promotes aerobic conditions during drainage) and climatic conditions, as reported in our previous study [34]. It can also be attributed, however, to the delay in reducing N 2 O to N 2 by denitrification [57].…”

“…The cumulative CH4 emissions from paddy fields ranged from 75.5 to 116 g C m −2 during the rice growing season (Table 3a) (this cumulative CH4 emission data was published in Naser et al [34]. During the growing season, there was no significant variation in the CH4 fluxes, whereas in the winter-fallow season it varied significantly (p < 0.01), although the CH4 fluxes were very small during the winter-fallow period or appeared to be uptaken (0.119 to −0.019 g C m −2 ).…”

Drainage intensity in paddy rice fields : nitrogen flows, salinity, rice yield and greenhouse gas emissions

“…Estimated CH 4 emissions (0-0.8 kg ha −1 ) were low compared with those reported in other studies [56,57]. One probable explanation for the low CH 4 emissions was that the groundwater level was below the soil surface on all measurement occasions in our study.…”

Scaling Mechanization and Profitability in Maize Cultivation through Innovative Maize Planters along with Agroforestry Approach: Sustainable and Climate Smart Approach to Diversify Rice Based Cereal Systems in Various Regions

“…Growing rice in rotation with soybean and planting hybrid cultivars, drainage twice may result in reduced CH 4 emissions. However, mineral-soil dressing on peat could have a significant impact on suppression of CH 4 emissions from beneath the peat reservoir [52,53]. The study suggests that adoption of rice-rice-rape (Brassica napus L.) cropping system would be beneficial for greenhouse gas emission mitigation and as good cropping pattern in double rice cropped regions [54].…”