2020 Volume 11 Issue 1 Pages 5-25
In this study, we assessed the effects of a traditional farming system on carbon dioxide (CO2) and methane (CH4) emission from soils and on carbon storage. This practice involved gathering fallen leaves from secondary deciduous broad-leaved farm forests and using them as organic material in rice paddies in a hilly and mountainous area in the eastern part of northern Kanto, Japan. We established a plot each in two farm forests, from which litter was removed or not removed, and two plots, in which the farm forest litter was used or not used during rice cultivation, in a rice paddy that was flooded during winter. We measured daily CO2 flux through soil respiration in the plots using the closed-chamber method. We also measured daily CH4 flux in the plots, in which organic material (rice straw instead of leaf litter) was used or not used during rice cultivation, in the rice paddy. Based on these data and approximated soil temperature, we estimated the annual CO2 flux through soil respiration and annual CH4 flux. The annual carbon (CO2 + CH4) flux measures indicated that the traditional farming system (farm forest with litter removal + paddy flooded during winter with litter application) produced lower carbon flux (7.48 Mg C ha-1 y-1; 95%CI: 7.38–7.56) from the soil than the unmanaged system (farm forest without litter removal + paddy flooded during winter without litter application; 9.21; 95%CI: 9.13–9.30). The greenhouse gas emission (CO2 + CH4) based on global warming potential of CH4 emission indicated that the traditional farming system produced lower flux (12.16 Mg C ha-1 y-1; 95%CI: 12.10–12.21) than the unmanaged system (15.71; 95%CI: 15.63–15.79). The carbon storage did not differ between the two farming systems only for one-year research period. These results suggest that the traditional farming system reduced the carbon and greenhouse gas emission from soils.
