Soil respiration, N2O, and CH 4 emissions from an Andisol under conventional-tillage and no-tillage cultivation for 4 years
2014
Yonemura, Seiichiro | Nouchi, Isamu | Nishimura, Seiichi | Sakurai, Gen | Togami, Kazuki | Yagi, Kazuyuki
No-tillage (NT) management is a promising method to sequester soil C and mitigate global warming caused by agricultural activities. Here, we report 4 years of continuous soil respiration rates and weekly nitrous oxide (N₂O) and methane (CH₄) emissions in NT and conventional-tillage (CT) plots in a typical Japanese volcanic soil. Overall, the soil respiration, N₂O emission, and CH₄uptake decreased significantly in the NT plot. A difference in soil respiration and N₂O emission between the two plots began after the tillage treatment and the incorporation of crop residues and fertilizers, whereas the CH₄uptake did not vary significantly during the fallow period after the treatments. The N₂O emission was higher from the CT than from the NT plot during the fall. The overall lower CH₄uptake in the NT than in the CT plot likely resulted from a combination of decreased soil gas diffusivity and higher mineral N content at the soil surface. Higher soil respiration and N₂O emission occurred in the NT plot in the summer of 2003 and were plausibly caused by an increase in the soil moisture content that resulted from lower temperatures during July and August; the higher soil moisture must have accelerated the decomposition of organic matter accumulated in the topsoil. These results indicate that NT management is generally effective for the mitigation of the total GWP by reducing soil respiration and N₂O emission in temperate regions; however, NT management may increase rather than decrease these emissions when fields experience cool summers with frequent rainfall.
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