N 2 O, CH 4 , and CO 2 Emissions from Continuous Flooded, Wet, and Flooded Converted to Wet Soils

Fluctuations in soil water content, either anthropogenic or natural, can remarkably influence the C and N pools in arable lands. The dynamics of C and N are directly related in regulation of greenhouse gases (GHGs) emissions. The present study was conducted to explore the effects of water regimes (continuous flooding, continuous wet, and flooding converted to wet) on soil GHGs emissions. Nitrous oxide (N 2 O) emissions from continuous flooding treatment were lower as compared with the continuous wet soil, but significantly ( p ≤ 0.01) enlarged in the flooding converted to wet soil treatment through increased mineral nitrogen. Methane (CH 4 ) emissions were significantly ( p ≤ 0.01) higher in the continuous flooding when compared with the wet soil conditions but substantially decreased in the flooding converted to wet soil treatment. Carbon dioxide (CO 2 ) emissions were significantly ( p ≤ 0.01) larger in the flooding converted to wet soil treatment as compared with the continuous flooding and wet soil treatments owing to increased mineralization and C contents. The results suggest that converting flooding to wet soil can substantially triggers the C and N pools and thus influences the GHGs emissions from soil.