N2O emission and CH4 uptake in arable fields managed under conventional and reduced tillage cropping systems in northern Japan

摘要: [1] Nitrous oxide (N2O) emission and methane (CH4) uptake were measured in an experimental long-term tillage field (Andosol) Hokkaido, northern Japan, to assess their contributions net global warming, associated with arable crop production. From May 2001 August 2002, the was cultivated winter wheat, adzuki bean, sugar beet, potato, cabbage, where total N applied 110, 40, 150, 60, 220 kg ha−1 yr−1, respectively. Under conventional (CT) cropping systems, basal fertilization plowing for residue incorporation had little effect on N2O fluxes, but vigorous observed when rotary harrowing used incorporating N-rich cabbage residues into soil summer. Also, high emissions occurred there heavy rainfall after a large amount of fertilizer been beet also thawing frozen snow wheat treatment. Despite differing flux patterns among crops, annual from each positively correlated as fertilizer. CT across all five mean factor (the percent ratio N2O-N emitted out fertilizer) 0.36%. reduced (RT) left ground over winter, quantities bean thawed. Therefore, under RT systems much greater than systems. The rates CH4 by soils less sensitive type, management practices, application rates, strongly influenced management. For fallow, treatments, (1.36 yr−1), which 20-year history intensive plowing, lower those (2.40 yr−1). Thus production improved soils, although they adversely affected