Nitrous oxide fluxes from upland soils in central Hokkaido, Japan

作者：Mu Zhijian; Kimura Sonoko D; Toma Yo; Hatano Ryusuke^*

来源：Journal of Environmental Sciences, 2008, 20(11): 1312-1322.

• mineral N pool
• N(2)O flux
• soil
• upland cropping system

Nitrous oxide (N(2)O) fluxes from soils were measured using the closed chamber method during the snow-free seasons (middle April to early November), for three years, in a total of 11 upland crop fields in central Hokkaido, Japan. The annual mean N(2)O fluxes ranged from 2.95 to 164.17 mu gN/(m(2).h), with the lowest observed in a grassland and the highest in an onion field. The instantaneous N(2)O fluxes showed a large temporal variation with peak emissions generally occurring following fertilization and heavy rainfall events around harvesting in autumn. No clear common factor regulating instantaneous N(2)O fluxes was found at any of the study sites. Instead, instantaneous N(2)O fluxes at different sites were affected by different soil variables. The cumulative N(2)O emissions during the study period within each year varied from 0.15 to 7.05 kgN/hm(2) for different sites, which accounted for 0.33% to 5.09% of the applied fertilizer N. No obvious relationship was observed between cumulative N(2)O emission and applied fertilizer N rate (P > 0.4). However, the cumulative N(2)O emission was significantly correlated with gross mineralized N as estimated by CO(2) emissions from bare soils divided by C/N ratios of each soil, and with soil mineral N pool (i.e., the sum of gross mineralized N and fertilizer N) (P < 0.001).

• 出版日期2008
• 单位西南大学