Comparison of indirect nitrous oxide emission through lysimeter drainage between an Andosol upland field and a Fluvisol paddy field

Abstract

Indirect emission of nitrous oxide (N 2 O) due to nitrogen (N) leaching and runoff from agricultural soils is a major source of atmospheric N 2 O. To evaluate the effect of agricultural land use in combination with soil type on indirect N 2 O emission through groundwater, we compared the indirect N 2 O emission between an upland field of Andosol and a paddy field of Fluvisol in a 1-year lysimeter experiment. We established a shallow groundwater table during the non-flooded fallow period in the Fluvisol paddy field to simulate moisture conditions in a lowland soil. Drainage was 795 mm yr À1 (median, n ¼ 6) in the Andosol upland field, versus 1583 mm yr À1 in the Fluvisol paddy field due to flooding during part of the year. The total leached nitrate in the Andosol upland field (4.24 g N m À2 yr À1) was comparable to that in the Fluvisol paddy field (5.57 g N m À2 yr À1). The total indirect N 2 O emission in the Fluvisol paddy field (88.6 mg N m À2 yr À1) was 55 times that in the Andosol upland field (1.62 mg N m À2 yr À1). The daily indirect N 2 O emission during the flooded period (0.239 mg N m À2 d À1) was comparable to that in the non-flooded period (0.156 mg N m À2 d À1) in the Fluvisol paddy field. The decrease in dissolved N 2 O concentration due to the flooding was offset by the increase in the drainage volume. The groundwater emission factors (EF 5g) were 0.0003 in the Andosol upland field and 0.0160 in the Fluvisol paddy field versus the IPCC default value of 0.0025. Although the lysimeters had some limitations to simulate actual field conditions, the results indicate that agricultural land use in combination with soil type can strongly affect indirect N 2 O emission through groundwater.

Changes in the Nitrogen Budget and Soil Nitrogen in a Field with Paddy–Upland Rotation with Different Histories of Manure Application

“…Because the lysimeter plots were surrounded by concrete frames, loss of flooding water via percolation through the levee (i.e., lateral seepage) did not occur. The rate of downward leaching (percolation) in this study (1 mm day −1 ) was set lower than those in other lysimeter experiments (e.g., 3.4 mm day −1 in [52] and 10 mm day −1 in [53]). Therefore, the amount of irrigation water in this study was also less than under actual field conditions.…”

Nitrous oxide fluxes and dissolved N gases (N2 and N2O) within riparian zones along the agriculturally impacted San Joaquin River

“…With the shallower groundwater tables in 2011, N 2 O had a slower upward advection and molecular diffusion time between the groundwater-soil interface. Thus, the high groundwater levels likely have a greater impact on soil surface N 2 O fluxes by slowing upward diffusion von der Heide et al 2009;Minamikawa et al 2011). The estimated fluxes (Equation S1) from groundwater were less than 0.06 mg N 2 O m -2 d -1 (data not shown), which is very low compared to soil surface fluxes.…”

“…During diffusion through the saturated zone, N 2 O may be further reduced to N 2 , reducing the potential for N 2 O emissions from groundwater to the atmosphere. However, other studies have concluded that greater than 20 % of total N loss may be attributed to N 2 O emissions from shallow groundwater (Minamikawa et al 2011;Anderson et al 2014).…”

Spatial and temporal variations in nutrients in water and riverbed sediments at the mouths of rivers that enter Lake Hachiro, a shallow eutrophic lake in Japan

“…The concentration of dissolved N 2 O (N 2 O) and CH 4 (CH 4 ) in the stream water was measured by using a headspace technique based on the principle of vapor-liquid equilibrium (Minamikawa et al, 2011;Sawamoto et al, 2002). We collected 30 mL of stream water using a 60-mL syringe in triplicate, without degassing, and the rest of the syringe was filled with 30-mL of O 2 -free ultrapure N 2 gas obtained from a Tedlar bag.…”