Nitrous oxide and carbon dioxide emissions from surface and subsurface drip irrigated tomato fields

Irrigation practices change the soil moisture in agricultural fields, and influence emissions of greenhouse gases. A two-year field study was conducted to assess carbon dioxide (CO 2 ) and nitrous oxide (N 2 O) emissions from surface and subsurface drip irrigated tomato (Solanum lycopersicum L.) fields on a loamy sand in southern Ontario. Surface and subsurface drip irrigation are common irrigation practices used by tomato growers for irrigation in southern Ontario. The N 2 O fluxes were generally ≤50 µg N 2 O-N m -2 h -1 , with mean cumulative emissions ranging between 352 ±83 mg N 2 O-N m -2 and 486±138 mg N2O-N m -2 . No significant difference in N 2 O emissions between the two drip irrigation practices was found in either study year. Mean CO 2 fluxes ranged from 22 to 160 mg CO 2 -C m 2 h -1 with cumulative fluxes between 188 ±17 g CO 2 -C m-2 and 306 g CO 2