Effect of chemical fertilizer form on N2O, NO and NO2 fluxes from Andisol field

N2O, NO and NO2 fluxes from an Andosol soil in Japan after fertilization were measured 6 times per day for 10 months from June 1997 to April 1998 with a fully automated flux monitoring system in lysimeters. Three nitrogen chemical fertilizers were applied to the soil–calcium nitrate (NI), controlled-release urea (CU), and controlled-release calcium nitrate (CN), and also no nitrogen fertilizer (NN). The total amount of nitrogen applied was 15 g N m−2 in the first and the second cultivation period of Chinese vegetable. In the first measuremnt period of 89 days, the total N2O emissions from NI, CN, CU, and NN were 18.4, 16.3, 48.7, and 9.60 mgN m−2, respectively. The total NO emissions from NI, CN, CU, and NN were 48.4, 33.7, 149, and 13.7 mgN m−2, respectively. In the second measurement period of 53 days, the total N2O emissions from NI, CN, and CU were 9.66, 7.23, and 20.6 mgN m−2, respectively. The total NO emissions from NI, CN, and CU were 24.7, 2.60 and 34.2 mgN m−2, respectively. The total N2O emission from CU was significantly higher than CN. In the third cultivation period, all plots were applied with 10 g N m−2 of ammonium phosphate (AP) and winter barley was cultivated. In the third measurement period of 155 days, the total N2O and NO emissions were 9.02 mgN m−2 and 10.2 mgN m−2, respectively. N2O and NO peaks were observed just after the fertilization for 30 days and 15 days, respectively. N2O, NO and NO2 fluxes for the year were estimated to be 38.6 ∼ 81.5, 48.2 ∼ 181, and −24.8 to −39.3 mgN m−2, respectively. NO2 was absorbed in all the plots, and a negative correlation was found between NO2 flux and the NO2 concentration just after the chamber closed. NO was absorbed in the winter period, and a negative correlation was found between NO flux and the NO concentration just after the chamber closed. A diurnal pattern was observed in N2O and NO fluxes in the summer, similar to air and soil temperature. We could find a negative relationship between flux ratio of NO-N to N2O-N and water-filled pore space (WFPS), and a positive relationship between NO-N and N2O-N fluxes and temperature. Q10 values were 3.1 for N2O and 8.7 for NO between 5∼30 °C.