Water filled-pore space and soil temperature related to N2O fluxes from shallot cultivated in rainy and dry season

Agricultural soils managed with a large amount of fertilizer generate nitrous oxide (N2O). This study aims to observe the N2O flux rates from four organic matter treatments and examining soil water-filled pore space (WFPS) and soil temperature in rainy and dry seasons. The experimental sites took place on a silt loam soil with four organic matter treatments, i.e., 1). No organic matter (OM), 2). Chicken manure, 3). Cattle manure, and 4). Bio-compost. N2O fluxes were measured bi-weekly during the rainy season and weekly during the dry season. Soil WFPS and soil temperature were both determine at the same time. N2O fluxes from Shallot were significantly different between rainy and dry season (p<0.01), but not between treatments. It is ranged between 3.58 to 20.19 mg N2O m(-2) d(-1) on the rainy season and between 0.57 to 2.79 mg N2O m(-2) d(-1) on dry season. The linear regression showed that both soil WFPS and soil temperature only significantly relate to N2O fluxes in the rainy season. Soil WFPS >45% lead to high N2O fluxes and higher soil temperature. This finding showed that water is one of the vital inputs to maintain in order to mitigate N2O emission from agricultural soils, whether in upland or lowland.