Oslan Jumadi, Yusminah Hala, Kazuyuki Inubushi
Incubation and field experiments were conducted to determine emission and production of nitrous oxide (N2O) and responsible microorganisms in an upland acid soil of Indonesia. The results showed that N2O productions in the soil samples were affected by ammonium and urea amendments compared with control. N2O production reached the highest peak at the first week then decreased until 4 weeks incubation in the potato and tea soil samples. However, more N2O production was found in tea soil than potato soil. Pine forest soil produced N2O more at second week incubation than first week, then decreased until 4 weeks. These results further confirmed that the N2O emitted in the field, which was higher in tea garden than other fields. The both ammonium and nitrate contents in the tea soil were higher than potato and pine soils. The number of ammonium oxidizers in the pine and potato soils was not significantly different, but it was lower in the tea soil. Number of nitrite oxidizers was almost the same in the potato and tea soils, however it was lower in the pine soil. The number of denitrifiers was 1-3 orders magnitude higher in the tea soil than the potato and pine soils.
Graduate School of Science and Technology, Faculty of Horticulture, Chiba University, Matsudo, 271-8510, Japan; Department of Biology, Faculty of Mathematics and Natural Science, Makassar State University, Indonesia
