Kazuyuki Inubushi, Oslan Jumadi, Yusminah Hala, Abd Muis, Alimuddin Ali, Muhiddin Palennari, Kazuyuki Yagi
The influences of chemical fertilizers and a nitrification inhibitor on greenhouse gas fluxes (N2O and CH4) in a corn field in Indonesia were investigated using a closed chamber. Plots received 45+45 kg-N ha-1 of nitrogen fertilizer by split applications of urea, a single application of controlled- release fertilizer (CRF-LP30) or urea+dicyandiamide (DCD; a nitrification inhibitor), and no nitrogen application (control). Cumulative amounts of N2O emitted from the field were 1.87, 1.70, 1.06, and 0.42 kg N2O-N ha-1 season-1 for the urea, CRF-LP30, urea+DCD, and control plots, respectively. The application of urea+DCD reduced the emission of N2O by 55.8% compared with urea. On the other hand, the soil acted as a sink for CH4 in the CRL-LP30, control, and urea+DCD plots with value of -0.09, -0.06 and - 0.06 kg CH 4-C ha-1 season-1, respectively. When the viability of AOB (ammonia-oxidizing bacteria) and NOB (nitrite- oxidizing bacteria) were monitored, AOB numbers were correlated with the N2O emission. These results suggest that 1) there is a potential for reducing emissions of N2O by applying DCD, and 2) corn fields treated with CRF or urea+DCD can act as a sink for CH4 in a tropical humid climate.
Graduate School of Science and Technology, Makassar State University, Makassar, South Sulawesi 90224, Indonesia; Department of Biology, Faculty of Mathematics and Natural Science, Makassar State University, Makassar, South Sulawesi 90224, Indonesia; National Institute for Agro-Environmental Science (NIAES), Tsukuba, Ibaraki 305-8604, Japan; Graduate School of Horticulture, Chiba University, Matsudo 271-8510, Japan
