Effect of soil tillage and nitrogen fertilizer management on methane emissions from irrigated rice fields in Central Java, Indonesia

Rice ( Oryza sativa L.) production in the future aims to increase productivity every year with high input technology, including irrigated rice. However, the practices of irrigated rice fields have a high methane (CH 4 ) production potential. Soil tillage could affect CH 4 emission conditions. Puddling and flooding through soil tillage create reduction conditions that promote CH 4 production by methanogenic bacteria. The objective was to determine the effect of soil tillage and N fertilizer management on CH 4 emissions from rice fields with heavy-textured soil. The field experiment was arranged in a split-plot design in which soil tillage was the main plot and consisted of maximum tillage and no-tillage. Nitrogen fertilizer management was the split plot and consisted of a control without N, prilled urea broadcasting, prilled urea deep placement, ammonium sulfate (AS) broadcasting, AS deep placement, and tablet urea deep placement. No-tillage could reduce CH 4 emissions by 15.58% compared with maximum tillage. However, grain yield for no-tillage was lower than for maximum tillage with 2.73 and 3.68 t ha -1 , respectively. The AS and tablet urea deep placement emitted lower CH 4 and grain yield was higher than with other N management practices. The CH 4 emissions for AS and tablet urea deep placement was 96 and 97 kg CH 4 ha -1 season -1 and grain yield was 3.79 and 4.25 t ha -1 , respectively. The application of fertilizers incorporated into the soil increased rice productivity and mitigated CH 4 emissions from rice fields.