Greenhouse Gas Emissions, Yield Scaled Index, and Carbon Stock as Affected by Soil Amendments in Cultivated Peat Soil

The increasing agricultural land conversion to non-agricultural land poses a challenge for providing national food demand. The use of peatlands for rice cultivation as part of extensification, as well as intensification, raises concerns about increased greenhouse gas (GHG) concentration in the atmosphere. Soil amendments can be applied to increase soil quality and enhance crop productivity. However, the application should be wisely used to avoid higher GHG emissions in cultivated peat soil. Therefore, this study aimed to observe the effect of soil ameliorants on yield scale of GHG emissions per unit grain yield (yield scale Global Warming Potential—GWP) and carbon stock in cultivated peatlands. The study was carried out on cultivated peatland in South Kalimantan. The treatments were control, dolomite, silicate fertilizer, rice straw, and animal manure. Each treatment was replicated three times. Gas samples of methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O) were collected three times during the rice growing season. The lowest yield scale GWP (ton CO2-e ton yield−1) was recorded at 3.15 with silicate fertilizer application, followed by 3.52; 4.22; 4.96, and 4.98 with application of dolomite, animal manure, rice straw, and control, respectively. Dolomite, silicate fertilizer, and animal manure amendment in paddy peat soil decreased seasonal GWP by 26, 18, and 16%, respectively. Carbon stock increased with the application of animal manure, rice straw, and dolomite compared to the control. Conclusively, it is recommended to apply silicate fertilizer and dolomite to reduce GWP and yield scaled GWP while adding animal manure to increase carbon stock from the rice-cultivated peat soil.