GREENHOUSE GAS (GHG) EMISSIONS IN RELATION TO WATER TABLE AND SOIL AMELIORATION FROM TROPICAL PEAT SOILS

摘要

Tropical peatlands could be a source of greenhouse gases (GHG) as they contain large amounts of soil carbon (C). In order to be suitable for cultivation, peatlands must be drained, limed and fertilised due to the excess water, acidic soil properties and low soil fertility. On the other hand, drainage and soil amelioration may influence GHG emissions. This study was conducted with the aim to understand the effect of water table depth and soil amelioration on GHG emissions on tropical peat soils. Peat soil columns from Central Kalimantan, Indonesia were used to estimate GHG emissions under different water tables and soil amelioration treatments. Twenty seven peat columns were arranged using a randomized block design with two factors; water table position at 15 cm, 35 cm and 55 cm from the soil surface, and secondly 3 different ameliorants: without ameliorant/control, biochar (2.5 tonnes ha~(-1)) + compost (2.5 t ha"1); steel slag (2.5 t ha"1) + compost (2.5 t ha"1). Each of the treatments was replicated three times. Carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) emissions from the peat soil columns were measured at weekly intervals for 92 days and analysed using gas chromatography in the Indonesian Agricultural Environment Research Institute (IAERI). Results showed that soil ameliorations influenced CO2 and N2Q emissions from the peat soil. As application of soil ameliorants tended to stimulate GHG emissions, amelioration of peat soils to enhance soil fertility should be more wisely considered due to the effect on GHG emissions. Estimated GHG emissions from the treatments were between 0.12-0.32 kg CO2-C column~(-1) 92 days~(-1). Water tables affected the C-stock and net CO2-C exchange in peat soil columns.