Fahmuddin Agus, Etik Handayani, Meine van Noordwijk, Kamarudin Idris, Supiandi Sabiham
Root respiration and microbial decomposition release CO2 from peatland. Mixture between these two measurements causes an over-estimation of greenhouse gas contribution, because CO2 produced by the former is offset by atmospheric CO2 removal during photosynthesis. We separated the two components by measuring, from closed chambers, the CO2 emission from the rooted (R) and non-rooted (NR) zones of peatland planted to oil palm. Three pieces of roots were channelled through a 5 cm hole into each of the grounded part of the R chamber. Emitted CO2 was captured by 30-cm diameter and 30-cm tall PVC gas chambers, sampled using 10 ml syringes, and measured using gas chromatography. The measurements were conducted in Aceh, Sumatra in the early rainy season (Oct-Nov 2008). We found that CO2 emitted from the NR chambers was about 62% of that of the R chamber, indicating a significant contribution of the root in producing CO2. The average amount of emitted CO2 from these 1, 5 and 10 year oil palm soils ranged from 18 to 24 t/ha/yr. Capturing both the R and NR zones in CO2 emission measurement is advisable, but under limited resources, the NR zone should be prioritised.
Peat, root respiration, microbial decomposition, CO2 emissions
Paper presented at 19th World Congress of Soil Science, Soil Solutions for a Changing World. 1-6 August 2010. Brisbane. Australia. Published on DVD.