The decomposition of organic matter influences CO
2 flux in peat soils. However, determination of the flux from the decomposition process is usually over-estimated because the total CO
2 flux calculation includes root respiration. We clarified this issue addressing the following aims: (i) to study the relation of oil palm root distribution in peat soils to the flux and (ii) to estimate the relative contribution of root respiration and peat decomposition to the total CO
2 flux. The study was conducted between January and June 2012. In the research area, three transects were established perpendicular to drainage channels, where nine14-year-old oil palm trees were selected and used as observation sites. Eight closed chambers were established as observation points at each site. We measured CO
2 flux at each point using an Infra Red Gas Analyzer (IRGA). Root and peat samples were collected from each observation point to measure root density and analyze peat chemical properties. Our results showed that the pH
H2O and nutrient content of P, K, Ca and Mg in the peat soils significantly increased of CO
2 flux. Oil palm roots at depths of 0–15 and 15–30 cm nearest the tree showed the highest density, while root densities gradually decreased with increasing distance from the tree. CO
2 flux in the peat soils nearest to the tree were highest at 0.44 ± 0.23 mg CO
2 m
-2 sec
-1 (or 137.7 ± 73.4 t CO
2 ha
-1 yr
-1). CO
2 flux significantly decreased with increasing distance from the tree, showing the lowest value of 0.10 ± 0.04 mg CO
2 m
-2 sec
-1 (or 30.67 ± 12.4 t CO
2 ha
-1 yr
-1). We conclude that the CO
2 flux was derived from peat decomposition and root respiration. Using the integral equation approach, the relative contribution of root respiration and peat decomposition was 74 and 26%, respectively to the total CO
2 flux.
View full abstract