Carbon dioxide emission and peat hydrophobicity in tidal peatlands

Abstract

Peatland describes the typology of tidal and freshwater swamplands. Peatlands are affected by tidal activity; the water level fluctuation causes the peat to dry out and then get wet, which affects the soil’s water content and carbon emissions. Additionally, mineral enrichment from river overflows affects soil fertility and peat stability. Peat stability is importantly related to the peatland management for agriculture. Functional groups in the peat, such as carboxyl and hydroxyl, are volatile and easily transform, decomposing from CHO bonds into CO2 under aerobic conditions. The characteristics of functional groups can be changed from polar to non-polar at the organic colloid surface, leading to hydrophobicity. This study evaluated carbon dioxide emissions and peat hydrophobicity. The research was conducted by survey and field sampling on two differently managed plots of peatlands: a rubber-and-pineapple intercrop plot and a traditionally-managed rubber plot. Parameters measured were CO2 flux, groundwater levels, water content, and peat hydrophobicity. Peat hydrophobicity was assessed by analyzing certain functional groups using a Fourier-Transform Infrared (FTIR) spectrophotometer. The results showed that CO2 emissions were 21.78 ± 5.44 (mg ha-1yr-1) for the rubber-and-pineapple intercrop and 19.15 ± 5.18 (mg ha-1 yr-1) for the traditionally-managed rubber plot. Peat hydrophobicity for both plots decreased with increasing soil depth, indicating that peat on the surface layer (0–50 cm) is more vulnerable to drought and fires, especially if there is no water management.

Keywords

• functional groups of peat
• land use
• soil water content