Drainage and land use impacts on changes in selected peat properties and peat degradation in West Kalimantan Province, Indonesia

G. Z. Anshari,J. Sugardjito,L. Arianie,R. W. Nusantara,M. Afifudin,A. Rafiastanto,E. Gusmayanti,M. Nuriman,R. Susana

doi:10.5194/bg-7-3403-2010

Abstract

Abstract. Degradation of tropical peats is a global concern due to large Carbon emission and loss of biodiversity. The degradation of tropical peats usually starts when the government drains and clears peat forests into open peats used for food crops, oil palm and industrial timber plantations. Major properties of tropical peat forests are high in Water Contents (WC), Loss on Ignition (LOI) and Total Organic Carbon (TOC), and low in peat pH, Dry Bulk Density (DBD), and Total Nitrogen (TN). In this study, we investigated impacts of drainage and land use change on these properties. We collected peat samples from peat forests, logged over peat forest, industrial timber plantation, community agriculture, and oil palms. We used independent t-tests and oneway ANOVA to analyze mean differences of the research variables. We found that peat pH, DBD, and TN tend to increase. A significant decrease of C/N ratio in oil palm and agriculture sites importantly denotes a high rate of peat decompositions. Water contents, LOI, and TOC are relatively constants. We suggest that changes in pH, DBD, TN and atomic C/N ratio are important indicators for assessing tropical peat degradation. We infer that land use change from tropical peat forests into cleared and drained peats used for intensive timber harvesting, oil palms and industrial timber plantations in Indonesia has greatly degraded major ecological function of tropical peats as Carbon storage.

Highlights

Land use change and tropical peat degradation are commonly discussed from a perspective of Carbon emission (Page et al, 2004; Hooijer et al, 2010; Miettinen and Liew, 2010)
Most studies in tropical peats were based on remotely sensed data (Jaenicke et al, 2008), and general models of Carbon emissions associated with land use change and peat degradation (Page et al, 2004)
We summarized results of independent t-tests for acrotelm (0–100 cm) versus catotelm (>100 cm), and inland versus coastal peats in Table 7a and b

Summary

Introduction

Land use change and tropical peat degradation are commonly discussed from a perspective of Carbon emission (Page et al, 2004; Hooijer et al, 2010; Miettinen and Liew, 2010). Most studies in tropical peats were based on remotely sensed data (Jaenicke et al, 2008), and general models of Carbon emissions associated with land use change and peat degradation (Page et al, 2004). A study focusing on direct measurements of peat properties associated with drainage and land use changes is not common. We aim to discuss impacts of drainage and land uses on selected peat properties and peat degradation in West Kalimantan Province, Indonesia. We suggest important indicators of peat properties that could be used to indicate tropical peat degradation due to drainage and land use change. We believe that global climate change leading to more

Objectives

Methods

Results