Increases in Greenhouse Gases Following the Use of Peatlands for Agricultural Areas

Abstract

Peatlands with very high C contents are generally considered a source of greenhouse gas (GHG) emissions. This research aimed to quantify the changes in peatland characteristics and GHG emission from the conversion of peatlands to agricultural areas. Height of water table, pH, electrical conductivity (EC), redox potential (Eh), organic carbon (OC), hot water-soluble C, total-N, the concentrations of NH4 +, and NO3 −, soluble-Al, soluble- Fe, and the emission of CH4, CO2 and N2O were quantified before and after land clearing of peats for agriculture. Results of study showed that pH, EC, OC contents, hot water-soluble-C, and total-N did not change after peatland clearing for agriculture. On the other hand, the concentrations of NH4 +, NO3 −, soluble-Al, soluble-Fe, redox potential and height of water table increased significantly after the peatland land clearing. Methane emissions from peatlands before peatland clearing were in the range of 0.13-0.22 mg C m−2 h−1 increased significantly to 0.14-0.31 mg C m−2 h−1 after the peatland clearing. The land clearing of peatlands for agricultural practices also caused increases in CO2 and NOx emissions by 85% and 76%, respectively. Changes in GGH emissions were not related to the changes in substrates quality of peats (OC contents, total-N and hot water- soluble-C). Results of the study indicate that increases in the GHG emission following the use of peatlands for agricultural areas are attributed to the changes in the peat characteristics.

Diversity in characteristics of tropical peatlands varying in land uses leads to differences in methane and carbon dioxide emissions

“…The decrease in carbohydrates and increase in lignin contents with changes in land use from uncultivated peatlands to cultivated peatlands are in agreement with the concept of changes in the chemical structure of organic C contained in peatlands with agricultural activities. Several agricultural activities in peatlands, such as drainage, fertilizing and liming, enhance the decomposition process of organic C contained in the peats, which in turn causes a decrease in organic C with structures that are easily decomposed, such as carbohydrates and results in the accumulation of organic C that is resistant to biodegradation such as lignin (Saidy et al 2018;Saidy et al 2020).…”

“…Hirano et al (2014) reported that CO2 emission of burned tropical peatlands observed through field measurement is in the range of 362-382 g C m -2 year -1 . Emissions of CO2 in tropical peatlands before and after land clearing for agriculture are 77-143 mg C m -2 h -1 or 674-1253 g C m -2 year -1 (Saidy et al 2020). Based on the monthly observation in the field, Wakhid et al (2017) found that CO2 emission from peat decomposition in a tropical peatland reached 1408 g C m −2 yr −1 .…”

Soil characteristics controlling nitrous oxide emissions of tropical peatlands

“…These pHs were in the pH range of tropical peats reported previously. For example, tropical peatlands with land-uses that vary from uncultivated to rice-cultivated peats and undrained to drained peats have a pH in the range of 3.34 to 5.33 [14,15]. Tropical-forested peatlands with varying organic carbon content had a pH range of 3.95-4.16 [16].…”

Translocation of tropical peat surface to deeper soil horizons under compaction controls carbon emissions in the absence of groundwater

“…The drainage of tropical peatlands brings about alterations in soil biogeo-physicochemical, thereby influencing the release of CO 2 , CH 4 , organic acids and organic particulates. Moreover, the rate of carbon loss is expected to be affected by climate change (2), particularly from the establishment of oil palm through the drainage and conventional slash-and-burn technique (3,4).…”