Net greenhouse gas balance of fibre wood plantation on peat in Indonesia

Abstract

Tropical peatlands cycle and store large amounts of carbon in their soil and biomass1–5. Climate and land-use change alters greenhouse gas (GHG) fluxes of tropical peatlands, but the magnitude of these changes remains highly uncertain6–19. Here we measure net ecosystem exchanges of carbon dioxide, methane and soil nitrous oxide fluxes between October 2016 and May 2022 from Acacia crassicarpa plantation, degraded forest and intact forest within the same peat landscape, representing land-cover-change trajectories in Sumatra, Indonesia. This allows us to present a full plantation rotation GHG flux balance in a fibre wood plantation on peatland. We find that the Acacia plantation has lower GHG emissions than the degraded site with a similar average groundwater level (GWL), despite more intensive land use. The GHG emissions from the Acacia plantation over a full plantation rotation (35.2 ± 4.7 tCO2-eq ha−1 year−1, average ± standard deviation) were around two times higher than those from the intact forest (20.3 ± 3.7 tCO2-eq ha−1 year−1), but only half of the current Intergovernmental Panel on Climate Change (IPCC) Tier 1 emission factor (EF)20 for this land use. Our results can help to reduce the uncertainty in GHG emissions estimates, provide an estimate of the impact of land-use change on tropical peat and develop science-based peatland management practices as nature-based climate solutions.

Declines of peatland water table forces climate warming despite methane emission drawdown

“…The decline in the WT of pristine peatlands may result in so-called "off-site" GHG fluxes [43][44][45][46]50,51 due to increased nutrient (e.g., organic and mineral C and N compounds) losses along hydrological pathways and GHG emissions from drainage ditches. Other off-site GHG fluxes refer to peat extraction, biomass (e.g., feed or food products) harvest or manure or mineral fertilizer application on drained peatlands, i.e., inputs or outputs of C and N, which are associated with GHG fluxes elsewhere 17,25 .…”

“…Additional measurements of the GHG balance for (sub)tropical peatlands are therefore urgently needed to reduce uncertainties. Additionally, we were unable to consider the potential C loss through biomass removals in globally drained peatlands used for forestry, mainly because the multidecadal rotations involved in logging process makes estimating the C balance highly uncertain and problematic 17 . Reporting the mean annual biomass removals through forestry used peatlands could help to further constrain the GHG balance estimations.…”

“…This happened at a large scale during the last century, as approximately 11-13% of all pristine global peatlands were drained 9,15,21 for arable farming 22,23 , pasture land 24-due to drainage and conversion to managed land uses 3,32,33 . While the drainage of pristine peatlands has significantly slowed in temperate and boreal regions, accompanied with increased restoration efforts 19,31 , the opposite trend is occurring in (sub)tropical pristine peatlands, specifically in Southeast Asia 17,28,34 . Threats to both (sub)tropical and temperate peatlands are likely to increase in climate change scenarios, with mid-latitudes and subtropics expected to experience changes in both the amount and timing of precipitation, potentially causing further drops in water table (WT) levels and impacting the GHG balance of pristine peatlands in Europe 19,20 , Southeast Asia 16,17 and elsewhere 35 .…”

“…The overall GHG balance of pristine global peatlands is therefore assumed to be approximately neutral 12,13 . However, this balance is delicate, as changes in hydrology due to drainage, land use change, water extraction 3,14-18 or regional changes in climate 19,20 may result in the mobilization of peatland soil C and N stocks, thereby changing pristine peatlands from C sinks to strong C sources 3,[15][16][17][18][19] . This happened at a large scale during the last century, as approximately 11-13% of all pristine global peatlands were drained 9,15,21 for arable farming 22,23 , pasture land 24-due to drainage and conversion to managed land uses 3,32,33 .…”

Effect of Nano-Bubble Irrigation on the Yield and Greenhouse Gas Warming Potential of Greenhouse Tomatoes

“…GWP GHGs -Warming potential of total soil CO 2 (biomass is partially reintroduced into the field and released into the atmosphere as carbon dioxide [22]), N 2 O, and CH 4 emissions, kg/hm 2 , in CO 2 equivalent, where the combined greenhouse effect (GWP) caused by each kg of CH 4 and N 2 O on a 100-year scale is 25 and 298 times higher than that of CO 2 , respectively.…”