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Rewetting Tropical Peatlands Reduced Net Greenhouse Gas Emissions in Riau Province, Indonesia. FORESTS 2022. [DOI: 10.3390/f13040505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Draining deforested tropical peat swamp forests (PSFs) converts greenhouse gas (GHG) sinks to sources and increases the likelihood of fire hazards. Rewetting deforested and drained PSFs before revegetation is expected to reverse this outcome. This study aims to quantify the GHG emissions of deforested PSFs that have been (a) reforested, (b) converted into oil palm, or (c) replanted with rubber. Before rewetting, heterotrophic soil respiration in reforested, oil palm, and rubber plantation areas were 48.91 ± 4.75 Mg CO2 ha−1 yr−1, 54.98 ± 1.53 Mg CO2 ha−1 yr−1, and 67.67 ± 2.13 Mg CO2 ha−1 yr−1, respectively. After rewetting, this decreased substantially by 21%, 36%, and 39%. Conversely, rewetting drained landscapes that used to be methane (CH4) sinks converted them into CH4 sources; almost twice as much methane was emitted after rewetting. Nitrous oxide (N2O) emissions tended to decrease; in nitrogen-rich rubber plantations, N2O emissions halved; in nitrogen-poor reforested areas, emissions reduced by up to a quarter after rewetting. Overall, rewetting reduced the net emissions up to 15.41 Mg CO2-eq ha−1 yr−1 (25%) in reforested, 18.36 Mg CO2-eq ha−1 yr−1 (18%) in oil palm, and 28.87 Mg CO2-eq ha−1 yr−1 (17%) in rubber plantation areas.
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Carbon Dynamics in Rewetted Tropical Peat Swamp Forests. CLIMATE 2022. [DOI: 10.3390/cli10030035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Degraded and drained peat swamp forests (PSFs) are major sources of carbon emissions in the forestry sector. Rewetting interventions aim to reduce carbon loss and to enhance the carbon stock. However, studies of rewetting interventions in tropical PSFs are still limited. This study examined the effect of rewetting interventions on carbon dynamics at a rewetted site and an undrained site. We measured aboveground carbon (AGC), belowground carbon (BGC), litterfall, heterotrophic components of soil respiration (Rh), methane emissions (CH4), and dissolved organic carbon (DOC) concentration at both sites. We found that the total carbon stock at the rewetted site was slightly lower than at the undrained site (1886.73 ± 87.69 and 2106.23 ± 214.33 Mg C ha−1, respectively). The soil organic carbon (SOC) was 1685 ± 61 Mg C ha−1 and 1912 ± 190 Mg C ha−1 at the rewetted and undrained sites, respectively, and the carbon from litterfall was 4.68 ± 0.30 and 3.92 ± 0.34 Mg C ha−1 year−1, respectively. The annual average Rh was 4.06 ± 0.02 Mg C ha−1 year−1 at the rewetted site and was 3.96 ± 0.16 Mg C ha−1 year−1 at the undrained site. In contrast, the annual average CH4 emissions were −0.0015 ± 0.00 Mg C ha−1 year−1 at the rewetted site and 0.056 ± 0.000 Mg C ha−1 year−1 at the undrained site. In the rewetted condition, carbon from litter may become stable over a longer period. Consequently, carbon loss and gain mainly depend on the magnitude of peat decomposition (Rh) and CH4 emissions.
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Comparing GHG Emissions from Drained Oil Palm and Recovering Tropical Peatland Forests in Malaysia. WATER 2021. [DOI: 10.3390/w13233372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
For agricultural purposes, the drainage and deforestation of Southeast Asian peatland resulted in high greenhouse gases’ (GHGs, e.g., CO2, N2O and CH4) emission. A peatland regenerating initiative, by rewetting and vegetation restoration, reflects evidence of subsequent forest recovery. In this study, we compared GHG emissions from three Malaysian tropical peatland systems under the following different land-use conditions: (i) drained oil palm plantation (OP), (ii) rewetting-restored forest (RF) and (iii) undrained natural forest (NF). Biweekly temporal measurements of CO2, CH4 and N2O fluxes were conducted using a closed-chamber method from July 2017 to December 2018, along with the continuous measurement of environmental variables and a one-time measurement of the soil physicochemical properties. The biweekly emission data were integrated to provide cumulative fluxes using the trapezoidal rule. Our results indicated that the changes in environmental conditions resulting from draining (OP) or rewetting historically drained peatland (RF) affected CH4 and N2O emissions more than CO2 emissions. The cumulative CH4 emission was significantly higher in the forested sites (RF and NF), which was linked to their significantly higher water table (WT) level (p < 0.05). Similarly, the high cumulative CO2 emission trends at the RF and OP sites indicated that the RF rewetting-restored peatland system continued to have high decomposition rates despite having a significantly higher WT than the OP (p < 0.05). The highest cumulative N2O emission at the drained-fertilized OP and rewetting-restored RF sites was linked to the available substrates for high decomposition (low C/N ratio) together with soil organic matter mineralization that provided inorganic nitrogen (N), enabling ideal conditions for microbial mediated N2O emissions. Overall, the measured peat properties did not vary significantly among the different land uses. However, the lower C/N ratio at the OP and the RF sites indicated higher decomposition rates in the drained and historically drained peat than the undrained natural peat (NF), which was associated with high cumulative CO2 and N2O emissions in our study.
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Rossita A, Nurrochmat DR, Boer R, Hein L, Riqqi A. Assessing the monetary value of ecosystem services provided by Gaung - Batang Tuaka Peat Hydrological Unit (KHG), Riau Province. Heliyon 2021; 7:e08208. [PMID: 34746469 PMCID: PMC8555274 DOI: 10.1016/j.heliyon.2021.e08208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 07/05/2021] [Accepted: 10/14/2021] [Indexed: 11/30/2022] Open
Abstract
Peatland plays a pivotal role in providing natural resource production and environmental services for human welfare. However, many studies have mentioned the impact of dryland cultivation in peatland on the shifting carbon balance in the ecosystem that clearly will alter the interaction of these two ecosystem services. The goal of this study, conducted under the framework of the System of Environmental-Economic Accounting (SEEA) framework, was to monetary value the ecosystem services (ES) of provisioning and carbon regulating services of the Gaung-Batang Tuaka Peat Hydrological Unit (KHG). We focused on KHG in response to Regulation No.57/2016, which highlights ecosystem boundary as a new basis for peatland management. Under the SEEA framework, ecosystem services become a benefit when utilized by ecosystem beneficiaries. In this case, provisioning services will be valued only for cultivated land, while carbon services calculated for the entire study area (global beneficiaries). Our study showed that the provisioning services and carbon services are under the trade-off condition, where the monetary value of provisioning services increased at a slower rate (0.50 million USD annually) than the monetary loss of the benefit of carbon services (5.28 million USD annually), greatly exceeded the monetary value of provisioning services. We highlight two main strategies to increase the monetary value of the KHG towards a synergy condition, namely increased value-added by reducing the productivity gap among ES beneficiaries and large-scale adoption of a profitable cultivation system with minimum peat disturbance. The main enablers required include financing access and incentives (e.g., reduce tax) and disincentives to allow for peat-adaptive commodities to compete with dryland commodities in the future market.
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Affiliation(s)
- Annuri Rossita
- Applied Climatology Study Program, the Graduate School of IPB University, Bogor, Indonesia.,Center for Climate Risk and Opportunity Management in South East Asia and Pacific (CCROM-SEAP), IPB University, Bogor, Indonesia
| | - Dodik Ridho Nurrochmat
- Department of Forest Management, Faculty of Forestry and Environment, IPB University, Bogor, 16680, Indonesia
| | - Rizaldi Boer
- Applied Climatology Study Program, the Graduate School of IPB University, Bogor, Indonesia.,Center for Climate Risk and Opportunity Management in South East Asia and Pacific (CCROM-SEAP), IPB University, Bogor, Indonesia
| | - Lars Hein
- Environmental Science Analysis Group, Wageningen University and Research, Wageningen, the Netherlands
| | - Akhmad Riqqi
- Faculty of Earth Science and Technology, Bandung Institute of Technology (ITB), Indonesia
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Geographic Setting and Groundwater Table Control Carbon Emission from Indonesian Peatland: A Meta-Analysis. FORESTS 2021. [DOI: 10.3390/f12070832] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Peat restoration is a key climate mitigation action for achieving Indonesia’s Nationally Determined Contribution (NDC) emission reduction target. The level of carbon reduction resulting from peat restoration is uncertain, owing in part to diverse methodologies and land covers. In this study, a meta-analysis was conducted to assess the impact of rewetting on reduction of total CO2 in soil and heterotrophic emissions at the country level. The tier 2 emission factor associated with the land cover category in Indonesia was also calculated. The analysis included a total of 32 studies with 112 observations (data points) for total CO2 emissions and 31 observations for heterotrophic emissions in Indonesia. The results show that the land cover category is not a significant predictor of heterotrophic and total soil emissions, but the highest observed soil emissions were found in the plantation forest. Using the random-effects model, our results suggest that an increase in the water table depth of 10 cm would result in an increase in total CO2 emissions of 2.7 Mg CO2 ha−1 year−1 and an increase in heterotrophic emissions of 2.3 Mg CO2 ha−1 year−1. Our findings show that managing water table depth in degraded peatlands in various land cover types is important to achieve Indonesia’s emission reduction target by 2030.
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The Use of Subsidence to Estimate Carbon Loss from Deforested and Drained Tropical Peatlands in Indonesia. FORESTS 2021. [DOI: 10.3390/f12060732] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Drainage is a major means of the conversion of tropical peat forests into agriculture. Accordingly, drained peat becomes a large source of carbon. However, the amount of carbon (C) loss from drained peats is not simply measured. The current C loss estimate is usually based on a single proxy of the groundwater table, spatially and temporarily dynamic. The relation between groundwater table and C emission is commonly not linear because of the complex natures of heterotrophic carbon emission. Peatland drainage or lowering groundwater table provides plenty of oxygen into the upper layer of peat above the water table, where microbial activity becomes active. Consequently, lowering the water table escalates subsidence that causes physical changes of organic matter (OM) and carbon emission due to microbial oxidation. This paper reviews peat bulk density (BD), total organic carbon (TOC) content, and subsidence rate of tropical peat forest and drained peat. Data of BD, TOC, and subsidence were derived from published and unpublished sources. We found that BD is generally higher in the top surface layer in drained peat than in the undrained peat. TOC values in both drained and undrained are lower in the top and higher in the bottom layer. To estimate carbon emission from the top layer (0–50 cm) in drained peats, we use BD value 0.12 to 0.15 g cm−3, TOC value of 50%, and a 60% conservatively oxidative correction factor. The average peat subsidence is 3.9 cm yr−1. The range of subsidence rate per year is between 2 and 6 cm, which results in estimated emission between 30 and 90 t CO2e ha−1 yr−1. This estimate is comparable to those of other studies and Tier 1 emission factor of the 2013 IPCC GHG Inventory on Wetlands. We argue that subsidence is a practical approach to estimate carbon emission from drained tropical peat is more applicable than the use of groundwater table.
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Prananto JA, Minasny B, Comeau LP, Rudiyanto R, Grace P. Drainage increases CO 2 and N 2 O emissions from tropical peat soils. GLOBAL CHANGE BIOLOGY 2020; 26:4583-4600. [PMID: 32391633 DOI: 10.1111/gcb.15147] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 04/20/2020] [Indexed: 06/11/2023]
Abstract
Tropical peatlands are vital ecosystems that play an important role in global carbon storage and cycles. Current estimates of greenhouse gases from these peatlands are uncertain as emissions vary with environmental conditions. This study provides the first comprehensive analysis of managed and natural tropical peatland GHG fluxes: heterotrophic (i.e. soil respiration without roots), total CO2 respiration rates, CH4 and N2 O fluxes. The study documents studies that measure GHG fluxes from the soil (n = 372) from various land uses, groundwater levels and environmental conditions. We found that total soil respiration was larger in managed peat ecosystems (median = 52.3 Mg CO2 ha-1 year-1 ) than in natural forest (median = 35.9 Mg CO2 ha-1 year-1 ). Groundwater level had a stronger effect on soil CO2 emission than land use. Every 100 mm drop of groundwater level caused an increase of 5.1 and 3.7 Mg CO2 ha-1 year-1 for plantation and cropping land use, respectively. Where groundwater is deep (≥0.5 m), heterotrophic respiration constituted 84% of the total emissions. N2 O emissions were significantly larger at deeper groundwater levels, where every drop in 100 mm of groundwater level resulted in an exponential emission increase (exp(0.7) kg N ha-1 year-1 ). Deeper groundwater levels induced high N2 O emissions, which constitute about 15% of total GHG emissions. CH4 emissions were large where groundwater is shallow; however, they were substantially smaller than other GHG emissions. When compared to temperate and boreal peatland soils, tropical peatlands had, on average, double the CO2 emissions. Surprisingly, the CO2 emission rates in tropical peatlands were in the same magnitude as tropical mineral soils. This comprehensive analysis provides a great understanding of the GHG dynamics within tropical peat soils that can be used as a guide for policymakers to create suitable programmes to manage the sustainability of peatlands effectively.
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Affiliation(s)
- Jeremy Aditya Prananto
- Sydney Institute of Agriculture, School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Budiman Minasny
- Sydney Institute of Agriculture, School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
| | | | - Rudiyanto Rudiyanto
- Program of Crop Science, Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, Kuala Nerus, Malaysia
| | - Peter Grace
- Centre for Agriculture and the Bioeconomy, Queensland University of Technology, Brisbane, Qld, Australia
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Lin S, Cheung YK, Xiao Y, Huang X. Can rain suppress smoldering peat fire? THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 727:138468. [PMID: 32334212 DOI: 10.1016/j.scitotenv.2020.138468] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 04/03/2020] [Accepted: 04/03/2020] [Indexed: 06/11/2023]
Abstract
Smoldering wildfire in peatlands contributes significantly to global carbon emissions and regional haze events. Smoldering fire in peatlands is one of the largest and most persistent fire phenomena on Earth. Here we assess the underlying mechanism of rain in suppressing the smoldering peat fire in the shallow soil layer up to 15 cm deep through laboratory experiments. We show that the minimum rainfall intensity to extinguish the peat fire is roughly 4 mm/h, so that the persistent light rain cannot suppress such smoldering wildfire. The required rain duration, ∆t (min), for extinguishing smoldering peat fire decreases with the rainfall intensities, I (mm/h), as log10∆t = - 1.15log10I + 3.3, and is much longer than that for extinguishing flaming wildfire. We also identify that the required rainfall depth for extinguishing peat fire gradually decreases with the rainfall intensity and approaches a minimum value of 13 mm under violent rain. As rainfall intensity increases, the carbon emission flux from peat fire decreases. Therefore, we conclude that the short-term violent rain is most effective for suppressing the persistent smoldering peat fire. This research helps evaluate the impact of weather on the development of peat fire and improve the prediction of carbon emissions from peat fire with the use of regional weather models.
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Affiliation(s)
- Shaorun Lin
- Research Centre for Fire Engineering, Department of Building Services Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong; The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China
| | - Yau Kuen Cheung
- Research Centre for Fire Engineering, Department of Building Services Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong
| | - Yang Xiao
- Research Centre for Fire Engineering, Department of Building Services Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong
| | - Xinyan Huang
- Research Centre for Fire Engineering, Department of Building Services Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong.
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Ishikura K, Hirata R, Hirano T, Okimoto Y, Wong GX, Melling L, Aeries EB, Kiew F, Lo KS, Musin KK, Waili JW, Ishii Y. Carbon Dioxide and Methane Emissions from Peat Soil in an Undrained Tropical Peat Swamp Forest. Ecosystems 2019. [DOI: 10.1007/s10021-019-00376-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Dhandapani S, Ritz K, Evers S, Yule CM, Sjögersten S. Are secondary forests second-rate? Comparing peatland greenhouse gas emissions, chemical and microbial community properties between primary and secondary forests in Peninsular Malaysia. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 655:220-231. [PMID: 30471590 DOI: 10.1016/j.scitotenv.2018.11.046] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 11/02/2018] [Accepted: 11/04/2018] [Indexed: 06/09/2023]
Abstract
Tropical peatlands are globally important ecosystems with high C storage and are endangered by anthropogenic disturbances. Microbes in peatlands play an important role in sustaining the functions of peatlands as a C sink, yet their characteristics in these habitats are poorly understood. This research aimed to elucidate the responses of these complex ecosystems to disturbance by exploring greenhouse gas (GHG) emissions, nutrient contents, soil microbial communities and the functional interactions between these components in a primary and secondary peat swamp forest in Peninsular Malaysia. GHG measurements using closed chambers, and peat sampling were carried out in both wet and dry seasons. Microbial community phenotypes and nutrient content were determined using phospholipid fatty acid (PLFA) and inductively-coupled plasma mass spectrometry (ICP-MS) analyses respectively. CO2 emissions in the secondary peat swamp forest were > 50% higher than in the primary forest. CH4 emission rates were ca. 2 mg m-2 h-1 in the primary forest but the secondary forest was a CH4 sink, showing no seasonal variations in GHG emissions. Almost all the nutrient concentrations were significantly lower in the secondary forest, postulated to be due to nutrient leaching via drainage and higher rates of decomposition. Cu and Mo concentrations were negatively correlated with CO2 and CH4 emissions respectively. Microbial community structure was overwhelmingly dominated by bacteria in both forest types, however it was highly sensitive to land-use change and season. Gram-positive and Gram-negative relative abundance were positively correlated with CO2 and CH4 emissions respectively. Drainage related disturbances increased CO2 emissions, by reducing the nutrient content including some with known antimicrobial properties (Cu & Na) and by favouring Gram-positive bacteria over Gram-negative bacteria. These results suggest that the biogeochemistry of secondary peat swamp forest is fundamentally different from that of primary peat swamp forest, and these differences have significant functional impacts on their respective environments.
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Affiliation(s)
| | - Karl Ritz
- School of Biosciences, University of Nottingham, Sutton Bonington, UK
| | - Stephanie Evers
- School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, UK; School of Biosciences, University of Nottingham Malaysia Campus, Semenyih, Malaysia; Tropical Catchment Research Initiative (TROCARI), Malaysia
| | - Catherine M Yule
- School of Science, University of the Sunshine Coast, Queensland, Australia; School of Science, Monash University, Malaysia
| | - Sofie Sjögersten
- School of Biosciences, University of Nottingham, Sutton Bonington, UK
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11
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Variation in Soil Properties Regulate Greenhouse Gas Fluxes and Global Warming Potential in Three Land Use Types on Tropical Peat. ATMOSPHERE 2018. [DOI: 10.3390/atmos9120465] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study investigated spatial factors controlling CO2, CH4, and N2O fluxes and compared global warming potential (GWP) among undrained forest (UDF), drained forest (DF), and drained burned land (DBL) on tropical peatland in Central Kalimantan, Indonesia. Sampling was performed once within two weeks in the beginning of dry season. CO2 flux was significantly promoted by lowering soil moisture and pH. The result suggests that oxidative peat decomposition was enhanced in drier position, and the decomposition acidify the peat soils. CH4 flux was significantly promoted by a rise in groundwater level, suggesting that methanogenesis was enhanced under anaerobic condition. N2O flux was promoted by increasing soil nitrate content in DF, suggesting that denitrification was promoted by substrate availability. On the other hand, N2O flux was promoted by lower soil C:N ratio and higher soil pH in DBL and UDF. CO2 flux was the highest in DF (241 mg C m−2 h−1) and was the lowest in DBL (94 mg C m−2 h−1), whereas CH4 flux was the highest in DBL (0.91 mg C m−2 h−1) and was the lowest in DF (0.01 mg C m−2 h−1), respectively. N2O flux was not significantly different among land uses. CO2 flux relatively contributed to 91–100% of GWP. In conclusion, it is necessary to decrease CO2 flux to mitigate GWP through a rise in groundwater level and soil moisture in the region.
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Li X, Guo D, Zhang C, Niu D, Fu H, Wan C. Contribution of root respiration to total soil respiration in a semi-arid grassland on the Loess Plateau, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 627:1209-1217. [PMID: 30857085 DOI: 10.1016/j.scitotenv.2018.01.313] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 01/16/2018] [Accepted: 01/30/2018] [Indexed: 05/17/2023]
Abstract
Using the trenching method, a study was conducted in a grassland on the Loess Plateau of northern China in 2008 and 2009 to partition total soil respiration (Rt) into microbial respiration (Rm) and root respiration (Rr). Using the measurements of soil CO2 diffusivity and soil CO2 production, an analytical model was applied to correct the data, aiming to quantify the method-induced error. The results showed that Rm and Rr responded differently to biotic and abiotic factors and exhibited different diurnal and seasonal variations. The diurnal variation of Rm was strongly controlled by soil temperature, while Rr might be mainly controlled by photosynthesis. The combination of soil temperature and moisture could better explain the seasonal variation in Rm (r2=0.76, P<0.001). The seasonal variation of Rr was influenced mainly by the plant activity. The contribution of root respiration to total soil respiration (Rr/Rt ratio) also exhibited substantial diurnal and seasonal variations, being higher at nighttime and lower at daytime. In the different growing stages, the Rr/Rt ratios ranged from 15.0% to 62.0% in 2008 and 14.5% to 63.6% in 2009. The mean values of the Rr/Rt ratio in the growing season and the annual mean Rr/Rt ratio were 41.7% and 41.9%, respectively, during the experiment period. Different precipitation distributions in the two years did not change the yearly Rr/Rt ratio. Corrected with the analytical model, the trenching method in small root-free plots led to an underestimation of Rr and Rr/Rt ratio by 4.2% and 1.8%.
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Affiliation(s)
- Xudong Li
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agricultural Science and Technology, Lanzhou University, P.O. Box 61, Lanzhou 730000, China
| | - Ding Guo
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agricultural Science and Technology, Lanzhou University, P.O. Box 61, Lanzhou 730000, China
| | - Chunping Zhang
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agricultural Science and Technology, Lanzhou University, P.O. Box 61, Lanzhou 730000, China
| | - Decao Niu
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agricultural Science and Technology, Lanzhou University, P.O. Box 61, Lanzhou 730000, China
| | - Hua Fu
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agricultural Science and Technology, Lanzhou University, P.O. Box 61, Lanzhou 730000, China.
| | - Changgui Wan
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agricultural Science and Technology, Lanzhou University, P.O. Box 61, Lanzhou 730000, China; Dept. Natural Resources Management, Texas Tech University, Lubbock, TX 79409, USA
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13
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Khasanah N, van Noordwijk M. Subsidence and carbon dioxide emissions in a smallholder peatland mosaic in Sumatra, Indonesia. MITIGATION AND ADAPTATION STRATEGIES FOR GLOBAL CHANGE 2018; 24:147-163. [PMID: 30662320 PMCID: PMC6320748 DOI: 10.1007/s11027-018-9803-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 03/06/2018] [Indexed: 06/09/2023]
Abstract
Most attention in quantifying carbon dioxide (CO2) emissions from tropical peatlands has been on large-scale plantations (industrial timber, oil palm (Elaeis guinensis)), differing in drainage and land-use practices from those of smallholder farms. We measured subsidence and changes in bulk density and carbon organic content to calculate CO2 emissions over 2.5 years in a remnant logged-over forest and four dominant smallholder land-use types in Tanjung Jabung Barat District, Jambi Province, Sumatra, Indonesia: (1) simple rubber (Hevea brasiliensis) agroforest (> 30 years), (2) mixed coconut (Cocos nucifera) and coffee gardens (Coffea liberica) (> 40 years), (3) mixed betel nut (Areca catechu) and coffee gardens (> 20 years), and (4) oil palm plantation (1 year). We quantified changes in microtopography for each site for greater accuracy of subsidence estimates and tested the effects of nitrogen and phosphorus application. All sites had a fibric type of peat with depths of 50 to > 100 cm. A recently established oil palm had the highest rate of peat subsidence and emission (4.7 cm year-1 or 121 Mg CO2 ha-1 year-1) while the remnant forest had the lowest (1.8 cm year-1 or 40 Mg CO2 ha-1 year-1). Other land-use types subsided by 2-3 cm year-1, emitting 70-85 Mg CO2 ha-1 year-1. Fertilizer application did not have a consistent effect on inferred emissions. Additional emissions in the first years after drainage, despite groundwater tables of 40 cm, were of the order of belowground biomass of peat forest. Despite maintaining higher water tables, smallholder landscapes have CO2 emissions close to, but above, current IPCC defaults.
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Affiliation(s)
- Ni’matul Khasanah
- Southeast Asia Regional Programme, World Agroforestry Centre (ICRAF), Jl. CIFOR, Situgede, Sindang Barang, Bogor, 16115 Indonesia
- Plant Production Systems, Department of Plant Sciences, Wageningen University and Research, 6708 PB Wageningen, the Netherlands
| | - Meine van Noordwijk
- Southeast Asia Regional Programme, World Agroforestry Centre (ICRAF), Jl. CIFOR, Situgede, Sindang Barang, Bogor, 16115 Indonesia
- Plant Production Systems, Department of Plant Sciences, Wageningen University and Research, 6708 PB Wageningen, the Netherlands
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Itoh M, Okimoto Y, Hirano T, Kusin K. Factors affecting oxidative peat decomposition due to land use in tropical peat swamp forests in Indonesia. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 609:906-915. [PMID: 28783903 DOI: 10.1016/j.scitotenv.2017.07.132] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 07/13/2017] [Accepted: 07/14/2017] [Indexed: 06/07/2023]
Abstract
The increasing frequency of fire due to drainage of tropical peatland has become a major environmental problem in Southeast Asia. To clarify the effects of changes in land use on carbon dioxide emissions, we measured oxidative peat decomposition (PD) at different stages of disturbance at three sites in Central Kalimantan, Indonesia: an undrained peat swamp forest (UF), a heavily drained peat swamp forest (DF), and a drained and burned ex-forest (DB). PD exhibited seasonality, being less in the wet season and greater in the dry season. From February 2014 to December 2015, mean PD (±SE) were 1.90±0.19, 2.30±0.33, and 1.97±0.25μmolm-2s-1 at UF, DF, and DB, respectively. The groundwater level (GWL) was a major controlling factor of PD at all sites. At UF and DF, PD and GWL showed significant quadratic relationships. At DB, PD and GWL showed significant positive and negative relationships during the dry and wet seasons, respectively. Using these relationships, we estimated annual PD from GWL data for 2014 and 2015 as 698 and 745gCm-2yr-1 at UF (mean GWL: -0.23 and -0.39m), 775 and 825gCm-2yr-1 at DF (-0.55 and -0.59m), and 646 and 748gCm-2yr-1 at DB (-0.22 and -0.62m), respectively. The annual PD was significantly higher in DF than in UF or DB, in both years. Despite the very dry conditions, the annual PD values at these sites were much lower than those reported for tropical peat at plantations (e.g., oil palm, rubber, and acacia). The differences in the relationship between PD and GWL indicate that separate estimations are required for each type of land. Moreover, our results suggest that PD can be enhanced by drainage both in forests and at burned sites.
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Affiliation(s)
- Masayuki Itoh
- Center for Southeast Asian Studies, Kyoto University, Kyoto 606-8501, Japan.
| | - Yosuke Okimoto
- Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Takashi Hirano
- Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Kitso Kusin
- CIMTROP, University of Palangkaraya, Palangkaraya, 73112, Indonesia
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