Shallow Peatland Research Articles

Performance of sorghum varieties with various fertilizer doses in peatlands of West Aceh Regency

West Aceh Regency is one of the regions in Indonesia with quite extensive peatlands, but the diversity of food crop commodities is still very low. To enhance food diversification programs of rice, sorghum production is important. The purpose of this research was to test several varieties of sorghum in the peatlands of West Aceh Regency. This research was carried out from July to November 2023. Several new varieties of sorghum released by the Indonesian Cereals Research Institute (ICERI) were evaluated in the peatland of West Aceh. The research method used a randomized complete block design (RCBD) with two factors and three replications. The first factor was different varieties of sorghum, and the second factor was various doses of fertilizers. The varieties used were Soper 7 Agritan, Bioguma 1, and Suri 3. The doses used Control (no treatment), Dose I (75 kg Urea ha-1 + 50 kg SP-36 ha-1 + 50 kg KCl ha-1), Dose II (150 kg Urea ha-1 + 100 kg SP-36 ha-1 + 100 kg KCl ha-1), and Dose III (225 kg Urea ha-1 + 150 kg SP-36 ha-1 + 150 kg KCl ha-1). The results showed that the Bioguma 1 variety adapted better than the other varieties, where the plant height was 187.97 cm, the number of leaves was 15.08, the panicle diameter was 35.92 mm, and the panicle weight was 79.52 g. Meanwhile, fertilizer dose II is better on the character of the number of leaves and panicle length. The interaction effect between the two factors only showed a significant influence on panicle length. Therefore, the Bioguma 1 sorghum variety can be a recommended variety for planting in the shallow peatlands of West Aceh. Keywords: Acidic soil; alternative food; food diversification

The effects of temperature on plasticity, shape symmetry and seasonal variation in the freshwater benthic green microalga Micrasterias thomasiana

Desmids are usually abundant in shallow peatland pools. In these localities, water temperature is closely linked to seasonal fluctuations in air temperature, so with increasing temperature extremes in temperate ecosystems, these microalgae are exposed to conditions of high-temperature stress. We investigated whether the shape, size, and growth rates of Micrasterias thomasiana, a frequently occurring species, are associated with varying temperatures in cultures and natural populations. The research was based on parallel analysis of clonal populations in temperature levels from 13 to 33 °C as well as cells from natural populations collected during the season. The effects of high temperature on morphological plasticity and fluctuating asymmetry in the shape of cellular parts were investigated by the landmark-based geometric morphometrics. The results showed that variation among individuals and fluctuating asymmetry between the lateral lobes of Micrasterias cells increased at 29 °C and in natural samples taken in July and October. In parallel, the size of semicells growing at temperatures above 25 °C decreased compared to those grown at lower temperatures. However, the temperature effects on shape and size were not directly related to the growth rates. The overall bilateral asymmetry between semicell halves did not change in relation to varying temperatures. In general, the results showed that morphological variation in natural populations of M. thomasiana reflected seasonal cycles and corresponded to plasticity associated with temperature changes in clonal cultures. It might therefore be possible to use these phenotypic markers as indicators of thermal stress in natural populations inhabiting shallow pools in peatlands.

Hubungan Evapotranspirasi, Hujan dan Elevasi Muka Air Tanah pada Lahan Gambut Tropis Sebagai Awal Penentuan Kondisi Lahan Basah

The relationship between parameters in wetlands, especially peatlands, as a part of the analysis is interesting to study. The analysis is expected to show the condition of the peatland or the state of the wetlands in general. The water table elevation (WTE) is measured daily, so to compare it with evapotranspiration and rain, daily values for these two parameters are also required. The study was conducted between June-July and August 2022 on shallow peatlands in Gambut District, Banjar Regency, South Kalimantan Province. Evapotranspiration in this study was calculated using the Hargreaves and Modified Hargreaves method which presents a daily evapotranspiration calculation. The methods only depend on the maximum and minimum temperature, the number of outer space radiation whose magnitude depends on its location on the earth's surface, and the time when the research is conducted. The results showed that the highest daily evapotranspiration value generally occurred in August, which was in accordance with previous studies, but the magnitudes were different. The daily evapotranspiration value in this study ranged from 0.5 mm to 1.8 mm, while previously, the values were greater. WTE values show a strong relationship with rainfall, where rainfall increases the WTE value, and conversely, the absence causes the WTEs to decrease gradually. In general, the condition of the peatlands in the study area based on the groundwater elevation conditions still looks quite good with a fast response to rain. The relationship of evapotranspiration with rain and water table elevation cannot be clearly seen in this study because alterations in rainfall and WTE do not directly indicate changes in evapotranspiration values, so a more extended study covering other months and more in-depth covering parameters and other methods is needed to draw valid conclusions more accurate.

Edukasi Water Management kepada Masyarakat: Mencegah Kebakaran Lahan Gambut dan Pemanfaatan Lahan Gambut untuk Pertanian di Desa Kuta Padang Kabupaten Aceh Barat

Education activities on water management and peatland utilization were carried out in Kuta Padang Villages, Bubon Subdistrict, West Aceh Regency. Involving 20 participants, including village officials, this water management education emphasized the importance of peat rewetting (Rewetting) and canal closure as the main strategies in addressing degradation and the risk of peatland fires. Through the Focused Group Discussion (FGD) method, participants were taught about fluctuations in groundwater levels, the identification of canal blocking construction, and the utilization of peatlands for agriculture. The results of the activity showed an increase in community understanding of the impact of peatland ecosystem damage and its connection to land fires. Education also discussed fluctuations in groundwater levels as a crucial element in water management, providing a better understanding of groundwater dynamics in peatlands. The selection of efficient food and horticultural crops for shallow peatlands became a focus in land utilization for agriculture.

Climate-smart peatland management and the potential for synergies between food security and climate change objectives in Indonesia

Tropical peatlands lie at a nexus of competing sustainable development demands of enhancing food security, mitigating climate change, improving resilience and supporting rural livelihoods. Meeting United Nations Sustainable Development Goals (SDGs) requires balancing these various demands. Progress in meeting SDGs has been slow in low to middle income countries because of difficulties in identifying and quantifying the trade offs associated with natural resource exploitation, including on extensive areas of tropical peatlands.Here, by using secondary data from the literature, Indonesian and international agencies, we examine how land-use allocation in Indonesia has developed over the last three decades by investigating trends of key food and woody crops (oil palm and rubber) and evaluate the role that peatland provinces have played in food security and climate forcing. Overall, food crop production has been marginal in peatland provinces compared to monoculture woody crops, with the latter associated with increased carbon emissions from land use, land-use change, and forestry (LULUCF) over the last thirty years. Our analysis shows that synergies between responses to looming food security and climate change crises can also promote less damaging forms of tropical peatland management. For instance, the conversion of degraded shallow peatlands to agroecological practices (e.g., paludiculture) can be promoted. However, we stress that peatland conservation and restoration must remain the top priority. Impediments due to lack of a common definition for peatland and planning/management units, the use of multiple sectoral maps by different government agencies and uncoordinated sectoral policy targets can, however, hinder the implementation of less damaging peatland management.

Analysis of water physical, chemical and biological properties in different peat swamp forests converted to rice fields

The Indonesian government plans to turn Central Kalimantan into a national food barn by planting rice in several places, including in shallow peatlands. Tropical peatlands actually have limited potential for agricultural use because the growing medium in some cases is not conducive to root development, waterlogged soils that poison plants. The physical, chemical, and biological properties of water can be used as indicators to determine if a land is suitable for growing crops. The objective of this study is to analyze the physical, chemical, and biological properties of water in different aquatic ecosystems in peat swamp forest. This study was conducted in the Peat Techno Park (PTP) of the College of Palangka Raya, Central Kalimantan. Samples were collected from 9 observation stations with different forms of land use for agricultural activities, namely unplowed rice fields, plowed fields, swamps, connecting ditches, beje, natural peat swamp forests, ponds and irrigation ponds. Data collection was taken over a 6-month period and coincided with the peak of the dry season and the rainy season. Water properties were then analyzed by observing the parameters measured directly at the station, namely pH, temperature, dissolved oxygen (DO) and depth. The results showed that there were 4 (four) sites that had suitable water properties for agricultural uses, namely unplowed fields, plowed fields, swamps and ponds. There are only 2 (two) macrozoobenthos groups on PTP peat bogs, namely Annelida and insects. In addition, the most dominant group in insect belongs to the ordo Diptera, and family Chironomidae with the most common genus Chironomus. Conversion of peat swamp forest to rice fields and fish ponds promotes greater diversity and abundance of macroinvertebrate communities, with the depth significantly affecting them.

The Influence of Shallow Peatland Water Quality on Characteristics of the Occurrence of Selected Herb Species in the Peatlands of Eastern Poland

The aim of the analysis was to compare the physicochemical variables of the quality of shallow groundwater in the peatlands of Eastern Poland in the context of the occurrence of selected herb species with similar habitat requirements: bogbean (Menyanthes trifoliata), small cranberry (Oxycoccus palustris), and purple marshlocks (Comarum palustre). The analysis of the quality variables of the shallow groundwater included the following physicochemical variables: reaction (pH), electrolytic conductivity (EC), dissolved organic carbon (DOC), total nitrogen (Ntot.), ammonium nitrogen (N-NH4), nitrite nitrogen (N-NO2), nitrate nitrogen (N-NO3), total phosphorus (Ptot.), phosphates (P-PO4), sulphates (SO2), sodium (Na), potassium (K), calcium (Ca), and magnesium (Mg). Internal metabolism was shown to influence the hydro-chemical status of peatland water, free of substantial human impact. The variables tested were within the range of the habitat preferences of the herb species and indicated that they have a wide ecological tolerance. However, their identical habitat preferences were not reflected in identical values for the physicochemical variables of the water essential for building populations of these species. The occurrence of these plant species was also shown to be determined by the hydro-chemical characteristics of the habitat, but the characteristics of their occurrence did not indicate the hydro-chemical aspect of the habitat.

Reduced Net CO2 Uptake During Dry Summers in a Boreal Shield Peatland

AbstractPeatlands are globally important long‐term sinks of atmospheric carbon dioxide (CO2). However, there is concern that climate change‐mediated drying will reduce gross primary productivity (GPP) and increase ecosystem respiration (ER) making peatlands vulnerable to a weaker carbon sink function and potential net carbon loss. While large and deep peatlands are usually resilient to moderate summer drying, CO2 exchange in shallow Boreal Shield peatlands is likely more sensitive to drying given the reduced groundwater connectivity and water storage potential. To better understand the carbon cycling responses of Boreal Shield peatlands to meteorological conditions, we examined ecohydrological controls on CO2 fluxes using the eddy covariance technique at a shallow peatland during the summer season for 5 years, from 2016–2020. We found lower GPP in dry summer years. Mean summer water table depth (WTD) was found to be significantly correlated with summer total net ecosystem CO2 exchange (R2 = 0.78; p value = 0.046) and GPP (R2 = 0.83; p value = 0.03), where wet summers with a WT close to the peat surface sequestered more than twice the amount of CO2 than dry summers. Our findings suggest that shallow Boreal Shield peatland GPP may be sensitive to climate‐mediated drying as they may switch to a net CO2 source in the summer season when WTDs exceed a critical ecohydrological threshold for a prolonged period of time.

Caracterización limnológica, estructura del fitoplancton y batimetría de Laguna Negra, un lago coloreado del Parque Nacional Tierra del Fuego (Argentina)

The 4% of the Argentinian sector from Tierra del Fuego is covered with water. Colored lakes are among the most conspicuous water bodies in the Andean area, and Laguna Negra, in the National Park Tierra del Fuego, is one of them. The main physical and chemical variables were monitored and phytoplankton samples were obtained with a monthly frequency during the ice-free period, between September 2016 and March 2018 (n=15). Laguna Negra was deeper than expected, with a maximum depth of 15.5 m. In addition, this lake has high pH values (7.5±0.55), which were quite stable during the study (variation coefficient, VC=8.3%). These characteristics preclude us from considering this lake as a shallow peatland lake. Dissolved and total nutrients were low and did not show a temporal pattern of fluctuation during the study period. The same trend of no clear fluctuation was also shared by dissolved organic carbon concentration (DOC=7.7±0.78 mg/L). Taxa richness ranged between 6 and 13 throughout the study. The biovolume was inversely correlated with the vertical attenuation coefficient of light (Kd). Phytoplankton biomass (chlorophyll-a concentration, abundance, and biovolume) was generally low, with Dinobryon divergens, Mallomonas sp. and Parvodinium cf. inconspicuum being the dominant taxa. Depending on the classification used, Laguna Negra might be regarded as a humic or dystrophic lake because its color is at the edge of values used in the current literature to consider a lake as humic.

Distribution of Carbon Stocks in Peat Bottom Based on Thickness Class in Pelalawan Village (Riau Province, Indonesia)

As is well known, tropical peatlands are deposits of terrestrial organic carbon of global importance. It is estimated that around 15% of carbon is stored in peatlands worldwide. Indonesia contains approximately 50% of the world’s tropical peatlands with frequently cited estimates of about 21 Mha. Pelalawan district area (Riau Province) is dominated by peat soils. The land in Pelalawan is mainly covered by industrial plantations of acacia forests and oil palms. The area is very susceptible to the loss of carbon stocks in peat soils due to the opening of drainage channels. This study aims to calculate the carbon stocks of subsurface peatlands in Pelalawan, especially in the research location. The method used is a grid survey, the distance between the particular points is 500 m, which covers the total area of the research site, i.e. 2,500 ha. The number of observation points is 121, which includes measuring the thickness of the peat layer, calculating bulk density, and C organic content. The paper analysed the distribution of carbon stocks in the peat bottom based on the thickness class. The results showed that carbon stocks in the peat bottom in Pelalawan were 218,753.95 tons/ha consisting of 143,138.40 tons/ha in the peat thickness of >300 cm (very deep peatland), 44,999.10 tons/ha in the peat thickness of 200–300 cm (deep peatland), 21,577.67 tons/ha in the peat thickness of 100–200 cm (medium peatland), 4,780.78 tons/ha in the peat thickness of 50–100 (shallow peatland), and 4,258 tons/ha in the peat thickness of 0–50 (very shallow peatland). The research results of this study cover the information on the availability of carbon storage and carbon conservation.

Effects of two contrasting potting media on the leaf development index, photosynthetic rate, and metabolite profile of camphor (Dryobalanops aromatica) seedlings

Camphor (Dryobalanops aromatica C. F. Gaertn.) is a vulnerable tropical tree species that has been exploited for its timber as well as its resin, which is used for medicinal uses. The use of camphor in Indonesia is limited owing to the decreasing size of the species' population in its native habitat. Therefore, replanting programs have been encouraged for this species owing to its adaptability to mineral soils and shallow peatlands. However, experimental evidence of the effect of different growing media on morphology, physiology, and biochemistry is very limited, which is needed to evaluate the replanting program's success. Therefore, this study aimed to determine the responses of camphor (D. aromatica) seedlings grown in two different types of potting media i.e. mineral and peat, for 8 weeks of planting. In particular, the types of bioactive compounds produced in camphor leaves and their levels were assessed by analyzing their metabolite profiles. Leaf growth was evaluated morphologically using the plastochron index, while photosynthetic rates were measured with LI-6800 Portable Photosynthesis System. Metabolites were identified by using liquid chromatography-tandem mass spectrometry. The percentage of LPI of 5 or more was lower in the peat medium at 8% than in the mineral medium at 12%. The photosynthetic rate of camphor seedlings was 1–9 μmol CO2 m⁻2 s⁻1, with a higher rate in the peat medium than in the mineral medium, suggesting that the peat medium was better for growth. Lastly, the metabolomic analysis in the leaf extract revealed the presence of 21 metabolites, which were dominated by flavonoid compounds.

The dynamics of benthic invertebrates in different part of peat swamp forests converted to rice fields

The Indonesian government plans to turn Central Kalimantan province into a national food barn by planting rice paddies in several places, including in shallow peatlands. Tropical peatlands have limited potential to be used as agricultural land since the growing media in some cases, is not conducive to root development, saturated-water soil that poissons the plants. Aquatic invertebrates can be used as indicators to determine whether water quality in a field is safe for plants or not. The objective of this study is to evaluate the dynamics of benthic in different part of aquatic ecosystems on peat swamp forests. This study was conducted in Peat Techno Park (PTP) of the University of Palangka Raya, Central Kalimantan. Samples were collected from 9 stations with different forms of land use for agricultural activities, namely unplowed paddy fields, plowed fields, swamps, connecting ditches, beje, natural peat swamp forests, breeding ponds, and irrigation ponds. Data were collected over 6 months and coincided with the peak of dry and wet seasons. The abundance and species of aquatic invertebrates were then analyzed some related physic-chemical parameters, such as depth, water temperature, pH, and dissolved oxygen (DO). The results showed that the macrozoobenthos species found on this study was slightly rare. There was identified merely 3 genera, include in the two benthic groups, e.i. Annelida and insect. As to the insect, the dominant species was from the order of Diptera and family of Chironomidae, especially Chironomus. Spatially, stations 1 (unplowed rice fields), 2 (ploughed rice fields), 3 (peat swamp forest), 7 (cultivated ponds), and 9 (new beje) were particularly abundant. In this case, the conversion of peat swamp forests to rice fields and fish culture ponds will possibly promote greater diversity and abundance of macroinvertebrate communities.

Determining Carbon Dioxide Emission Response in Soil Microcosms from a Shallow Mid-Atlantic Peatland: The Influence of Water Table Restoration

Johnson, A.M.; Atkinson, R.B.; Steven, J.C.; Whiting, G.; Napora, K.; Sharrett, L., and Mirda, C., 2022. Determining carbon dioxide emission response in soil microcosms from a shallow mid-Atlantic peatland: The influence of water table restoration. Journal of Coastal Research, 38(2), 261–268. Coconut Creek (Florida), ISSN 0749-0208. Determining carbon dioxide emission response in shallow microcosms from a shallow mid-Atlantic peatland: The influence of water table restoration. Peatlands provide ecosystem services such as pollution filtration, flood control, and carbon storage as these ecosystems contain 33% to 50% of the global soil carbon pool. Reestablishing soil saturation in degraded peatlands can limit microbial oxidation of organic matter; however, drainage history may alter soil saturation patterns and challenge restoration efforts. The purpose of this study was to investigate carbon emission response to water table restoration for two shallow peatlands including a Histosol and an Ultisol with divergent drainage histories. Soil cores were gathered from the top 22.5 cm of organic-rich surface horizons within Cavalier Wildlife Management Area in Chesapeake, Virginia. Cores were randomly assigned to four water level treatments that simulated restoration conditions, and carbon dioxide emissions were measured using an LI-6400XT portable open-flow photosynthesis system twice a week for 4 weeks. Despite higher organic matter content in the long-drained site, emissions (2.1 to 3.9 µmol CO2 m–2 s–1) were higher than at the historically less drained site (1.5 to 2.3 µmol CO2 m–2 s–1). Volumetric water content trends revealed that longer-drained soils retained lower water content within restoration treatments and were associated with higher carbon emissions. Restoration of long-drained peats in the mid-Atlantic region may require higher water tables than otherwise predicted to overcome a resistance to rewetting where limiting microbial soil respiration is a management objective.

Peat depth as a control onSphagnummoisture stress during seasonal drought

AbstractPeatlands are globally important long‐term sinks of carbon, however there is concern that enhanced peat decomposition and moss moisture stress due to climate change mediated drought will reduce moss productivity making these ecosystems vulnerable to carbon loss and associated long‐term degradation. Peatlands are resilient to summer drought moss stress because of negative ecohydrological feedbacks that generally maintain a wet peat surface, but where feedbacks may be contingent on peat depth. We tested this ‘survival of the deepest’ hypothesis by examining water table (WT) position, near‐surface moisture content, and soil water tension in peatlands that differ in size, peat depth, and catchment area during a summer drought. All shallow sites (<40 cm depth) lost their WT (i.e., the groundwater well was dry) for considerable time during the drought period. Near‐surface soil water tension increased dramatically at shallow sites following WT loss, increasing ~5–7.5× greater at shallow sites compared to deep sites (≥40 cm depth). During a mid‐summer drought intensive field survey, we found that 60–67% of plots at shallow sites exceeded a 100 mb tension threshold used to infer moss water stress. Unlike the shallow sites, tension typically did not exceed this 100 mb threshold at the deep sites. Using species dependent water content – chlorophyll fluorescence thresholds and relations between volumetric water content and WT depth, Monte Carlo simulations suggest that moss had nearly twice the likelihood of being stressed at shallow sites (0.38 ± 0.24) compared to deep sites (0.22 ± 0.18). This study provides evidence that mosses in shallow peatland may be particularly vulnerable to warmer and drier climates in the future, but where species composition may play an important role. We argue that a critical ‘threshold’ peat depth specific for different hydrogeological and hydroclimatic regions can be used to assess what peatlands are especially vulnerable to climate change mediated drought.

Агроекологічний моніторинг осушуваних органогенних ґрунтів Лівобережного Лісостепу України

Goal. To monitor drained organogenic soils for their long-term agricultural use and based on analysis of the obtained data to determine ways to optimize the properties of drained peat-lands and to assess their ecological status in the future. Methods. System analysis, field, laboratory, analytical, computational, and mathematical and statistical. Results. It is established that for the 36 years of agricultural use of peat soils the decrease in peat thickness on average per year on shallow peat-lands is 0.7 cm, medium-deep — 1.2, deep — 1.5 cm, density (bulk density) increased on average almost in 1.4 times, and the total moisture content decreased in 1.6 times. Peat became multi-ash (47–59%), and almost no acidity was observed in the soil (pHwater — 7.4–7.8%). The amount of gross phosphorus increased on average by 6–8%, nitrogen, depending on the method of use decreased by 8-10%, the amount of potassium remained unchanged. Conclusions. To normalize the ecological situation and the balanced and rational use of drained peat-lands, plant communities should be created on these lands with maximum proximity to natural ecosystems, in particular, to grow perennial grasses for fodder purposes and energy crops with a 20–25 year cycle. That optimizes peat mineralization processes and will ensure the productivity of perennial grasses at the level of 8.14 t/ha of dry matter and energy crops, willow — 39.40 t/ha, miscanthus giant — 25.73 t/ha of dry matter, or 669.8 GJ/ha and 437.4 GJ/ha of energy.

Drain blocking has limited short-term effects on greenhouse gas fluxes in a Molinia caerulea dominated shallow peatland

Drained peatlands dominated by purple moor grass (Molinia caerulea) are widespread in the UK and Western Europe. Although substantial carbon stores may be present in these peatlands, in this degraded state they are not currently acting as carbon sinks. Therefore, M.caerulea dominated peatlands have been identified as potential sites for ecohydrological restoration to tackle the current climate emergency. However, at present little is known about whether ditch blocking can raise water tables and promote the recovery of bog plant species, and the subsequent effects on carbon sequestration in these peatlands.To investigate the potential for restoration, we measured changes in water table depth, vegetation composition, photosynthesis at 1000 μmol Photons m−2 s−1 (PG1000), ecosystem respiration (REco) and partitioned below-ground respiration in two M.caerulea dominated peatlands in which drainage ditches had been blocked located in Exmoor National Park, southwest England. Measurements were made in two headwater catchments at ⅛, ¼ and ½ of the distance between adjacent drainage ditches at four control-restored paired sites, during the growing seasons pre- (2012) and post- (2014, 2016 & 2018) restoration.Restoration had a small but significant (p = 0.009) effect on water table depths however, this did not result in a significant change in vegetation composition (p > 0.350). Ecosystem respiration increased in both the control and restored locations following restoration however, this increase was significantly smaller (p = 0.010) at the restored locations, possibly due to a similarly reduced increase in photosynthesis, although this change was not significant (p = 0.116). Below-ground respiration showed no significant changes following restoration.This research illustrates how degraded these shallow peatlands are, and raises concerns that ditch blocking alone may not bring about the high and stable water tables required to perturb the existing Molinia caerulea-dominated ecosystem and substantially alter the carbon balance. Additional restoration measures may be required.

Shallow peat is most vulnerable to high peat burn severity during wildfire

Peatlands typically act as carbon sinks, however, increasing wildfire severity and annual area burned may challenge this carbon sink status. Whilst most peat resistance to wildfire and drought research is based on deep peatlands that rarely lose their water table below the peat profile, shallow peatlands and peat deposits may be most vulnerable to high peat burn severity and extensive carbon loss. To examine the role of pre-fire peat depth on peat burn severity, we measured the depth of burn (DOB) in peat of varying depths (0.1–1.6 m) within a rock barrens landscape. We found that DOB (0–0.4 m) decreased with increasing pre-fire peat depth, and that there was a strong correlation between the percent of the profile that burned and pre-fire peat depth. Breakpoint analysis indicates a threshold depth of 0.66 m where deeper peat deposits experienced little impact of wildfire, whereas shallower peat typically experienced high peat burn severity (median percent burned = 2.2 and 65.1, respectively). This threshold also corresponded to the loss of the water table in some nearby unburned peatlands, where water table drawdown rates were greater in shallower peat. We suggest that peat depth may control peat burn severity through feedbacks that regulate water table drawdown. As such, we argue that the identification of a critical peat depth threshold could have important implications for wildfire management and peatland restoration aiming to protect vulnerable carbon stores.

New Approach Evaluating Peatland Fires in Indonesian Factors

Until 2018, the El Niño–Southern Oscillation (ENSO) was used as an explanation for fires in Indonesia’s peatlands. However, when the 2019 fires occurred independently of El Niño, more suitable indicators and methods were required to (a) analyze, (b) evaluate and (c) forecast peatland fires. In this study, we introduced the OLR–MC index—one of the rain-related indices derived from OLR (outgoing longwave radiation) in MC (maritime continent) area in Indonesia. This index showed stronger correlation with active peatland fires than the conventional ENSO index, and is likely to be able to respond to heat and dry weather supposed to be under climate-change conditions. We then analyzed peatland fires in the top six fire years from 2002 to 2018 and showed that peatland fires occurred in three stages—surface fire, shallow peatland fire and deep peatland fire. To explain each stage, we proposed a one-dimensional groundwater level (GWL) prediction model (named as MODEL-0). MODEL-0 predicts GWL from daily rainfall. Analysis using MODEL-0 showed the GWL thresholds for the three fire stages were between -300 mm and -500 mm; peatland fire activities during the three fire stages were dependent on these GWL values. The validity of MODEL-0 was shown by comparison with the measured values of GWL in the top three fire years.

Amelioratory plowing of peat bogs and substantiation of the basic parameters of a double-cut plow

Drained peat soils in Belarus occupy 11.3 % of agricultural land. These soils lost their genetic traits on the area of almost 260 thousand hectares, and moved into the category of anthropogenically transformed, over 190 thousand hectares of those – into the category of degraded. The most important condition for improving the properties of low-ash peat soils is an increase of ash elements level – up to 50–70 % in the plowing layer. The anthropogenically formed layer-mixed culture of soil profile with deep reclamation plowing method corresponds to this to the fullest extent. Its use is important on shallow peatlands that quickly lose their organic layer. It has been determined that the depth of such plowing is determined both by the thickness of peat bog and by the thickness of plowed mineral soil (sand or sandy loam). Based on the obtained analytical expressions, analysis of process layouts for formation of new soil profile by the plow, taking into account availability of peat soil areas according to deposit capacity, feasibility of using two types of special plows is substantiated: double-cut mounted type with plowing depth of 50–100 cm and single-cut trailed type with plowing depth of 90–150 cm. Technologically rational is plow operation according to layout with undercut equal to the width of sandy layer in sub-plowing horizon. At the same time, the interval of rational values of structural width of double-cut plow grip (on the II cut body) b k = 50–67 cm, and the width of plow grip shall not exceed 100 cm. Ratio of its actual value to the accepted design width of the bodies is in the range of (5 : 4)–(2 : 1) depending on agrotechnical requirements. The designed PTN-0.9 double-cut plow for deep amelioratory plowing has passed acceptance tests and is recommended for serial production. The result of the study is theory of dump plowing. The results allow for development of special double-cut plows for deep amelioratory treatment of shallow peat bogs, which ensures their preservation during agricultural use.

FRAKSI BESI DAN PENGARUHNYA TERHADAP KELARUTAN POSFOR DI LAHAN RAWA (Iron Fraction And Its Effect On Posforning Sustainability In Rawa Land)

ABSTRACTAbout 20 million Ha of tidal swampare found in Indonesia,6.7 million ha of them are acid sulphatesoils which associated with peatland.Most of soil in tidal swamp are rich in iron, it potentialy toxicto the plant. We critically examine the presence of peat matter as surface layer to iron fraction andthe role of ferrous to phosphorus (P) solubility in soil.Iron fractions analyzed in acid sulphate soil,peaty acid sulphate soil, shallow peatland, shallow peatland which all of peat layers were removedand shallow peatland which partially of peat layers were removed. Most of iron fraction in tidalswampland which covered by peat layer is organic-Fe form, the presence of peat layer on surfacelayer caused no correlation between Fe and P in soil.Key words : Acid sulphate soil, Iron, Peatland, Phosphorus andTidal swampland