Shallow Peat Research Articles

Simulating controlled drainage and hydrological connections in a cultivated peatland field

AbstractCultivated peatlands are increasingly regarded as hot spots due to climate change and other environmental concerns. Flexible water management, such as controlled drainage, is proposed to optimize cultivation and reduce environmental risks in peatland fields. The hydrological and environmental implications of controlled drainage depend on site‐specific variables, and it is unclear how controlled drainage should be implemented in various conditions. Simulation models are a promising approach to systemically study the field hydrology, as models can capture the complete water balance, which is difficult through experimental studies alone. We calibrated and validated the spatially distributed model FLUSH to describe the hydrology of a field block with a shallow peat cover and controlled drainage in central western Finland. The objectives were to analyze the hydrological effects of controlled drainage and detect hydrological connections between the field and an adjacent upslope forest area. The results showed how inflow from the forest can induce high observed drain discharge but impacted the block groundwater tables only in the proximity of the forest (distance <25 m). The effect of controlled drainage on groundwater tables was on average 0.15 m and seasonally varying. Controlled drainage reduced drain discharge, and the reduction was larger with the forest area included in the model. While controlled drainage effects on groundwater levels and soil moisture were insensitive to groundwater influxes from adjacent areas, the water balance impact highlights the role of hydrological connections in the hydrology of cultivated peatlands under controlled drainage.

Microbial communities and functions are structured by vertical geochemical zones in a northern peatland

Northern peatlands are important carbon pools; however, differences in the structure and function of microbiomes inhabiting contrasting geochemical zones within these peatlands have rarely been emphasized. Using 16S rRNA gene sequencing, metagenomic profiling, and detailed geochemical analyses, we investigated the taxonomic composition and genetic potential across various geochemical zones of a typical northern peatland profile in the Changbai Mountains region (Northeastern China). Specifically, we focused on elucidating the turnover of organic carbon, sulfur (S), nitrogen (N), and methane (CH4). Three geochemical zones were identified and characterized according to porewater and solid-phase analyses: the redox interface (<10 cm), shallow peat (10–100 cm), and deep peat (>100 cm). The redox interface and upper shallow peat demonstrated a high availability of labile carbon, which decreased toward deeper peat. In deep peat, anaerobic respiration and methanogenesis were likely constrained by thermodynamics, rather than solely driven by available carbon, as the acetate concentrations reached 90 μmol·L−1. Both the microbial community composition and metabolic potentials were significantly different (p < 0.05) among the redox interface, shallow peat, and deep peat. The redox interface demonstrated a close interaction between N, S, and CH4 cycling, mainly driven by Thermodesulfovibrionia, Bradyrhizobium, and Syntrophorhabdia metagenome-assembled genomes (MAGs). The archaeal Bathyarchaeia were indicated to play a significant role in the organic carbon, N, and S cycling in shallow peat. Although constrained by anaerobic respiration and methanogenesis, deep peat exhibited a higher metabolic potential for organic carbon degradation, primarily mediated by Acidobacteriota. In terms of CH4 turnover, subsurface peat (10–20 cm) was a CH4 production hotspot, with a net turnover rate of ∼2.9 nmol·cm−3·d−1, while the acetoclastic, hydrogenotrophic, and methylotrophic methanogenic pathways all potentially contributed to CH4 production. The results of this study improve our understanding of biogeochemical cycles and CH4 turnover along peatland profiles.

The Growth and Carbon Sink of Tundra Peat Patches in Arctic Alaska

AbstractRecent amplified climate warming in the Arctic has caused profound changes in terrestrial ecosystems, with the potential for strong feedback on climate change. Arctic tundra landscapes have developed patchy and thin organic soil (peat) layers at the surface that may continue to grow into mature peatlands and become a larger carbon sink under future warming. Here we use paleoecological analyses of multiple soil and peat cores collected from the North Slope of Alaska to document and understand the formation and development histories of tundra peat patches and permafrost peatlands. We find a consistent peat development sequence for peat patches, first from mineral soils to sedge peat during the Little Ice Age, and then to Sphagnum peat during the recent warming with high carbon accumulation rates. These findings suggest that climate cooling is likely critical for the initial peat buildup on tundra soils due to reduced decomposition, whereas climate warming triggers the regime shift into an increased abundance of Sphagnum mosses that are likely central to enhancing their carbon sink capacity. Additionally, peat patches become similar to permafrost peatlands in the vicinity in terms of ecosystem processes and carbon dynamics, and therefore may have developed the same ecohydrological feedback system to maintain their long‐term stability. This study implies that the potential future expansion of peat patches into peatlands may strongly alter the carbon balance of Arctic tundra, supporting the new United Nations Environment Programme's report that calls for incorporating widespread shallow peat into understanding the peatland–carbon–climate nexus.

Mapping and monitoring peatlands in the Belgian Hautes Fagnes: Insights from Ground-penetrating radar and Electromagnetic induction characterization

Peatlands are vital ecosystems providing crucial ecological services such as significant carbon storage in the context of climate change. These sensitive ecosystems are subjected to degradation due to land use change. In this context, it is important to understand the actual state of degraded peatlands and their recovery potential for regaining important functions. This study focuses on a disturbed peatland in the Belgian Hautes Fagnes, previously drained and planted with spruce, and characterized by a topographic gradient. We aimed to elucidate the use of Ground-penetrating radar (GPR) and Electromagnetic induction (EMI) techniques in characterizing such peatlands, with a specific focus on their implications for peat depth and electrical conductivity assessment, related to peatland degradation. The GPR revealed a high spatial heterogeneity in peat depth, ranging from 0.2 to more than 2 m on the site. In contrast, an EMI instrument used with single coil spacing proved to be unsuccessful to deduce peat depth but demonstrated potential for the delineation of zones of mineral soil. It is also shown that the links between soil physical and chemical properties and its bulk soil electrical conductivity (ECa) measured by EMI are complex in zones of shallower peat. Additionally, this study highlights the role of pore water conductivity in influencing temporal variations in ECa. Our findings explain the intricate interplay between peat depth, topography and ECa in disturbed peatlands. The results of this study may be of substantial societal interest, as it provides insights into techniques for the rapid non destructive characterization of the conditions of previously drained peatlands.

Impact of iron addition on phosphorus dynamics in sediments of a shallow peat lake 10 years after treatment

Internal phosphorus (P) loading is a key water quality challenge for shallow lakes. Addition of iron (Fe) salts has been used to enhance P retention in lake sediments. However, its effects on sediment geochemistry are poorly studied, albeit pivotal for remediation success. Here, we assess the factors controlling the retention of P and long-term effects following application of FeCl3 (0.5–1 mol Fe/m2, 2010) in the eutrophic, shallow peat lake Terra Nova (the Netherlands). Treatment reduced P levels in the lake for two years, but afterwards summer release of P intensified, resulting in higher surface water P concentrations than before treatment. Porewater and sediment analyses indicate that the majority of the added Fe is still undergoing redox cycling within the top 10 cm of sediment accounting for the binding of up to 70 % of sedimentary P. Sequential extractions further suggest that organic matter (OM) plays a key role in the resulting P and Fe dynamics: While reduction of P binding Fe(III) phases results in P release to porewaters, the produced Fe2+ remains bound to the solid phase presumably stabilized by OM. This causes P release from the sediments in excess to Fe during temporary low oxygen conditions in summer months, as confirmed by whole core flux incubation experiments. Quantitative coprecipitation of P with Fe upon reoxygenation of the water body is then impossible, leading to a gradual increase in surface water P. This first long-term study on a shallow peat lake underpins the role of OM for Fe cycling and the need to carefully consider the sediment properties and diagenetic pathways in the planning of Fe-amendments.

LIFE CYCLE AND DEVELOPMENT PERIODS OF OIL PALM POLLINATING WEEVIL, ELAEIDOBIUS KAMERUNICUS FAUST, 1878 (COLEOPTERA: CURCULIONIDAE) FROM OIL PALM PLANTATIONS IN MALAYSIA

The pollinating weevil, Elaeidobius kamerunicus, was introduced to Malaysia in 1981 to foster the production of oil palm fruit bunches. The weevil plays a significant role in the pollination of oil palm. This study aims to determine the life cycle, development period, body size and longevity of oil palm pollinating weevils in four different types of soils in Malaysia, namely: shallow peat soil [Malaysian Palm Oil Board (MPOB) Teluk Intan], deep peat soil (MPOB Sessang), mineral soil (MPOB Long Danau) and clay soil [Federal Land Development Authority (FELDA) Sahabat]. The result from the study conducted in MPOB, Bangi showed that the total weevil life cycle and development period ranged from 1-14 days, whereby the eggs hatched in 0-1 day, formation of larva I was around 1-3 days, larva II around 2-10 days, larva III around 4-12 days, pupae around 6-14 days and adult weevil around 8-14 days, without any significant differences between the four populations in different soil types from different plantations. About 80 per cent of male and female weevils can live an average of 33 and 32 days, respectively. However, there were no significant differences in longevity between male and female adults. Meanwhile, the morphological size measured differed significantly among the life stages between the four weevil populations. Overall, there was a slight variation, however, there was no significant difference in the life cycle, development period and longevity between the four weevil populations in different types of soil from different plantations in Malaysia. Keywords: Life history, longevity, morphological size, soil types, agriculture.

Influence of Water Table and Peat Thickness on Dissolved Organic Carbon of Tropical Peat Soil with Sulfidic Substratum from Central Kalimantan, Indonesia

Peatlands are important due to their high carbon storage, their role in suppressing climate change processes, and their importance for local and global communities’ livelihood. Large amounts of organic carbon pools in peatlands can be released into the environment as gaseous emitted carbon and lost through waterways (fluvial). The carbon released through the water stream consists of organic and inorganic forms and is partly in the form of CO2 and CH4 gases. The organic form consists of dissolved organic carbon (DOC) and particulate organic carbon, where DOC is the most dominant organic carbon in water sourced from peatlands. This research's objectives were to study the DOC concentration of peat water resulting from the hydrological condition's difference and the peat thickness overlaying the sulfidic substratum. The study was carried out in the Pangkoh area of Pulang Pisau district of Central Kalimantan. Peat water is taken on PVC pipes installed on each plot representing different peat thicknesses (deep, moderate, and shallow peat) at a depth of 25, 50, 100, 150, 200, and 250 cm from the soil surface. The water sampling was conducted on the peak wet season, during the transition from wet season to dry season and during the peak dry season. The results showed that DOC was influenced by peat thickness, depth of sulfidic material, and groundwater level. The release of DOC is higher from the deep peat than from the thin and moderate peat. The difference in DOC concentration between peat thickness is also related to the electrical conductivity of the peat water. The results showed a negative correlation between electrical conductivity and DOC concentration. The negative correlation was significant in the observation of the rainy and dry seasons, while in the transitional season, it was not significant.

Temperature and organic carbon quality control the anaerobic carbon mineralization in peat profiles via modulating microbes: A case study of Changbai Mountain

Peatlands account for a significant fraction of the global carbon stock. However, the complex interplay of abiotic and biotic factors governing anaerobic carbon mineralization in response to warming remains unclear. In this study, peat sediments were collected from a typical northern peatland-Changbai Mountain to investigate the behavior and mechanism of anaerobic carbon mineralization in response to depth (0–200 cm) and temperature (5 °C, 15 °C and 20 °C), by integrating geochemical and microbial analysis. Several indices including humification indexes (HI), aromaticity, and water extractable organic carbon (WEOC) components were applied to evaluate carbon quality, while 16S rRNA sequencing was used to measure microbial composition. Regardless of temperature, degradations of carbon quality and associated reduction in microbial abundance as well as diversity resulted in a decrease in anaerobic carbon mineralization (both CO2 and CH4) towards greater depth. Warming either from 5 °C to 15 °C or 20 °C significantly increased anaerobic carbon mineralization in all depth profiles by improving carbon availability. Enhanced carbon availabilities were mediated by the change in microbial composition (p < 0.01) and an increase in metabolic activities, which was particularly evident in the enhanced β-glucosidase activity and microbial collaborations. A remarkable increase of over 10-fold in the relative abundance of the Geothrix genus was observed under warming. Overall, warming resulted in an enhanced contribution of CH4 emission and a higher ratio of hydrogenotrophic methanogenesis, as evidenced by carbon isotope fractionation factors. In addition, deep peat soils (>100 cm) with recalcitrant carbon demonstrated greater temperature sensitivity (Q10: ∼2.0) than shallow peat soils (Q10:∼1.2) when temperature increased from 15 °C to 20 °C. The findings of this study have significantly deepened our understanding for mechanisms of carbon quality and microbe-driven anaerobic carbon mineralization in peatlands under global warming.

Exploration and culture of arbuscular mycorrhizal fungi from wild sago

The sago palm (Metroxylon sagu Rottb.) contains significant potential for carbohydrates. When harvested, the plant produces more than 300kg of dry starch per plant. Arbuscular mycorrhizal fungi (AMF, Glomeromycota) are known to often form symbiotic associations with the majority of higher plants, but there are limited studies on their interaction with Sago. Therefore, this study aims to obtain information on the presence of arbuscular mycorrhizal fungi from the rhizosphere of sago palms as well as to prepare pure cultures of the dominant species. Samples were collected from the test plant’s rhizosphere by exploring the West Papua region with a shallow peat area as a base. The soil bulk density in the region was 0.11-0.20 g cm−3 with a low pH (H2O) of 4.1. At the initial stage, a trapping culture was prepared from the rhizosphere soil sample, and a pure culture was then made from the dominant spore using telang (Clitoria ternatea.L) as the host. The observation results of spore morphology revealed that they belonged to Acaulosporaceae, Gigasporaceae, and Glomeraceae. The low abundance and diversity of AMF were caused by abiotic factors, including soil physicochemical properties.

Microbial Communities of Peaty Permafrost Tundra Soils along the Gradient of Environmental Conditions and Anthropogenic Disturbance in Pechora River Delta in the Eastern European Arctic

Microbial communities play crucial roles in the global carbon cycle, particularly in peatland and tundra ecosystems experiencing climate change. The latest IPCC assessments highlight the anthropogenic changes in the Arctic peatlands and their consequences due to global climate change. These disturbances could trigger permafrost degradation and intensification of the biogeochemical processes resulting in greenhouse gas formation. In this study, we describe the variation in diversity and composition of soil microbial communities from shallow peat tundra sites with different anthropogenic loads and applied restoration interventions in the landscape of remnant fragments of terraces in the Pechora River delta, the Russian Arctic, Nenets Autonomous Okrug. The molecular approaches, including quantitative real-time PCR and high-throughput Illumina sequencing of 16S RNA and ITS, were applied to examine the bacterial and fungal communities in the soil samples. Anthropogenic disturbance leads to a significant decrease in the representation of Acidobacteria and Verrucomicrobia, while the proportion and diversity of Proteobacteria increase. Fungal communities in undisturbed sites may be characterized as monodominant, and anthropogenic impact increases the fungal diversity. Only the verrucomicrobial methanotrophs Methyloacifiphilaceae were found in the undisturbed sites, but proteobacterial methanotrophs Methylobacterium-Methylorubrum, as well as different methylotrophs affiliated with Methylophilaceae, and Beijerinckiaceae (Methylorosula), were detected in disturbed sites.

Characteristics of Peat with Different Depths in Supporting Growth and Productivity of Oil Palm

The potential for oil palm production on peatlands is very diverse; different types of peat, maturity, and depth significantly influence yields. This study aims to determine the characteristics of peat with different depths in supporting the growth and productivity of oil palm. The research was conducted at the PT Kaswari Unggul Palm Oil Plantation in Jambi Province using laboratory surveys and test methods. Observations done were Plant height, Number of Fresh Fruit Bunches (FFB), Stem Circumference, FFB Weight, Midrib Length, Palm Oil Productivity, Light Intensity. Soil analysis were available-P, total-Fe-, total N, organic-C and CEC, pH, Al-exchange, total-K, Soil Moisture, and Peat Maturity. In shallow peat, the soil is more completely decomposed and provides nutrients that can be absorbed by plants so that plants grow better. The results showed that the shallow peat has a maturity level of sapric peat (very ripe) and peat in hemic maturity (slightly mature). Also, the depth of peat will affect the value of total-N, pH, available-P, and K-exchange and does not affect organic-C, total-Fe, CEC, and Al-exchange. Moreover, the growth and production of oil palm on shallow peat were better than on deep peat.

Effect of bionanomaterials and Shorea balangeran compost application on the growth of peat rice (Oryza sativa L.) in peatland

Peatlands are acidic with low fertility. Conversely, shallow peat can become a food source for local communities, thus requiring soil amendment to improve productivity and sustainable use. One of the ways is by applying bionanomaterials (BNMs) derived from oil palm empty fruit bunch (OPEFB) and oil palm trunk (OPT) as well as Shorea balangeran compost as an indigenous shallow peat species. This study aims to analyze the effect of BNMs on rice germination in a laboratory (in vitro) and rice growth in the greenhouse (in vivo). The experimental design used a completely random design of 2 factors, namely rice varieties and BNMs (activated, non-activated OPEFB, OPT lignocellulose, and non-activated OPT, respectively, at doses of 1%, 3%, 5%, 7%) (in vitro) as well as rice varieties and ameliorant (BNMs, compost) (in vivo). The results showed that BNMs affected average sprout height and germination rates on a laboratory scale. BNMs derived from an activated OPEFB rate of 5% produce the highest percentage of plant life (49.2%) (in vivo). Meanwhile, S. balangeran compost affects the percent of plant life (45.8%). The combination of BNMs and compost application can be applied to peat rice to increase productivity and maintain peatlands’ fertility.

The Effect of Atmospheric Pressure Variations on the Suprapermafrost Groundwater Level and Runoff of Small Rivers in the Anadyr Lowlands, Northeast Russia

The present-day models of the hydrological regime of soils and river basins do not include a hypothesis regarding the effect of atmospheric pressure on hydrological processes (baric effect), which is assumed negligible. However, their manifestations are likely, considering the mechanical and hydrophysical properties of shallow peat-bog soils (plasticity and elasticity, high moisture-retention capacity, the ability to swell and shrink) and the important role of undecomposed plant remains. The effect of atmospheric pressure variations on level changes in a suprapermafrost aquifer was detected using field and laboratory experiments in shallow peat and peaty tundra soils in the Anadyr Lowlands, Northeast Russia. One can see this effect in the runoff regime of 1st–4th orders streams. The manifestations of this phenomenon can differ, and in particular, they can be directed oppositely. The changes in the level and storage of suprapermafrost gravitational water could be caused only by synchronous (in phase opposition) changes in capillary water fringe above the groundwater table. To explain the observed phenomena, a conceptual model is developed based on the analysis of the balance of forces and water balance in a system of elastic capillaries. Not being complete and perfect, the model reproduces qualitatively the main observed cases of the response to air pressure changes, proving the effect itself, and suggests the likely localization of its mechanisms. A shallow suprapermafrost groundwater table in contact with the peat bottom, as well as incomplete (below the full moisture capacity) water saturation of peat soil horizons, appear to be circumstances of the baric effect on tundra shallow subsurface aquifers. Favorable conditions for the baric effect in a soil profile include a high elasticity of peat-soil matrix, high and variable values of porosity and water yield of peat and moss cover, and, at the catchment scale, a high proportion of coverage by these types of soils. A full-scale study of a mechanism of baric effect on a suprapermafrost tundra aquifer requires numerous laboratory and field experiments, that must be much better equipped than presented in our study. It is also welcomed alternative hypotheses regarding the aquifer water level response to changes in air pressure if the observed macroscopic effects at any alternative occurrence could be quite similar.

Homogeneous selection is stronger for fungi in deeper peat than in shallow peat in the low-temperature fens of China

Peatlands have accumulated enormous amounts of carbon over millennia, and climate changes threatens the release of this carbon into the atmosphere. Fungi are crucial drivers of global carbon cycling because they are the principal decomposer of organic matter in peatlands. However, the fungal community composition and ecological preferences in peat remain unclear, which restricts our ability to evaluate the role of the fungal community in peat biogeochemical functions. We investigated 54 soils from 6 low-temperature peatlands across China to fill this knowledge gap. The peat was divided into above-water table (AWT) and below-water table (BWT) layers based on the water table fluctuation. We investigated fungal community assembly processes and drivers for each peat layer. The results showed that fungal communities differed significantly among peat layers. The relative abundance of symbiotrophs was significantly higher in the AWT (17.4%) than in the BWT (9.0%), while the abundances of yeast and litter saprotrophs were obviously lower in the AWT than in the BWT. Our results revealed that the assemblage of both fungal taxonomic and phylogenetic communities was mainly governed by stochastic processes in both AWT (87.8%) and BWT (58.6%) layers. However, in the BWT, the relative importance of deterministic processes (28.4%) significantly increased, indicating a potential deterministic environmental selection induced by permanently anaerobic condition. Mean annual precipitation and mean annual temperature were the most critical drives for the assemblage of the fungal community in the BWT. These observations collectively indicate that fungal community assembly is depth-dependent, implying different community assembly mechanisms and ecological functions along the peat profile. These findings highlight the importance of climate driven deep peat fungal community composition assemblages and suggest the potential to project the changes in fungal diversity with ongoing climate change.

Perspectives on the changing properties of peat soils used for agriculture: the case of Talio Hulu Village

Rice fields in Talio Hulu Village, located in the Swamp Irrigation Area (SIA) Block B Pangkoh I, Pandih Batu District, Pulang Pisau Regency, Central Kalimantan is cleared peatlands which replanted with rice afters being abandoned for years. This paper is a review of peatland research and development in Talio Hulu Village. This paper aims to provide an overview of sequential changes of peat soils since its opening in 1983, being developed by planting rice and secondary crops, subsequently abandoned, and afterwards managed and replanted in 2020. Soil chemical properties and fertility in 1987 showed that the top layer (0-30 cm) and below (>30 cm) were very acidic (pH 3.3-3.9); C-organic 36% and 53%; N total 2.3% and 1.2%; low base cation exchange capacity, and P2O5 1.4 mg kg−1 and 0.43 mg kg−1, then the plant showed less than optimal growth. The identification of chemical properties and fertility of the top and bottom layers of the soil after rice development in 1993 showed improvements, including: decreasing soil acidity with pH H2O 3.4-4.4 and 3.3-3.7; C-organic decreased to 11.46% and 54.52%; N total 0.33-1.11% and 0.48-1.53%; P2O5 7-100 mg kg−1 and 10-15 mg kg−1. Rice yields reached 0.3-2.0 t ha−1 for local rice varieties and 0.2-2.4 t ha−1 for high-yielding varieties. The low yield of rice indicated the poor growth of rice plants measured from the high amount of empty grain. From the survey in 2020, we identified 80% of rice fields were categorized as peat and 20% as shallow peat (peat layer <100 cm). After land remediation, soil acidity decreased (pH increased) at pH 4.11 and 4.47, C-organic decreased by 34.89 % and 42.48%, P-available increased to 17.90 mg kg−1 and 22.88 mg kg−1, and no more deep peat was found. Meanwhile, rice productivity increased to 1.55-6.31 t ha−1 or 3.27 t ha−1 an average.

Variations in peat soil properties at the west coast of Sumatra Island

Peat in coastal areas has different characteristics compared to peat in inland areas because coastal peat usually has high DHL, pyrite, marine sandy substratum, and maturity which is generally classified as hemic to sapric. These variants in soil characteristics drive peculiarity in its management. For this reason, a more detailed information about the characteristics is needed to allow sustainable management and utilization. A total of 78 peat soil samples from 20 peat soil profiles taken over west coast of Sumatra was studied and analyzed for their physical and chemical properties. Field observations were made using a peat auger to determine thickness and maturity, substratum, presence of pyrite, and others. Results showed that peat thickness varied from shallow (50-100 cm), medium (100-200 cm), to very deep (>700 cm); peat situated closer to the coast generally has shallow peat depth. Peat soil in coastal areas contained a mineral soil substrate with a sand content of >70%. It was found that soil had a hemic maturity level and a very acidic to acidic pH value (pH 2.5-5.4). The P2O5 content extracted by 25% HCl varied from low to moderate, while K2O content of 25% HCl extraction was very low. Cations K, Na, and Ca were very low to very high, while Mg spanned from very low to high. Based on its thickness, 25% of peatland were not suitable (Nrc) for general agriculture uses because of >300 cm thickness. Therefore, it is necessary to improve soil fertility and water management in several places.

The interaction between vegetation types and intensities of freeze-thaw cycles during the autumn freezing affected in-situ soil N2O emissions in the permafrost peatlands of the Great Hinggan Mountains, Northeastern China

Soil freeze-thaw cycles are associated with nitrous oxide (N 2 O) emissions, and climate warming changes the freeze-thaw process of permafrost and delays the starting period of soil freezing. However, it remains unclear how freeze-thaw cycles of the autumn freezing period ( AFT ) affect in-situ soil N 2 O emissions in permafrost peatlands. Therefore, we used static chamber-GC techniques to measure N 2 O emissions in the three permafrost peatlands [ Calamagrostis angustifolia peatland ( CAP ), Larix gmelina-Sphagnum peatland ( LGS ), and Eriophorum vaginatum peatland ( EVP )] during the AFT of 2019. Results showed that the three types of permafrost peatlands presented the conversion of in-situ soil N 2 O source/sink process during the mild, moderate, and severe intensities of AFT . The intensities of AFT significantly affected N 2 O fluxes, and vegetation types showed no significant effect. However, the interaction between vegetation types and intensities of AFT significantly influenced the N 2 O fluxes in the three permafrost peatlands. During the mild intensity, N 2 O fluxes were driven by surface temperature and NO 3 − -N content in the shallow peat layer; during the moderate intensity, N 2 O fluxes were driven by soil moisture content in the shallow peat layer; during the severe intensity, N 2 O fluxes were driven by the soil NH 4 + -N content and DOC content. These results demonstrated that the interaction of vegetation types and intensities of AFT affected in-situ N 2 O emissions in the permafrost peatlands. This work could make up for the study blank of in-situ N 2 O emissions during the AFT in the permafrost peatlands of the Great Hinggan Mountains, Northeast China. • The intensities of autumn freeze-thaw cycles significantly affected N 2 O fluxes. • Vegetation types of permafrost peatland has no significant effect on N 2 O fluxes. • Interaction of vegetation types and freeze-thaw intensities affected N 2 O emissions. • N 2 O fluxes were driven by temperature, NO 3 − -N, moisture, NH 4 + -N and DOC content.

Effects of land use on the hydrologic regime, vegetation, and hydraulic conductivity of peatlands in the central Peruvian Andes

The vegetation, geographic distribution, and pastoralist uses of peatlands in the central Andes have been extensively studied over the past 20 years. However, little information exists to characterize the hydrologic processes that support these groundwater-dependent ecosystems or the hydrologic alterations occurring due to human activities or climate changes. This lack of information significantly limits our understanding of how the central Andean Puna, one of the world's most threatened ecoregions, may be altered by increasing temperature and water extraction for human use. In addition, these peatlands provide critical pasture for native and domestic livestock and carbon storage, but overgrazing is an important modifier of their ecological trajectories.We analyzed three groundwater-fed fen peatlands with differing hydrologic regimes, annual precipitation, land use, and vegetation composition. Water table depth was a key factor significantly contributing to differences in soil hydraulic conductivity (p < 0.05) and vegetation composition (p < 0.05). Saturated hydraulic conductivity (K) varied from 0.57 m day−1 to 0.03 m day−1 for the horizontal component (Kh) and 0.07 to 0.002 m day−1 for the vertical component (Kv). The principal differences in K were in the seasonally unsaturated upper soil layers at 0–75 cm depth. The annual deepening in the water table and Distichia muscoides dominance drive the variability in K for these layers. Those drivers were themselves correlated but can individually modify K, increasing the decomposition rate and porosity (WT deepening) and altering the initial peat structure (D. muscoides dominance). Three vegetation communities were identified, one in sites with the deepest water tables, the lowest hydraulic conductivities, and dominance of Werneria pygmaea and Plantago rigida. The second community, dominated by bunch grasses in the genus Calamagrostis, occurred in areas with the most variable water table and medium hydraulic conductivity. The third community occurred in the most hydrologically stable areas, with the shallowest water table, highest hydraulic conductivities, and was dominated by Distichia muscoides. The study peatlands appear to have originated as the third community – groundwater-supported fens dominated by Distichia muscoides cushion and pool communities. However, modern hydrologic changes caused by human land uses and climate variability have caused a divergence in the vegetation, and in the more disturbed sites created higher decomposition rates in the shallow peat layers, and differences in soil structure.

Arbuscular Mycorrhizal Communities in the Roots of Sago Palm in Mineral and Shallow Peat Soils

Communities of arbuscular mycorrhizal fungi (AMF) in plant roots improve host plant growth. In this study, AMF communities in the roots of the sago palm (Metroxylon sagu Rottb.) were investigated in mineral soil (MS) and shallow peat soil (SPS) in Sarawak, Malaysia. MS exhibited lower moisture content (MS, 38.1; SPS, 79.8%), higher pH (H2O) (MS, 4.6; SPS, 4.1), higher soil bulk density (MS, 1.03; SPS, 0.20 g cm−3), and higher nitrogen content (MS, 16.9; SPS, 2.7 kg m−3) than SPS at the same soil depth, while the phosphorus (P) content (Bray II) (MS, 1.6; SPS, 1.9 g P2O5 m−3) was similar. The AMF colonization rate was significantly lower in SPS (39.2 ± 12.5%) than in MS (73.2 ± 4.6%). The higher number of AMF operational taxonomic units (OTUs) was detected by amplicon sequencing of the partial small-subunit rRNA gene (MS, 78; SPS, 50). A neighbor-joining tree of obtained OTUs revealed that they belonged to Acaulosporaceae, Ambisporaceae, Claroideoglomeraceae, Gigasporaceae, and Glomeraceae. The lower abundance and diversity of AMF in SPS are possibly caused by abiotic factors, including soil physicochemical properties. Glomus and Acaulospora species detected in SPS might have strong tolerance against acidity and high soil moisture content.

The performance of paludiculture commodities at different peat depths in Central Kalimantan

Paludiculture is one of the alternative efforts to restore degraded peatland. It involves rewetting, revegetation and revitalization of local livelihood. This research evaluated three paludiculture demonstration plots at Central Kalimantan, one in the shallow peat of Pilang village and two plots in the deep peat of Tumbang Nusa village. The plots were evaluated in terms of the plant’s growth, productivity, commodities introduced and environmental monitoring, including water table, soil physical and chemical properties, carbon stocks and CO2 emission. The results showed that the three plots were categorized as “compromised” paludiculture plots because some of the commodities were not local peatland species. Belangeran (Shorea balangeran) and horticultural plant species such as rambutan (Nephelium lappaceum) and pineapple (Ananas comosus) showed good growth performance. Liberica coffee (Coffea liberica) was not suitable for deep peat due to its low survival rate and poor growth. The result also showed that soil peat characteristics of the sites were still in good condition; however, the impact of peatland utilization should have been monitored to support land-use sustainability. Moreover, stingless bee cultivation and vegetables could become potential commodities to be developed in shallow and deep peatland.