The microbial diversity and structure in peatland forest in Indonesia

The microbial community structure and function under forest in tropical peatlands are poorly understood. In this study, we investigated the microbial community structure and diversity in natural peat swamp forest soil, disturbed peat soil and mineral soil in Central Kalimantan, Indonesia, using 454 pyrosequencing. The results showed that the natural peat soil had the greatest fungal species richness (Chao1), which was significantly (p < .05) larger than that in the other two soils. Community structure of both fungi and bacteria in natural peat soil differed significantly from that in the disturbed peat soil (p = .039 and p = .045, respectively). Ascomycota (40.5%) was the most abundant phylum across the three soils followed by Basidiomycota (18.8%), Zygomycota (<0.1%) and Glomeromycota (<0.1%). The linear discriminant analysis with effect size (LEfSe) showed that Ascomycota (p < .05) and genus Gliocephalotrichum (p < .05) dominated in natural peat soil. Functionally, pathotrophs were more abundant in disturbed peat soil (p < .05). Proteobacteria (43.8%) were the most abundant phylum followed by Acidobacteria (32.6%), Actinobacteria (9.8%), Planctomycetes (1.7%). Methylocystis, Telmatospirillum, Syntrophobacter, Sorangium and Opitutus were the more abundant genera in disturbed peat soil, whereas Nevskia and Schlesneria were more abundant in mineral soil and natural peat soil, respectively. The natural peat forest soil supported a more diverse microbiology; however, the land use of such a soil can change its microbial community structure. The results provide evidence that the disturbance of tropical peat land could lead to the introduction and spread of a large number of fungal diseases     

土壤有机碳对沼渣或牛粪施用后温室气体排放潜力的影响—盆栽试验结果

A change in the European Union energy policy has markedly promoted the expansion of biogas production.Consequently,large amounts of nutrient-rich residues are being used as organic fertilizers.In this study,a pot experiment was conducted to simulate the high-risk situation of enhanced greenhouse gas (GHG) emissions following organic fertilizer application in energy maize cultivation.We hypothesized that cattle slurry application enhanced CO2 and N2O fluxes compared to biogas digestate because of the overall higher carbon (C) and nitrogen (N) input,and that higher levels of CO2 and N2O emissions could be expected by increasing soil organic C (SOC) and N contents.Biogas digestate and cattle slurry,at a rate of 150 kg NH4+-N ha-1,were incorporated into 3 soil types with low,medium,and high SOC contents (Cambisol,Mollic Gleysol,and Sapric Histosol,termed Clow,Cmedium,and Chigh,respectively).The GHG exchange (CO2,CH4,and N2O) was measured on 5 replicates over a period of 22 d using the closed chamber technique.The application of cattle slurry resulted in significantly higher CO2 and N2O fluxes compared to the application of biogas digestate.No differences were observed in CH4 exchange,which was close to zero for all treatments.Significantly higher CO2 emissions were observed in Chigh compared to the other two soil types,whereas the highest N2O emissions were observed in Cmedium.Thus,the results demonstrate the importance of soil type-adapted fertilization with respect to changing soil physical and environmental conditions.     

Carbon stocks and carbon fluxes from a 10‐year prescribed burning chronosequence on a UK blanket peat

Prescribed burning is a common land management technique in many areas of the UK uplands. However, concern has been expressed at the impact of this management practice on carbon stocks and fluxes found in the carbon‐rich peat soils that underlie many of these areas. This study measured both carbon stocks and carbon fluxes from a chronosequence of prescribed burn sites in northern England. A range of carbon parameters were measured including above ground biomass and carbon stocks; net ecosystem exchange (NEE), net ecosystem respiration (R_eco) and photosynthesis (P_g) from closed chamber methods; and particulate organic carbon (POC). Analysis of the CO₂ data showed that burning was a significant factor in measured CO₂ readings but that other factors such as month of sampling explained a greater proportion of the variation in the data. Carbon budget results showed that whereas all the plots were net sources of carbon, the most recent burn scars were smaller sources of carbon compared with the older burn scars, suggesting that burning of Calluna‐dominated landscapes leads to an ‘avoided loss’ of carbon. However, this management intervention did not lead to a transition to a carbon sink and that for carbon purposes, active peat‐forming conditions are desirable.     

The impact of beaver dam removal on the chemical properties of water in drainage ditches in peatland forests

ABSTRACT

Despite near-extinction in the nineteenth century, after efficient restoration measures the population of Eurasian beaver (Castor fiber L.) in Latvia currently is viable and growing. While the ecological effect of the species on water quality and biodiversity is generally positive, the high number of animals in production forests often creates challenges for management. Drainage ditches are among the most favoured habitats of beavers resulting in flooded stands, reduced tree growth and economical losses. The aim of the study was to evaluate the chemical properties of water in forest drainage ditches, affected by beaver activity, and their changes after the dam removal. Chemical composition of surface water in ditches was analysed in sampling points above dam, below dam and in the ditch itself after removal of the dam; results compared to pristine beaver site nearby on a small stream. Results did not show significant differences between concentrations above and below dams. After removal of the dams, significant increase in DOC, N-NO₃ ^-, N-NH₄ ⁺ and TSS concentrations and significant decrease in TP concentrations were observed in some of the sites. Observed concentrations of all measured parameters were significantly lower in pristine beaver site than in beaver sites on drainage ditches.     

Carbon stocks and sequestration potentials of agricultural soils in the federal state of Baden‐Württemberg,SW Germany

Soil organic carbon (SOC) inventories are important tools for studying the effects of land‐use and climate change and evaluating climate‐change policies. A detailed inventory of SOC in the agricultural soils of the federal state of Baden‐Württemberg was therefore prepared based on the highest‐resolution geo‐referenced soil, land‐use, and climate data (BÜK200 inventory). In order to estimate the quality of different approaches, C inventories of the region were also prepared based on data from the National Inventory Report (UBA, 2003) and by applying the IPCC (1997) method to the two data sets. Finally, the BÜK200 inventory was used to estimate potentials of no‐tillage agriculture (NT) and peatland restoration to contribute to C sequestration and greenhouse‐gas (GHG)‐emission mitigation since both measures are discussed in this context. Scenario assumptions were change to NT on 40% of the cropland and restoration of 50% of cultivated peatlands within 20 years. On average, grasslands contained 9.5 kg C m^–2 to 0.3 m depth as compared to only 6.0 kg C m^–2 under cropland, indicating strong land‐use effects. The SOC content depended strongly on waterlogging and elevation, thus reflecting reduced C mineralization under aquic moisture regimes and low temperatures. Comparison of the BÜK200 inventory with the approach used for UBA (2003) showed high inconsistencies due to map resolution and SOC contents, whereas the IPCC method led to fairly good agreements. Results on the simulated effects of NT and peatland restoration suggested that 5%–14% of total agricultural GHG emissions could be abated with NT whereas peat restoration appeared to have a minor mitigation potential (0.2%–2.7%) because the total area of cultivated organic soils was too small to have larger impact.     

Regeneration result of excavator-mounted rototiller in direct seeding of Scots pine on forestry-drained peatland

The need to regenerate peatland forests is expected to increase in the near future in Finland due to harvest of large amounts of peatlands drained during the 1950s and 1960s. In anticipation of this, a new type of excavator-mounted rototiller for soil scarification in peatlands has been developed in Finland to improve the moisture conditions of the seedbed by mixing the ground vegetation, raw humus layer, and peat. The regeneration result of the new rototiller was compared with traditional patch scarification (i.e. scalping) in direct seeding of Scots pine in three forestry-drained peatland sites in eastern Finland. After two growing seasons, rototilling offered no advantage over scalping in terms of the number of established seedlings, probability of empty patches, or seedling height. Seedling establishment was on average higher on scalping (10%) than on rototilling (8%). The main problem in rototilling may have been the loose and porous structure of the seedbed resulting in drought and frost damages.     

欧洲和北美地区退化泥炭地修复技术与借鉴

泥炭地是重要的自然湿地类型，具有固碳、水文调节、生物多样性维护等多种生态系统服务功能。受侵蚀、火灾等自然灾害以及排水疏干、过度放牧和基础建设等强烈的人为干扰，全球泥炭地面积不断缩减，成为全球气候变化背景下的碳源。文中从水文修复、植被修复和生态监测与评估等方面，综述了欧洲和北美国家退化泥炭地修复技术研究进展，结合若尔盖湿地修复技术现状进行了研究展望，旨在为我国高原退化湿地的生态修复提供参考。     

The effect of peatland drainage and rewetting (ditch blocking) on extracellular enzyme activities and water chemistry

Extensive areas of European peatlands have been drained by digging ditches in an attempt to improve the land, resulting in increased carbon dioxide fluxes to the atmosphere and enhanced fluvial dissolved organic carbon (DOC) concentrations. Numerous peatland restoration projects have been initiated which aim to raise water tables by ditch blocking, thus reversing drainage‐induced carbon losses. It has been suggested that extracellular hydrolase and phenol oxidase enzymes are partly responsible for controlling peatland carbon dynamics and that these enzymes are affected by environmental change. The aim of this study was to investigate how drainage and ditch blocking affect enzyme activities and water chemistry in a Welsh blanket bog, and to study the relationship between enzyme activity and water chemistry. A comparison of a drained and undrained site showed that the drained site had higher phenol oxidase and hydrolase activities, and lower concentrations of phenolic compounds which inhibit hydrolase enzymes. Ditch blocking had little impact upon enzyme activities; although hydrolase activities were lowered 4–9 months after restoration, the only significant difference was for arylsulphatase. Finally, we noted a negative correlation between β‐glucosidase activity and DOC concentrations, and a positive correlation between arylsulphatase activity and sulphate concentration. Phenol oxidase activity was negatively correlated with DOC concentrations in pore water, but for ditch water phenol oxidase correlated negatively with the ratio of phenolics to DOC. Our results imply that drainage could exacerbate gaseous and fluvial carbon losses and that peatland restoration may not reverse the effects, at least in the short term.     

Determination of Poly-β-hydroxyalkanoate in Peat

Poly-β-hydroxyalkanoate (PHA) is a prokaryotic energy reserve material that has been used as an indicator of environmental stress in aquatic bacteria. The following technique has been used to quantify PHA in peatland microorganisms. Peat samples were dried, digested in sulphuric acid to convert PHA into crotonic acid, and the resulting acid determined using organic acid high performance liquid chromatography (HPLC) and ultraviolet (UV) detection at 214 nm. This technique is suggested to have potential value as an indicator of environmental stress on peatland microorganisms, such as that caused by summer drought, or changes in soil nutrient availability, which are predicted consequences of climatic change.