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Peatlands, constituting over half of terrestrial wetland ecosystems across the globe, hold critical ecological significance and are large stores of carbon (C). Irish oceanic raised bogs are a rare peatland ecosystem offering numerous ecosystem services, including C storage, biodiversity support and water regulation. However, they have been degraded over the centuries due to artificial drainage, followed by peat extraction, afforestation and agriculture. This has an overall negative impact on the functioning of peatlands, shifting them from a moderate C sink to a large C source. Recognizing the importance of these ecosystems, efforts are underway for conservation (rewetting and rehabilitation), while accurately accounting for C stock and greenhouse gas (GHG) emissions. However, the implementation of these efforts requires accurate identification and mapping of artificial drainage ditches. This study utilized very high‐resolution (25 cm) aerial imagery, and a deep learning (U‐Net) approach to map the visible artificial drainage (unobstructed by vegetation or infill) in raised bogs at a national scale. The results show that artificial drainage is widespread, with ~20 000 km of drains mapped. The overall accuracy of the model was 80% on an independent testing dataset. The data were also used to derive the Fracditch which was 0.03 (fraction of artificial drainage on industrial peat extraction sites). This is lower than IPCC Tier 1 Fracditch and can aid in IPCC Tier 2 reporting for Ireland. This is the first study to map drains with diverse sizes and patterns on Irish‐raised bogs using optical aerial imagery and deep learning methods. The map will serve as an important baseline dataset for evaluating the artificial drainage ditch conditions. It will prove useful for sustainable management, conservation and refined estimations of GHG emissions. The model's capacity for generalization implies its potential in mapping artificial drains in peatlands at a regional and global scale, thereby enhancing the comprehension of the global effects of artificial drainage ditches on peatlands. [ABSTRACT FROM AUTHOR]

Tailwater recovery system (TWR) sediment quality in Mississippi, USA, was evaluated seasonally within the storage reservoir and drainage ditch system from 2016 to 2019 for pesticide contamination, effects and bioavailability to Hyalella azteca (Saussure). Sediment bioassays (28-day) measured H. azteca survival and growth and tissue residue risks from sediment pesticide exposure. Sediment pesticide contamination comprised six current-use herbicides, three current-use insecticides, three legacy insecticides and one metabolite (p,p'-DDE). Sediment clomazone, bifenthrin and ΣDDT concentrations were greatest in drainage ditch sites during summer and fall. H. azteca tissue pesticide residues comprised three current-use herbicides and insecticides, as well as two legacy insecticides. Tissue residue clomazone, Ζ-cypermethrin and ΣDDT concentrations were greatest in drainage ditch sites during fall and winter. H. azteca survival and growth varied seasonally and spatially with lowest survival during fall and winter and lowest survival in the storage reservoir relative to drainage ditch sites during winter. Growth decreased during winter and spring with lowest growth in drainage ditches relative to the storage reservoir during spring. Patterns of associated survival and growth with tissue pesticide residues indicate increased risk during fall in TWR and where system water flows mobilise sediment pesticides increasing the risk of ecological impairment. [ABSTRACT FROM AUTHOR]

(1) Background: The understory planting of Chinese herbal medicine is a common soil and water conservation farming measure, and this approach makes full use of the natural conditions of the understory. However, a large number of studies on soil erosion have focused on the simulation of natural indoor conditions, and there are very few investigations on soil erosion caused by understory planting in the field. This study aims to investigate the effects of different slopes on soil and water and nitrogen–phosphorus nutrient loss from understory planting of Gastrodia elata Bl by changing the vegetation structure and soil structure of forest land. (2) Methods: To reveal the nitrogen and phosphorus loss and flow and sediment characteristics of the understory planting of Gastrodia elata Bl, runoff plots were set up in a field, and three surface slopes (5°, 15°, and 20°) were designed to collect runoff sediments and compare the soil and water loss between the natural slopes and those with Gastrodia elata Bl. This provides a basis for the restoration of vegetation cover and the enhancement of soil fertility. (3) Results: The total loss of soil, water, nitrogen, and phosphorus in the forested land with Gastrodia elata Bl increased significantly compared with that in the natural forested land, and the greater the slope was, the greater the loss was. (4) Conclusions: Planting Gastrodia elata Bl should be avoided in areas with steep slopes and serious soil erosion. However, some soil and water conservation engineering measures can be taken, such as the construction of retaining walls, drainage ditches, etc., to minimize the scouring and erosion of soil by rainwater. [ABSTRACT FROM AUTHOR]

Drainage ditches play a key role in the conservation of fragmented landscapes by providing refuge sites and secondary habitats for many terrestrial and aquatic organisms across various taxa. Species richness of ditches can exceed that of adjacent natural habitats, but here, we looked further and assessed the role of drainage ditches in shaping the community structure of true bugs aiming to better estimate ditches' conservation value from the point of their species and trait composition. We tested the effects of the ditch substrate (saline, sandy or fen), landscape matrix (agrarian or grassland) and vegetation (species richness of all plants and invasive plants, and abundance of woody plants) on the true bug communities of 60 drainage ditches in the lowland of East-Central Europe. We found that substrate and landscape matrix contributed the most in determining true bug communities. Based on species composition, different substrates and landscape matrix types had distinct communities, but the trait composition showed differentiation according to the landscape matrix in saline habitats only. The trait composition in true bug communities was more diverse in grassland ditches than in agrarian ones, which hosted more habitat generalists associated with invasive vegetation. We concluded that a pronounced gradient in habitat stress, originating in substrate salinity and aridity, causes the differentiation of the true bug communities based on their trait composition. Additionally, intense habitat stress increases the number of habitat specialists and the conservation value of a drainage ditch. [ABSTRACT FROM AUTHOR]

Colloidal phosphorus (P), defined as P associated with particles within the size range from 1 to 1000 nm, is an often-neglected yet significant component of waterborne P, posing global water quality concerns. This comprehensive review elucidates the various sources and concentrations of colloidal P across diverse water environments, highlighting its prominence in agricultural wastewater, with mean concentrations of 122.6 μg/L (n = 437), compared to groundwater (52.3 μg/L, n = 26), surface freshwater (22.3 μg/L, n = 246), and seawater (5.4 μg/L, n = 36). Correlations between physicochemical water parameters, elemental composition and colloidal P concentrations are obtained, and the dominant subfractions and chemical species of colloidal P in water are identified. Notably from chemical speciation, colloidal organic P exhibits dominance in surface freshwater with higher abundance relative to colloidal inorganic P. Meanwhile, statistical analyses on physical fractions of colloidal P indicate that fine subfractions prevail in agricultural wastewater. Accordingly, this review investigates potential transformation mechanisms of colloidal P due to physical and chemical behaviors such as aggregation, desorption, and photodegradation, influenced by factors such as pH, salinity, coexisting elements and UV irradiation. Drawing on these insights, we propose eco-friendly mitigation strategies, including constructed wetlands or ecological drainage ditches and UV irradiation, aimed at treating water (especially agricultural wastewater) with elevated colloidal P levels. This review not only enhances our understanding of the occurrence and transformations of colloidal P, but also offers practical guidance for its effective environmental management. [ABSTRACT FROM AUTHOR]

[Objective] The aims of this study are to explore the feasibility of using GF-1 satellite data to retrieve the concentration of dissolved nitrous oxide (N2O) in water so as to provide an effective way to realize low-cost and high-efficiency real-time monitoring of water quality. Methods The 1st and 5th drainage ditches in Qingtongxia Irrigation District of Ningxia were selected as the research objects, and the reflectance and water quality parameters of GF-1 satellite image band, which were highly correlated with the concentration of dissolved N2O in the drainage ditches, were selected as independent variables, and the optimal combination of independent variables was determined by optimal subset screening method. Multiple linear regression, BP neural network and support vector machine models were respectively constructed to predict and compare the concentration of dissolved N2O in water. [Results] The water temperature (T) and dissolved organic carbon (DOC) were the main factors affecting the concentration of dissolved N2O in water, and satellite bands such as near infrared (NIR) were significantly correlated with the variation trend of dissolved N2O concentration in water. When the independent variable including 7 factors such as T and NIR. the model had the best prediction effect. Among the three models, the R of BP neural network model was 0.64. which had the highest prediction accuracy. [Conclusion] There is a complex correlation between GF-1 satellite data and water quality parameters and dissolved N2O concentration in water bodies, and BP neural network can use GF-1 satellite data to retrieve dissolved N2O concentration in water bodies with high accuracy. [ABSTRACT FROM AUTHOR]

The Somerset Levels and Moors, UK is an area of high conservation value, including nationally and internationally protected wetland sites. Duckweed (Lemna) mats in the Somerset Levels and Moors are increasingly common and are an indication of hyper-eutrophication. Duckweed mats can contribute to increased management burdens and decreases in biodiversity. Research suggests duckweed will thrive in temperate regions as the climate warms. This study investigated the impact of climate warming and eutrophication on duckweed growth in the Somerset Levels and Moors using a previously published model to simulate duckweed growth from the years of 2020–2080. Simulated local climate change projections and adjustments in actual nitrogen and phosphorus levels were used to estimate changes in biomass. Using the simulated data, the model predicted an 83% increase in biomass from the 2020's to the 2070's if nutrients do not change. In order to offset the impact of climate change on duckweed biomass, nutrient levels will need to decrease by more than 50% by 2080. Further changes to management practices will likely be necessary to restore healthy ecological function and biodiversity in the area. [ABSTRACT FROM AUTHOR]

Introduction: Agricultural drainage ditches are essential for maintaining flow efficiency and are often managed by brushing (i.e., vegetation clearing along ditch banks) and dredging. These maintenance practices not only impact flow but also the ditches' capacity to process and assimilate agricultural chemicals. However, the influence of ditch management on microbial activities, essential in processing and transforming these contaminants, remains underexplored. Methods: We conducted a four-year surface water sampling campaign in two long-established (over 40 years) agricultural drainage ditches situated in eastern Ontario, Canada. One drainage ditch underwent intensive bank brushing and channel dredging, while the other remained unmanaged. We assessed the impact of these contrasting ditch management practices on the diversity and compositional structure of surface water microbiome communities, with a particular focus on the distribution of genes associated with nitrogen (N) cycling, using shotgun metagenomics sequencing and an assembly-based metagenome approach. Results and discussion: From 117 surface water samples, we reconstructed 157 metagenome-assembled genomes (MAGs), predominantly from the Patescibacteria superphylum. Brushing alone, conducted about 10 months prior to dredging, had an insignificant impact on the aquatic microbial community. However, dredging led to a significant reduction in community diversity and abundance of genes affiliated with denitrification, dissimilatory nitrate reduction to ammonia, and complete nitrification through comammox. Ditch management resulted in noticeable shifts in the microbial community, evidenced by the enrichment of taxa in Polaromonas, Emticicia, Flectobacillus, and Patescibacteria in the water of the managed ditch sites. The metagenomes of these taxa harbor genes involved in various nitrogen biotransformation pathways. Interestingly, following dredging, the levels of ammonia and ammonium, nitrite, and total Kjeldahl N in the managed ditch did not increase, but significantly decreased; likely due to ditch substrate removal and potentially increased flow efficiency and dilution. Being one of the few studies conducted to date, this study provided unique insights into the consequences of drainage ditch management on freshwater microbiomes involved in N cycling. [ABSTRACT FROM AUTHOR]

Ski tourism's popularity is driving a rise in the number of ski resorts. This study aims to present the impact of ski infrastructure on soil erosion processes in the example from a small catchment in the Gubałowskie Foothills in southern Poland, where landscape changes before (since 1879) and after the construction of the ski station (2007) are presented. The analyses of changes in flow accumulation, slope morphometry, and drainage ditches were conducted in the test area. Quantitative analyses were performed using repeated DEMs derived from aerial LiDAR survey and detailed geodetic measurements, complemented by geomorphological mapping done in the field. The study has revealed that the ski infrastructure has not only directly transformed the hillslope by flattening and constructing escarpments (up to 3 m high) but has also created alternating patterns of erosion and accumulation. In the test area, the drainage ditch was poorly designed. It was filled with materials (0.1–0.5 m), and two new outlets formed. The escarpment of the analyzed ski run has been diminished by 0.5 m. An alluvial fan (0.1–0.22 m thick) has developed on the flattened surface below the escarpment with drainage ditch outlets. This fan is eroded by subsurface flow that creates a piping system. The gully below the alluvial fan has retreated upslope, accelerated by subsurface erosion. This study enables the presentation of hillslope adjustments and processes in response to the new conditions caused by ski infrastructure. Such results may support more effective land management in regions changed by ski infrastructure. [ABSTRACT FROM AUTHOR]

Accurately characterizing rainfall runoff processes in plain farmland, especially at the plot scale with significant micro-topographic features, has presented challenges. Integrated surface–subsurface flow models with high-precision surface flow modules are appropriate tools, yet open-source versions are rare. To address this gap, we proposed an open-source integrated surface–subsurface flow model called the FullSWOF-Plain model, in which the one-dimensional subsurface module Hydrus-1D was integrated with a modified two-dimensional surface water flow module (FullSWOF-2D) using the sequential head method. Various experimental scenarios were simulated to validate the model's performance, including two outflow cases (i.e., 1D and 2D) without infiltration, a classical one-dimensional infiltration case, and two typical rainfall events at the experimental field. The results demonstrate the accuracy of this proposed model, with the Nash–Sutcliffe efficiency (NSE) of the simulated discharge exceeding 0.90 in the experimental field case and the root mean squared error (RMSE) values for soil moisture at five depths consistently below 0.03 cm3/cm3. However, we observed a lag in the simulated response time of soil moisture due to the neglect of preferential flow. The micro-topography significantly influenced ponding time and ponding areas. Lower local terrain normally experienced earlier surface ponding. Scattered surface ponding water first occurred in the ditch and followed in the relatively low areas in the main field. The concentration process of surface runoff exhibited hierarchical characteristics, with the drainage ditch contributing the most discharge initially, followed by the connection of scattered puddles in the main field, draining excess surface water to the ditch through rills. This quantitative study sheds light on the impact of micro-topography on surface runoff in plain farmland areas. [ABSTRACT FROM AUTHOR]

In agriculture‐dominated watersheds where natural drainage is poor, agricultural ditches (narrow engineered channels) and tile drains (perforated pipes) are widely employed to enhance surface and subsurface drainage, respectively. Despite their relatively small scale, these features exert substantial control over the hydro‐biogeochemical function of watersheds and their effects need to be represented in the models. We introduce a novel strategy to incorporate the effects of artificial agricultural drainage into a fully distributed basin‐scale integrated surface‐subsurface hydrology models. In our approach, narrow agriculture ditches for surface drainage are resolved efficiently using ditch‐aligned computational meshes that are hydrologically conditioned to ensure connectivity in the stream/ditch network. For tile drainage in the subsurface, we use the physically based Hooghoudt's drainage equation as a subgrid model and route the water drained through tiles to the nearest ditch. Without site‐specific calibration, this model reproduced observed streamflow in the Portage River Watershed (>1,000 km2) as recorded by a USGS gauge with good accuracy (normalized KGE = 0.81) and outperformed a calibrated SWAT model (normalized KGE = 0.68). Numerical experiments confirm that artificial drainage reduces surface inundations and effectively controls the water table. At the watershed scale, artificial drainage increases baseflow but has little effect on watershed discharges above the 90th percentile. The strong physical underpinnings and reduced need for calibration allow us to study the impacts of artificial drainage on distributed hydrological response in terms of fluxes and states and provide a platform for investigating watershed‐scale nutrient transport. Key Points: Novel strategy is developed to incorporate effects of artificial drainage into fully distributed basin‐scale integrated hydrology modelWithout site‐specific calibration, our model reproduced observed streamflow well and outperformed calibrated SWAT modelNumerical experiments reveal the effects of surface and surface drainage on various hydrological states and fluxes [ABSTRACT FROM AUTHOR]

Climate warming and associated accelerated permafrost thaw in the Arctic lead to a shift in landscape patterns, hydrologic conditions, and release of carbon. In this context, the lateral transport of carbon and shifts therein following thaw remain poorly understood. Crucial hydrologic factors affecting the lateral distribution of carbon include the depth of the saturated zone above the permafrost table with respect to changes in water table and thaw depth and the connectivity of water-saturated zones. Landscape conditions are expected to change in the future due to rising temperatures and polygonal or flat floodplain Arctic tundra areas in various states of degradation; hydrologic conditions will also change. This study is focused on an experimental site near Chersky, northeast Siberia, where a drainage ditch was constructed in 2004 to simulate landscape degradation features that result in drier soil conditions and channeled water flow. We compared water levels and thaw depths in the drained area (dry soil conditions) with those in an adjacent control area (wet soil conditions). We also identified the sources of water at the site via stable water isotope analysis. We found substantial spatiotemporal changes in the water conditions at the drained site: (i) lower water tables resulting in drier soil conditions, (ii) quicker water flow through drier areas, (iii) larger saturation zones in wetter areas, and (iv) a higher proportion of permafrost meltwater in the liquid phase towards the end of the growing season. These findings suggest decreased lateral connectivity throughout the drained area. Shifts in hydraulic connectivity in combination with a shift in vegetation abundance and water sources may impact carbon sources and sinks as well as transport pathways. Identifying lateral transport patterns in areas with degrading permafrost is therefore crucial. [ABSTRACT FROM AUTHOR]

Urea-based fertilizers applied to crop fields can enter the surface waters of adjacent agricultural drainage ditches and contribute to the nitrogen (N) loading in nearby watersheds. Management practices applied in drainage ditches promote N removal by the bacterial communities, but little is known about the impacts of excess urea fertilizer from crop fields on the bacterial diversity in these ditches. In 2017, sediments from drainage ditches next to corn and soybean fields were sampled to determine if fertilizer application and high urea-N concentrations alters bacterial diversity and urease gene abundances. A mesocosm experiment was paired with a field study to determine which bacterial groups respond to high urea-N concentrations. The bacterial diversity in the ditch next to corn fields was significantly different from the other site. The bacterial orders of Rhizobiales, Bacteroidales, Acidobacteriales, Burkholderiales, and Anaerolineales were most abundant in the ditch next to corn and increased after the addition of urea-N (0.5 mg N L−1) during the mesocosm experiment. The results of our study suggests that urea-N concentrations >0.07 mg N L−1, which are higher than concentrations associated with downstream harmful algal blooms, can lead to shifts in the bacterial communities of agricultural drainage ditches. [ABSTRACT FROM AUTHOR]

Ludwigia ravenii (G1G2) is a wetland-obligate perennial, endemic to the Atlantic Coastal Plain. The species appears to be relegated to roadside ditches and ruts, and is under review for federal listing. The objectives of this study were to quantitatively assess biotic and abiotic habitat characteristics of extant populations and augment knowledge of the species ecology. Two congeners were selected for comparative analysis: L. alternifolia and L. pilosa. Over two field seasons, data were collected from 108 1 m2 quadrats and variable length transects across the species range. All 17 element occurrences of L. ravenii on record during the 2020--2021 sampling period were visited and 15 (nplots=62) were sampled. Forty-six plots at 14 sites were collectively sampled for the target congeners (L. alternifolia, nplots=27; L. pilosa, nplots=19). Variables assessed included: physical ditch dimensions, aspect, elevation, canopy cover, abiotic and vegetative cover, and edaphic variables (nutrient composition and pH). Data were visualized using NMS and PCA, and analyzed using ANOVA and post-hoc tests. Only PCA showed distinct clustering of quadrats of L. ravenii along soil fertility gradients. Quadrats of L. ravenii exhibited median values compared to congeners in many measured variables, including canopy cover, species richness, and Shannon's diversity index. Quadrats of L. ravenii differed most strongly from congeners by more acidic mean soil pH (4.68±0.05). Although no single species emerged as an ideal indicator, the combination of L. linearis and Kellochloa verrucosa was found highly suggestive of suitable habitat for L. ravenii. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Although an unintended aircraft landing on water (referred to as ditching) is a rare event, the potential for occupant injury/fatality increases immediately following the event due to adverse conditions. However, to date, few studies have addressed the subject. Herein, ditching events and post-ditching survival were investigated. METHODS: Ditchings (1982--2022) in the United States were identified from the National Transportation Safety Board database. Occupant injury severity, aircraft type, pilot experience, flight conditions, and number of occupants were extracted. Poisson distribution, the Chi-squared test (2-tailed), Mann-Whitney U test, and Kruskal-Wallis one-way analysis of variance were employed. RESULTS: A total of 96 ditchings were identified. A systematic survey was hampered by the lack of a standardized reporting matrix in the reports. In total, 77 reports were included in the analysis. Across all ditchings, 128 of 169 (76%) occupants survived ditching and were rescued. Importantly, the initial ditching event was survived by 95% of all occupants. However, 32 (19%) occupants died post-ditching by drowning (21/32 cases) or for undetermined reasons. Considering probability per ditching event, in 26 (34%) of all ditchings, one or more occupants was/were fatally injured. DISCUSSION: Initial survival of the emergency ditching is high. Drowning was the leading cause of death after ditching and reduced the overall survival to 76%. Further investigation is needed to identify risk factors for fatal outcomes and/or improve probability of survival after ditching. [ABSTRACT FROM AUTHOR]

Open dump landfills are recognised as potential sources of heavy metal (HM) contamination. Their migration to the wider environment is largely controlled by their speciation; and in this study, results from sequential extraction, pH values and organic matter contents in soils around an open dump landfill and sediments in a leachate collection ditch were investigated in order to study the attenuation processes that lead to a decrease in HM mobility. The results revealed that Cu and Zn leached from the landfill were largely retained by sediments in the collection ditch and mostly bound to organic fraction. A simple mass balance suggested that, in comparison to other sources, HM accumulation in soils that resulted from the landfill was relatively low for Cu and relatively high for Zn. The concentrations observed were within safe limits according to the Thai standard for non-residential soil. This study showed that a leachate collection ditch plays an important role in minimising HM migration. Monitoring and further studies on fate and migration pathways of pollutants from open dump landfills, in particular to those underlain by different geologic settings to our study are needed to develop cost-effective measures to prevent/minimise the effect of landfill leachate and ensure that the environment surrounding landfill sites is safe. [ABSTRACT FROM AUTHOR]

The global issue of ecological ditches being poor in removing nitrogen and phosphorus under cold winter temperatures has been identified. This study introduced three types of biochar (reed, rice, and corn) into ecological ditch sediments via two application methods: rhizosphere and mixed addition. The purpose was to explore how these methods affect the removal of nitrogen and phosphorus, as well as their influences on microbial communities in sediments. The results indicated that the addition of biochar to ecological ditches significantly enhanced the removal of nitrogen and phosphorus. Among the three types of biochar, the mixed addition of corn biochar yielded the greatest results, achieving removal rates of 77.1% for total nitrogen (TN), 93.3% for NH4+-N, and 90.3% for total phosphorus (TP). The growth of Vallisneria natans was greatly improved by the mixed addition method, resulting in an average increase of 154%. This improvement was superior to the rhizosphere addition group, which led to a growth increase of 125%. In comparison, the control group (CK) showed a decrease of 4.8% in growth. Different methods of biochar addition resulted in changes in the physicochemical properties and stoichiometry of the plants. Microbial analyses showed that the addition of biochar reduced the diversity and abundance of the substrate microbial community. [ABSTRACT FROM AUTHOR]

Debris flow can cause damage only when its discharge exceeds the drainage capacity of the prevention engineering. At present, most rainfall thresholds for debris flows mainly focus on the initiation of debris flow and do not adequately consider the magnitude and drainage measures of debris flows. These thresholds are likely to initiate numerous warnings that may not be related to hazardous processes. This study proposes a method for calculating the rainfall threshold that is related to a defined level of debris flow magnitude, over which certain damage may be caused. This method is constructed by using the transient rainfall infiltration analysis slope stability model (TRIGRS) and the fluid dynamics process simulation model (MassFlow). We first use the TRIGRS model to analyze slope stability in the study area and obtain the distribution of unstable slopes under different rainfall conditions. Afterward, the MassFlow model is employed to simulate the movement process of unstable slope units and to predict the depositional processes at the mouth of the catchment. Lastly a rainfall threshold is constructed by statistically analyzing the rainfall conditions that cause debris flows flushing out of the given drainage ditch. This method is useful to predict debris flow events of a hazardous magnitude, especially for areas with limited historical observational data. [ABSTRACT FROM AUTHOR]

Soil carbon content and stability are primarily influenced by the stabilization of particulate organic matter (POM) and mineral-associated organic matter (MAOM). Despite extensive research on the stabilization processes of POM and MAOM carbon components under various land-use types, the investigation into stabilization processes of soil carbon remains limited in saline–alkali soils. Therefore, we collected soil samples from different positions of saline–alkali drainage ditches at four reclamation times (the first, seventh, fifteenth, and thirtieth year) to determine their carbon content and physicochemical properties. Moreover, POM and MAOM fractions were separated from soil samples, and Fourier transform infrared spectra (FTIR) were used to investigate changes in their chemical composition. The results showed that with increasing reclamation time, the soil total carbon and soil organic carbon (SOC) contents significantly increased from 14 to 15 and 2.9 to 5.5 g kg−1, respectively. In contrast, soil inorganic carbon content significantly decreased from 11 to 9.6 g kg−1. Notably, the changes in soil carbon components following the increasing reclamation time were primarily observed in the furrow sole at a depth of 20–40 cm. While the SOC content of the POM fraction (SOCPOM) decreased significantly, the SOC content of the MAOM fraction (SOCMAOM) increased significantly. These alterations were largely dominated by drainage processes after reclamation instead of a possible conversion from SOCPOM to SOCMAOM. FTIR results revealed that MAOM was greatly influenced by the reclamation time more than POM was, but the change in both POM and MAOM contributed to an increase in soil carbon stability. Our findings will deepen the comprehension of soil carbon stabilization processes in saline–alkali drainage ditches after reclamation and offer a research framework to investigate the stability processes of soil carbon components via alterations in POM and MAOM fractions. [ABSTRACT FROM AUTHOR]

Bois noir (BN) is a grapevine yellows disease associated with 'Candidatus Phytoplasma (Ca. P.) solani' that is transmitted to grapevines by the planthopper Hyalesthes obsoletus Signoret which uses herbaceous plants such as Urtica dioica as a pathogen reservoir. Urtica dioica is often widespread along ditches bordering vineyards, and a gradient in decreasing BN symptomatic grapevines is observed from the vineyard edges facing these ditches. In two vineyards in north-eastern Italy, over eight or seven years, the ditch bordering one edge of each vineyard was divided into two sections; in one of these, U. dioica was chemically weeded in April, while the other one remained untreated. The impact of chemical weeding on the spatial distribution of both H. obsoletus captures and newly BN symptomatic grapevines was assessed. The reduction in H. obsoletus captures in the vineyard sector facing the section of the ditch subjected to weeding corresponded to a decrease in newly symptomatic grapevines. These findings demonstrated that nettle removal from areas surrounding vineyards can effectively control BN. [ABSTRACT FROM AUTHOR]

The article discusses the first recorded sighting of the Palearctic Aphanisticus congener Saunders, 1875 (Coleoptera: Buprestidae) in the Western Hemisphere. The discovery was made through an image posted on the insect identification website, BugGuide, and confirmed by an expert in the genus. Additional specimens were found in Texas, suggesting a wider distribution than previously thought. The article also highlights the differences between A. congener and Aphanisticus cochinchinae seminulum, another species in the genus. The establishment of two Aphanisticus species in the US is a mystery, and further research is needed to understand their dispersal and plant host range. [Extracted from the article]

Forest roadside ditch lines capture and redirect road runoff and typically have erosion control treatments installed therein. Existing methods used to determine the effectiveness of roadside ditch line erosion control treatments estimate fixed fractional reductions in sediment yield. However, fixed fractional reductions do not describe dependence on any measurable physical property of treatment, climate, and the environment. Here, we use additional flow roughness induced by erosion control treatments as a metric that can be used as the basis of estimating treatment effectiveness in varying contexts. We investigate its utility in small‐scale field experiments in western Washington. We measured the physical characteristics of each ditch (e.g., shape, soil texture, and slope) and flow velocities and sediment concentrations for each treatment under multiple experimental discharges. We then used the concept of shear stress partitioning to relate sediment yield from the ditch line erosion treatments to grain shear stress, which is a function of flow roughness (Manning's n) of the respective treatment. We found that (1) a given erosion control treatment produced consistent Manning's n values across multiple replications and sites, with a bare ditch (no treatment) yielding the lowest roughness (n = 0.05) and a densely wattled ditch yielding the highest roughness (n = 0.75); (2) sediment load and calculated grain shear stress data yielded a single positive relationship when data from each experiment were combined, which suggests the effect of additional roughness on grain shear stress is a main driver in the reduction of ditch line sediment load; and (3) in our dataset, fractional erosion reduction had a variable and nonlinear sensitivity to low flow rates (99% of observed flows) for lower roughnesses. Our results demonstrate how additional flow roughness can be used as a general metric to help evaluate the effectiveness of ditch line erosion control treatments for a variety of physical conditions. [ABSTRACT FROM AUTHOR]

Forest management in drained forested peatlands can negatively affect water quality due to the increase in exports of organic matter and nutrients. Therefore, new methods to alleviate this impact are needed. In laboratory conditions, biochar has been shown to be a strong sorbent of organic and inorganic nutrients due to its high surface area and ion‐exchange capacity. However, evidence of the adsorption capacity in field conditions is lacking. Here, we studied the water purification performance of two different biochar feedstocks (wood‐ and garden residue‐based) in a 10‐day laboratory experiment where we incubated biochar with runoff water collected from drainage ditches in clear‐cut peatland forests. We measured changes in pH and concentrations of inorganic phosphorus (PO4), total dissolved nitrogen (TDN), and dissolved organic carbon (DOC). The biochar with the best adsorbent capacity in the laboratory experiment was then tested in field conditions in a replicated catchment‐scale experiment, where both clear‐cutting and ditch cleaning were performed. We determined the nutrient concentration of water at the inlet and outlet of biochar filters placed in outflow ditches of four catchments. We found that under laboratory conditions wood‐based biochar efficiently adsorbed TDN and DOC, however, it released PO4. Furthermore, we found that the biochar filters reduced TDN and DOC concentration in field conditions. However, the percentage decrease in concentration was dependent on the initial concentrations of nutrients in the water and could be considered low. Moreover, we found that the biochar in the filters increased in TN content over the course of the experiment. This suggests that a wood‐based biochar filter has the potential to be a water protection tool for reducing the export of nutrients from catchments with high nutrient concentration. And that the biochar from the ditches could be applied back to the regenerating forest catchment as a potential soil amendment, closing the nutrient cycle. [ABSTRACT FROM AUTHOR]

Community assembly can change over time following variations in connectivity among habitats. Previous studies have demonstrated the influence of seasonal pulse floods on community structures by facilitating species dispersal, but the effects of short‐term flash floods have been poorly investigated. We investigated fish community structures before and after a short‐term flood in drainage ditches of paddy fields in the Kita River basin, Japan. The study sites were classified into three connectivity types, "Transient" (connected only during the flood, with a temporally disappearing vertical gap between drainage ditches and downstream rivers), "Connected" (always connected, without the vertical gap), and "Disconnected" (always not connected, with the vertical gap). The abundance of Misgurnus anguillicaudatus, the only species that dispersed from paddy fields to drainage ditches, increased after the flood irrespective of the connectivity types, although the total abundance of the other species significantly increased after the flood only in the "Transient" sites. The dissimilarity of species composition between the (n − 1)‐th and n‐th surveys at each site was consistently low in the "Connected" and "Disconnected" sites, whereas it rose just after the flood and gradually declined in the "Transient" sites. Species composition was significantly different among the connectivity types, indicating that some fish species need stable connectivity even during the non‐flood period. The results showed that the short‐term flood facilitated fish dispersal from paddy fields by the increased water discharge and that from downstream rivers by the temporary removal of vertical gap, emphasizing the importance of hydrological connectivity for biodiversity conservation in an agricultural landscape. [ABSTRACT FROM AUTHOR]

The installation of drainage ditches and removal of vegetation in preparation for vacuum harvesting alters the carbon dynamics of peatlands. However, we lack the measurements to understand the spatial distribution and environmental and substrate quality controls of carbon dioxide (CO2) and methane (CH4) emissions, as well as how these factors change over the 20–30 year extraction period. For three summers, we measured CO2 and CH4 emissions using the closed chamber method at three actively extracted peatlands near Drayton Valley, Alberta, ranging from 2 to 28 years since the start of extraction. Measurements were made in the ditches, and on segments of peat (fields) between adjacent ditches. Field emissions did not change with distance from ditches, likely due to the observed homogeneity of volumetric water content (VWC) and temperature across the fields. Understanding carbon dynamics in the ditches will be important, as they emitted on average two and 10 times, respectively, the amount of CO2 and CH4 per square meter of the fields. We found moderate to weak relationships between carbon emissions and soil temperature, VWC and ditch water level, though ditch emissions were significantly reduced when there was standing water present. Altering conventional site management, such as increasing ditch spacing, could substantially reduce CH4 emissions from the managed area. Emissions did not decrease with time since start of extraction. We suggest that Canadian emission factor calculations for land‐based emissions consider both peat quality variations among sites, and a site's extraction duration, which has been important in other studies. Plain Language Summary: Peat extraction for use in horticulture growing media contributes to peatland disturbance in Canada. In preparation for extraction, drainage ditches are dug to dry out the surface peat, and the vegetation is removed. These actions shift these sites from net stores of carbon, to net emitters, including the release of carbon dioxide (CO2) and methane (CH4), two powerful greenhouse gases. Few studies have quantified carbon emissions during the extraction period. To address this, we measured CO2 and CH4 emissions from actively extracted sites in Alberta, Canada for three summers, focusing on the spatial distribution and environmental controls of the emissions. We found that the drainage ditches were hotspots of emissions, emitting two and 10 times, respectively, the amount of CO2 and CH4 per meter squared of the non‐ditch portion of the site. We also found that emissions from the peat fields did not change with distance from the drainage ditches. More research is needed to better understand these water‐carbon interactions. Our work can support management practices that reduce these carbon emissions to help create a more sustainable industry. For example, we found that reducing the number of drainage ditches at a site could substantially reduce total methane emissions. Key Points: Drainage ditches emitted on average two and 10 times the amount of carbon dioxide and methane per square meter compared to the fieldsIncreasing drainage ditch spacing should be considered as a management strategy to substantially reduce CH4 emissionsLimited spatial variability in field carbon emissions, with no observed change with distance from the drainage ditches [ABSTRACT FROM AUTHOR]

Understanding the patterns of greenhouse gas emissions and the changes in pollution load in terrestrial freshwater systems is crucial for accurately assessing the global carbon cycle and overall greenhouse gas emissions. However, current research often focuses on wetlands and rivers, with few studies on agricultural drainage ditches, which are an important part of the agricultural ecosystem. Investigating the greenhouse gas emission patterns and pollution load changes in agricultural drainage ditches can help accurately assess the greenhouse effect of agricultural systems and improve fertilization measures in farmlands. This study explored the effects of nitrogen input and aeration on the pollution load and greenhouse gas emission processes in paddy field drainage ditches. The results showed that aeration significantly reduced the concentration of ammonium nitrogen (NH4+) in the water, decreased the emissions of nitrous oxide (N2O) and methane (CH4), and slightly increased the emission of carbon dioxide (CO2), resulting in an overall reduction of the global warming potential (GWP) by 34.02%. Nitrogen input significantly increased the concentration of ammonium nitrogen in the water, slightly reduced the emissions of N2O and CH4, and increased the CO2 emissions by 46.60%, thereby increasing the GWP by 15.24%. The drainage ditches reduced the pollution load in both the water and sediment, with the overall GWP downstream being 9.34% lower than upstream. [ABSTRACT FROM AUTHOR]

In view of the problems in operation process of fixed rake-type residual recycling component, such as poor individual profiling effect in film picking, easy clogging of the compound of films, soil and corn stubbles, high power consumption in film picking, and strong disturbance to seedbed soil, in this study, an operation model of intermittent filmpicking on full-film mulched double ditches was proposed and an intermittent film picking component was designed. The DEMMBD coupled algorithm was adopted for numerical simulation on the operation process of the intermittent film-picking component on full-film mulched double ditches, and a comparative analysis was carried out on the seedbed disturbance effect and resistance variation characteristics in film-picking by fixed and intermittent film-picking components. By taking the forward speed in film-picking, cam arrangement angle of the film-picking component and rotating speed of the cam shaft as independent variables, film-picking rate as the response value, a mathematical model between test factors and the film-picking rate was established, to explore the influence order of the factors on film-picking rate, and the optimal working parameters of the intermittent film-picking component were obtained as follows: the forward speed in film-picking was 2 km/h, cam arrangement angle was 180°, rotating speed of the cam shaft was 120 r/min. Under the optimal parameter combination, the average film-picking rate of the simulation test was 96.1%. Field test showed that, the average film-picking rate of the intermittent film-picking component was 95.6%, and 0.5% higher than that of the simulation test. The working condition of the sample machine was basically consistent with the simulation process, and can accurately represent the operation mechanism of intermittent film-picking on full-film mulched double ditches, showing that the established discrete element simulation model and its parameters were accurate and reasonable. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is a toxic contaminant that bioaccumulates in trophic chains in its organic form—methylmercury (MeHg). Hg methylation is driven by microorganisms in favourable conditions, stagnant water pools being among potential methylation hotspots. In the present study, we estimated the total Hg and MeHg concentrations in the sediments of water-filled management-induced terrain depressions (ruts, mounding pits and a partly functional drainage ditch) and in nearby undisturbed soil in six hemiboreal forest sites with organic-matter-rich soils in Latvia. Environmental samples were taken in the spring, summer and autumn of 2022. Furthermore, we evaluated the risks of element leaching from the depressions using high-resolution digital terrain models (DTM) and meteorological data. The results suggested a possible leaching of Hg in the past as THg concentrations in the sediments of the depressions were significantly lower than in the surrounding soil. Furthermore, significantly higher MeHg and %MeHg concentrations were found in the sediments than in the surrounding soil identifying the management-induced depressions as Hg methylation hotspots. Spatial analysis of the DTMs pointed to a very likely periodical leaching of elements from the depressions during high precipitation episodes as well as during snowmelts. Moreover, it was observed that ruts left by heavy machinery often channel surface runoff. [ABSTRACT FROM AUTHOR]

In this paper, the ditching performance of a seaplane model on calm water and a uniform water current coupled with wind was numerically investigated. The overset grid technique was applied to treat the large amplitude of the body motions of the seaplane without leading to mesh distortion. The effects of the initial velocity and the initial pitch angle on the slamming loads and motion responses were investigated for the seaplane's ditching on calm water. A good agreement with the experimental data on the velocity and angle was obtained. Besides ditching on calm water without the water current and wind, three more-complicated conditions were adopted, including the seaplane's ditching on calm water with wind, a water current without wind, and a water current coupled with wind. The accelerations and impact pressures of the seaplane can be influenced by the wind or current. Water splashing and overwashing could be observed during the water entry process, with water overtopping the seaplane head or nose and flowing over the body surface. It can be concluded that the relative motion between the water and the seaplane model should be carefully controlled to avoid possible damages caused by the occurrence of overwashing. [ABSTRACT FROM AUTHOR]

The core of the concept of nature-based solutions (NBS) is ecological protection, which is the same direction as China's double-carbon goal and has attracted much attention in China. Ecological ditch sewage treatment technology has been widely used in controlling agricultural non-point source pollution because of its advantages of high pollutant removal efficiency and low energy consumption. Suppose the NBS concept of sustainable management, restoration, and ecological protection is integrated into the research and development and application of ecological ditch technology. In that case, it can not only improve the effective removal of pollutants, achieve the purpose of recycling water resources and nutrient elements, but also realize economic, environmental, and social benefits. This paper describes the ecosystem service functions provided by ecological ditches in detail, evaluates their economic values through literatures review, so as to raise people's awareness of natural resource conservation and realize the sustainable management of ecological ditches. [ABSTRACT FROM AUTHOR]

Greenhouse gas (GHG) emissions from drained peatlands have been studied extensively. Considerably less attention has been paid to the emissions from the ditches used to drain peatlands. High within‐ditch GHG production and lateral inflow of GHGs may lead to ditches emitting considerable amounts of GHGs on the landscape scale.We quantified annual emissions of ebullitive and diffusive methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O) in 10 drainage ditches in intensively used temperate peatlands used for dairy farming, in The Netherlands. Additionally, we assessed water and sediment quality to determine proxies for emissions via the two emission pathways.The mean annual emissions from the studied ditches varied between 3.57 and 60.1 g CO2‐eq. m−2 day−1 (based on a global warming potential over a 100‐year timeframe), where CO2 contributed on average 43% (ranging between 1.9 and 22.0 g CO2 m−2 day−1) and diffusive CH4 contributed 16% (0.1–16.5 g CO2‐eq. m−2 day−1) to the total GHG emission. Ebullition of CH4 made up nearly half of the total GHG emission (40%, 1.3–40.9 g CO2‐eq. m−2 day−1). N2O emissions were mostly low. CO2 emissions were higher in winter months, while CH4 ebullition was higher during spring and summer. Diffusive CH4 emissions did not show a seasonal pattern.The mean emission factor, the estimate of average emissions per unit area (EF), for CH4 was 2144 kg CH4 ha−1 year−1, which is two times higher than the tier 1 EF reported by the IPCC (with underrepresented ebullition data), underlining the high variability of ditch emissions.Ditch emissions were also higher than the EF used for the surrounding drained peatlands indicating that ditch emissions can be important on the landscape scale and should be considered to be included in national greenhouse gas reporting. [ABSTRACT FROM AUTHOR]

The mobility of a snake robot is limited by factors such as its length, mass distribution, and torque output. To overcome these limitations, the cooperation between two snake robots can be an effective strategy, inspired by the hand-in-hand interaction of humans. In this article, the cooperative strategies for the double snake robots are presented to improve their mobility in some extreme environments. In order to achieve the force interaction between snake robots, we introduce a docking strategy, which enables them to cross ditches and climb slopes. We further study these cooperative strategies and demonstrate their effectiveness through experiments. The snake robots can dock with each other and cross ditches with a width of half the length of each robot. Additionally, the robot at the top of a slope can help the robot at the bottom climb a steep slope of 63.2 $ ^{\circ } $ ∘ , which would be difficult to achieve with a single snake robot. [ABSTRACT FROM AUTHOR]

To comprehensively comprehend the spatiotemporal variations in pollution load within the Sixth Drainage Ditch of the Ningxia Yellow River Diversion Irrigation Area, we employed the LOADEST model. We utilized daily flow data and concentrations of ammonia nitrogen (NH3-N), nitrate nitrogen (NO2-N), total nitrogen (TN), and total phosphorus (TP) to construct regression equations for the pollutant load at four distinct monitoring sections of the Sixth Drainage Ditch. The results unveiled an impressive range of correlation coefficients (R2) for the pollution load regression equations at the four monitoring sections, ranging from 72.42% to 94.4%. This indicates a strong fit for the pollution load regression equations, rendering them suitable for estimating the pollution load of the Sixth Drainage Ditch. Furthermore, the changing patterns of various pollutants in the same monitoring section exhibit a remarkable level of consistency. In each case, they initially experience an upward trajectory followed by a subsequent decrease. Notably, the total nitrogen (TN) load in the drainage area exceeds that of the total phosphorus (TP). The spatial distribution patterns of the total nitrogen (TN) and total phosphorus (TP) load within the Sixth Drainage Ditch exhibit a progressive increase from the upstream to downstream areas. Meanwhile, the spatial distribution characteristics of ammonia nitrogen (NH3-N) and nitrate nitrogen (NO2-N) follow a similar pattern of an initial increase followed by a decrease. [ABSTRACT FROM AUTHOR]

● The source and sink status of ditches and ponds was studied in an upland area in the Jinglinxi catchment, China.● Over the past 15 years, ditch length has increased by 32% and small pond number by 75%.● Ditches and ponds are important nutrient sinks in the dry season.● Retention of nutrients in ditches and ponds is up to 20%. As the common features of agroecosystems, ditches and ponds benefit the irrigation and drainage, as well as intercepting non-point source pollutants. However, most ditch-pond studies have been conducted in lowland areas. To test this source-sink assumption in upland areas, this study made observations on the ecological function of the ditch and pond system in a typical catchment in China. First, the changes in ponds in the catchment were analyzed using high-resolution remote sensing data. Then, the migration of agricultural pollutants in ditches and ponds were analyzed by field sampling and laboratory detection. The results showed that over the past 15 years the length of ditches in the catchment and the number of small ponds (< 500 m2) have increased by 32% and 75%, respectively. The rate of change in nutrient concentrations in the ditches and ponds were mostly from −20% to 20%, indicating ditches and ponds can be both sources and sinks for agricultural pollutants. Lastly, the contributing factors were explored and it was found that ditches and ponds are important sinks in dry season. However, during the rainy season, ditches and ponds become sources of pollutants, with the rapid drainage of ditches and the overflow of ponds in upland areas. The results of this study revealed that the ditches and ponds could be used for ecological engineering in upland catchments to balance drainage and intercept pollutants.

Odor emission from the soil of pesticide-contaminated sites is a prominent environmental problem in China, but there are very few researches about the component and spatial distribution of odorous substances in the soil of contaminated sites. In this paper, to investigate the odor pollution condition of an organophosphorus pesticide production site in a city of South China, the odor pollutants in the soil and soil gas were analyzed and the key odor–contributing substances were identified. Besides, the correlation between the concentrations of odorous substances in soil and soil gas was analyzed, and the measured results were compared with the predicted results by the linear model and DED model. An off-line soil gas sampling device was designed to collect the gas emitted from soil because the groundwater level in the site was too shallow to build a soil gas well. The key odor substances were screened from the detection results of soil gas via odor activity value (OAV) analysis, which revealed that the key odorous substances included benzene, ethylbenzene, ammonia, toluene, m,p-xylene, methyl sulfide, dimethyl disulfide, and formaldehyde. Furthermore, the spatial distribution of the odor substances in the soil of the pesticide-contaminated site was closely related to the layout and geologic structure of the site. The odor pollutants in soil were mainly distributed near the phosmet production workshop and the drainage ditch network. As for the deep distribution, the odorous substances were mainly enriched in the silty clay or clay layer (5.6–11 m), followed by the sludge layer (1–3.6 m). Finally, the predicted model (linear model and DED model) analysis suggested that the linear model was more suitable for predicting the concentration of odorous substances in the soil gas with the detection data of soil in this pesticide-contaminated site. [ABSTRACT FROM AUTHOR]

In a managed forest landscape, the high degree of human intervention has caused significant shifts in natural processes, and preservation of remaining natural ecosystem features is crucial to safeguard ecosystem functioning and support ecosystem services. While drainage ditches, subject to regular maintenance, are anthropogenically created and maintained infrastructure elements, they may still support diverse environmental conditions and provide habitats for a variety of plant species, including flowering plants important for pollinators. We assessed vegetation composition changes on recently reconstructed and unmanaged forest ditches and ditch edges in a commercial forest in Central Latvia in two surveys (one and five years after the ditch reconstruction). We used generalized linear mixed-effects models to analyze the impact of environmental variables on species richness and detrended correspondence analysis to analyze plant species composition. We found higher total plant species richness and insect-pollinated plant species richness along recently reconstructed ditches. The differences were mainly explained by better light availability beside reconstructed ditches. Anthropogenically created and managed ecosystems may support biodiversity and directly and indirectly contribute to the provision of different ecosystem services, including pollination. [ABSTRACT FROM AUTHOR]

Core Ideas: Dredging is a common maintenance practice in agricultural ditches and spoil management is a challenge for farmers.Farmers are concerned that application of sediments to fields poses a risk for redistribution of weed seed.Weeds germinated from ditch sediments in this study are controlled by commonly used herbicides. [ABSTRACT FROM AUTHOR]

Drainage water quality is a crucial factor reflecting the regime of agricultural non-point source pollution in irrigation districts and is closely related to land use, soil texture, cropping pattern, fertilization, and irrigation and drainage conditions. However, the response of drainage water quality to various natural and anthropogenic factors needs further exploration in irrigation districts affected by shallow groundwater table. Spatiotemporal patterns of chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), and ammonium nitrogen (NH4-N) were monitored and analyzed in ten agricultural drainage ditches in the arid region of China from 2011 to 2019. Spatially, water pollution in agricultural drainage ditches with small water quantity can be significantly exacerbated by urban sewage, whereas a large amount of agricultural drainage can effectively dilute the pollution of urban sewage. Severe soil salinization in the cropland increases the risk of water pollution due to easier losses of soil nutrient and organic matter. Soil salinization is a key factor in the crop distribution pattern based on the crop salt tolerance, and the maize/wheat field with a higher fertilizer application rate generally results in poorer drainage water quality. Temporally, for the agricultural drainage ditches, the monthly and annual COD, TP, TN, and NH4-N concentrations fluctuate inversely with drainage water quantity and are positively correlated with fertilizer application, among which the monthly COD concentration in drainage water has larger variation in severe salinized areas. There exist critical annual and monthly drainage amounts, above which the probabilities of higher concentrations of COD, TP, TN, and NH4-N reduce greatly. [ABSTRACT FROM AUTHOR]

Drainage for forestry has created ~ 1 million km of artificial waterways in Sweden, making it one of the largest human-induced environmental disturbances in the country. These extensive modifications of both peatland and mineral soil dominated landscapes still carry largely unknown, but potentially enormous environmental legacy effects. However, the consequences of contemporary ditch management strategies, such as hydrological restoration via ditch blocking or enhancing forest drainage to promote biomass production via ditch cleaning, on water resources and greenhouse gas (GHG) fluxes are unclear. To close the gap between science and management, we have developed a unique field research platform to experimentally evaluate key environmental strategies for drained northern landscapes with the aim to avoid further environmental degeneration. The Trollberget Experimental Area (TEA) includes replicated and controlled treatments applied at the catchment scale based on a BACI approach (before-after and control-impact). The treatments represent the dominant ecosystem types impacted by ditching in Sweden and the boreal zone: (1) rewetting of a drained peatland, (2) ditch cleaning in productive upland forests and (3) leaving these ditches unmanaged. Here we describe the TEA platform, report initial results, suggest ways forward for how to best manage this historical large-scale alteration of the boreal landscape, as well as warn against applying these treatments broadly before more long-term results are reported. [ABSTRACT FROM AUTHOR]

Segmentina nitida Müller 1774 is a freshwater snail which was formerly widespread throughout England and south Wales. Since the 1840s it has seen a rapid decline in its range which has been attributed to deteriorating water quality due to nutrient enrichment, lowering of water tables and over-management of the ditches in which it resides. S. nitida has therefore been identified as a UK Biodiversity Action Plan (UKBAP) priority species which recommends further research for its conservation. Here we have developed a Taqman based qPCR eDNA assay for the detection of S. nitida at the Stodmarsh National Nature Reserve and compared the results with a manual survey of the ditches at this location. 32 ditches were surveyed in November 2020 (22 at Stodmarsh) and February 2021 (10 outside the known range of S.nitida). Our eDNA analysis exhibited an observed percentage agreement of 84% with a kappa coefficient of agreement between manual and eDNA surveys of 0.56 (95% CI 0.22 to 0.92). Three ditches determined to be negative for S. nitida by eDNA analysis were manual survey positive, and a further two ditches that were negative by manual survey were positive by eDNA analysis revealing the potential for improved overall detection rates using a combination of manual and eDNA methodologies. eDNA analysis could therefore augment manual survey techniques for S. nitida as a relatively quick and inexpensive tool for collecting presence and distribution data that could be used to inform manual surveys and management of ditches. [ABSTRACT FROM AUTHOR]

Extensive drainage ditches are constructed to reduce soil salinity in reclaimed saline–alkali farmland, consequently forming plant growth hotspots and impacting soil carbon stocks therein. However, the investigation into changes in soil carbon stocks remains limited in these ditches. To address this, soil samples were collected from drainage ditches, which originated from the reclamation of saline–alkali farmland, at different reclamation years (the first, seventh, and fifteenth year). Moreover, fractions were separated from soil samples; a particle size separation method (particulate organic matter, POM; mineral–associated organic matter, MAOM) and a spatio–temporal substitution method were conducted to analyze the variations in soil carbon components and the underlying mechanisms. The results indicate that there were no significant variations in the contents and stocks of soil organic carbon (SOC) and soil inorganic carbon (SIC) following the increase in reclamation time. However, in the POM fraction, the SOC content (SOCPOM) and stock significantly decreased from 2.24 to 1.12 g kg−1 and from 19.02 to 12.71 Mg ha−1, respectively. Conversely, in the MAOM fraction, the SOC content (SOCMAOM) and stock significantly increased from 0.65 to 1.70 g kg−1 and from 5.30 to 12.27 Mg ha−1, respectively. The different changes in SOCPOM and SOCMAOM, as well as the result of the structural equation model, showed a possible transformation process from SOCPOM to SOCMAOM in the soil carbon pool under the driving force of reclamation time. The results in terms of the changes in soil carbon components demonstrate the stability rather than the stock of the soil carbon pool increase in coastal saline–alkali ditches following the excavation formation time. Although more long time series and direct evidence are needed, our findings further provide a case study for new knowledge about changes in the soil carbon pool within saline–alkali ditches and reveal the potential processes involved in the transformation of soil carbon components. [ABSTRACT FROM AUTHOR]