Marginal Sites Research Articles

Reduction potentials of chemical-synthetic pesticides – A case study using the example of an Eco-Scheme in southern Germany

Chemical-synthetic pesticides (CSPs) are associated with several negative environmental effects. The European Commission aims to reduce their use by 50% by 2030. This paper looks at the German Eco-Scheme, an agri-environmental payment scheme, for the foregoing of chemical-synthetic pesticides (CSPs) in arable crops for a one-year period. Using Baden-Württemberg in southern Germany as a case study, we investigated the suitability of the Eco-Scheme as a policy tool for CSP reduction. We used a field-based, georeferenced integrated land use model based on linear programming. Different payment levels for the Eco-Scheme were simulated. In addition, we analyzed the effect of labor availability, crop yield requirements, and market prices on Eco-Scheme implementation (uptake).The implementation potentials at €130/ha, the payment level in 2023, were limited and strongly dependent on market prices as well as potential food supply targets. The percentage decline in overall CSP use (measured in active substance mass) was even lower than the implementation in the percentage of acreage attributed to the Eco-Scheme. The implementation potentials were mainly observed on marginal sites. Higher simulated payment levels led to lower cost efficiency and dead weight losses. This trade-off between cost efficiency and effective reduction questions the suitability of the Eco-Scheme, at least for more substantial CSP reductions. To increase economic efficiency, we recommend differentiating payments based on abatement costs, for example on a crop-basis.

Productivity of hybrid sweetgum (Liquidambar formosana x styraciflua) plantations compared to native sweetgum (L. Styraciflua) in the Western Gulf Region of south-central U.S.

Sweetgum (Liquidambar styraciflua) is an excellent short-rotation woody crop species for producing hardwood pulp and biofuel feedstock on marginal sites. A recent development which may improve growth is the production of hybrid sweetgum (L. formosana x styraciflua) clones. We compared the productivity and attributes, e.g., wood specific gravity and stand growth, of operational plantations of hybrid sweetgum clones to improved native sweetgum half-sib families in 36 stands in Oklahoma, Texas, and Louisiana, U.S. The least square means (LSMean) of wood specific gravity was significantly greater for hybrids clones than the half-sibs (0.49 vs. 0.46 g/cm3), and the hybrid clones had less taper which necessitated developing genotype-specific volume and biomass equations. Despite having less fertilizer inputs on average, the hybrids had greater standing green stem biomass than the half-sibs at an age of 8.5 years (LSMean of 73.3 vs. 51.9 Mg/ha). The hybrids as a group also exhibited greater green biomass growth during the 2022 growing season when compared to the half-sibs at 8.5 years (LSMean of 15.8 vs. 11.4 Mg/ha/y). Therefore, the hybrids provide growth and wood quality advantages that may provide an opportunity to increase productivity and profitability of hardwood SRWC plantings.

Optimizing bioenergy sorghum productivity and nutrient removal in Illinois: Impact of nitrogen fertilization under diverse marginal conditions

Context or problemBioenergy sorghum (Sorghum bicolor L. Moench) is a promising crop for contributing to the United States bioenergy supply. However, the varying limitations of the marginal lands targeted for its cultivation present a management challenge. ObjectiveThis two-year study aimed to investigate how the limitations associated with marginal cropland impact the effects of nitrogen fertilization on the yield of bioenergy sorghum and the uptake of 11 macro- (N, P, K, Ca, Mg, and S) and micronutrients (Fe, Mn, Zn, Cu, and B). MethodsThe study contrasted prime cropland in central Illinois (Urbana) with three marginal cropland sites in southern (Ewing) and central Illinois (Fairbury and Pesotum). These marginal cropland sites are characterized by varying limitations, including low soil fertility (P and K limitations), leaching and erosion, and flooding, respectively. Four nitrogen rates (0, 56, 112, and 168 kg N ha−1) were tested under eight environments. ResultsThe average yields and ranges of sorghum biomass were 20.2 (17.0–23.2) Mg ha−1 in Urbana, 18.1 (13.1–19.8) Mg ha−1 in Ewing, 13.8 (9.0–17.3) Mg ha−1 in Fairbury, and 23.3 (14.6–33.0) Mg ha−1 in Pesotum. Optimal N rates were 56 N in Pesotum and 112 N in Urbana, Ewing, and Fairbury. Tissue macronutrient contents in Urbana were generally higher than in the marginal croplands, while micronutrient contents did not show discernible trends. Increasing N rate generally correlated with the macronutrient removal except in Ewing. ConclusionComparable sorghum biomass yields were observed between prime and marginal croplands (averaging 18.3 Mg ha−1), but optimal N rates varied between 56 N and 112 N. This suggests that yield gaps can be narrowed by applying the optimal N rates for the respective locations. However, increased removals of macronutrients, especially P and K, with increasing yields indicate the need to revise fertilizer recommendations, particularly for soils deficient in these nutrients. Implications or significanceOur study suggests that while sorghum production on marginal cropland is feasible, N management needs to be adapted to the unique limitations associated with various types of marginal cropland.

Geochemical characteristics and genesis of niobium–yttrium–fluorine granite pegmatite from Hmrat El Sorwhyia area, North Eastern Desert, Egypt

The granite pegmatites of Hmrat El Sorwhyia, situated in the northern Egyptian-Nubian Shield, are predominantly hosted within the central areas of syenogranitic bodies, with limited occurrences noted along the marginal sites. The Hmrat El Sorwhyia granitic pegmatites represent a notable example of rare-metal mineralisation. This study introduces novel bulk- rock compositions, including major, trace, and rare earth elements, to investigate and constrain the origin and mechanisms influencing the genesis of the Hmrat El Sorwhyia granitic pegmatites and their rare-metal mineralisation. The studied pegmatites exhibit diverse morphologies, featuring lenticular pockets that contain the highest radioelement concentrations. The maximum (equivalent uranium) eU value is 760 ppm while the maximum (equivalent thorium) eTh value is 5552 ppm. These pegmatites have granitic composition and peraluminous characteristics, indicative of A-type affinity associated with post-collisional tectonic settings, and are categorised as niobium–yttrium–fluorine-type pegmatites. The formation of granite pegmatites through fractional crystallisation during the late-stage magmatic processes involved the concentration of U, Th, rare earth elements, Zr, Y, and Nb. This concentration facilitated the crystallisation of thorite, uranothorite, columbite, cerianite, and zircon. Additionally, assimilation-fractional crystallisation mechanisms led to the exchange of accessory phases between successive injections of pegmatite and the surrounding wallrock, resulting in variable mineral concentrations. These open-system processes were responsible for the development of these pegmatites.

Early impacts of marginal land‐use transition to Miscanthus on soil quality and soil carbon storage across Europe

AbstractMiscanthus, a C4 perennial rhizomatous grass, is a low‐input energy crop suitable for marginal land, which cultivation can improve soil quality and promote soil organic carbon (SOC) sequestration. In this study, four promising Miscanthus hybrids were chosen to evaluate their short‐term potential, in six European marginal sites, to sequester SOC and improve physical, chemical, and biological soil quality in topsoil. Overall, no differences among Miscanthus hybrids were detected in terms of impacts on soil quality and SOC sequestration. SOC sequestration rate after 4 years was of +0.4 Mg C ha−1 year−1, but land‐use transition from former cropland or grassland showed contrasting SOC sequestration trajectories. In unfertilized marginal lands, cultivation of high‐yielding Miscanthus genotypes caused a depletion of K (−216 kg ha−1 year−1), followed by Ca (−56 kg ha−1 year−1), Mg (−102 kg ha−1 year−1) and to a lesser extent of N. On the contrary, the biological turnover of organic matter increased the available P content (+164 kg P2O5 ha−1 year−1). SOC content was identified as the main driver of changes in biological soil quality. High input of labile plant C stimulated an increment of microbial biomass and enzymatic activity. Here, a novel approach was applied to estimate C input to soil from different Miscanthus organs. Despite the high estimated plant C input to soil (0.98 Mg C ha−1 year−1), with significant differences among sites and Miscanthus hybrids, it was not identified as a driver of SOC sequestration. On the contrary, initial SOC and nutrients (N, P) content, as well as their elemental stoichiometric ratios with C, were the key factors controlling SOC dynamics. Introducing Miscanthus on marginal lands impacts positively soil biological quality over the short term, but targeted fertilization plans are needed to secure crop yield over the long term as well as the C sink capacity of this perennial cropping system.

Registration of ‘Independence’ switchgrass

AbstractSwitchgrass (Panicum virgatum L.), a valuable forage and bioenergy crop, is established more easily than other native perennial warm‐season grasses, but its establishment is still slower than that of annual crops. Vigorous switchgrass establishment is crucial for achieving its full potential yield and for effectively competing with weeds for water and nutrient availability. To satisfy this demand, ‘Independence’ (Reg. no. CV‐295, PI 704577) switchgrass was developed at the University of Illinois at Urbana‐Champaign. Independence was selected for establishment vigor, winter survivorship, and high biomass yield for two cycles from ‘Kanlow’. It is characterized by rapid establishment, robust seedling growth, and the capacity to achieve peak production by the second year. Independence is well adapted to USDA hardiness zones 5b–7b. In field experiments conducted from 2016 to 2017, averaged over seven locations and all years, Independence annually yielded 13 Mg ha−1 of biomass, outperforming ‘Cave‐in‐Rock’ by 31%, ‘Liberty’ by 15%, ‘Shawnee’ by 42%, ‘Summer’ by 81%, and ‘Sunburst’ by 129%. In wet marginal sites in Illinois from 2020 to 2023, Independence exhibited an average biomass yield of 12 Mg ha−1, outperforming Shawnee by 31%, Liberty by 27%, and Kanlow by 19%, indicating its potential use on less productive land for annual crops. Independence was publicly released by the University of Illinois at Urbana‐Champaign in October 2021.

System shift in rice: Processes and pathways of change in rice-based production systems of Southeast Asia

CONTEXTPredicting future production trends and associated land use and management practices requires an understanding of past changes in productivity and of pathways of evolving system configurations. We argue that rice systems' evolution reflects a process of adaptation to changing availabilities of production resources and the adoption of technological innovations and that differs by marginality/favorability of sites. Understanding past change trends and their determinants can help avoiding undesirable future developments and guide policy decisions for a sustained supply of rice. OBJECTIVEWe aimed to assess agronomic system change and practices, to quantify pathways of change and to identify likely drivers of but also possible risks or opportunities associated with observed patterns of agronomic system transformation in six representative lowland rice production environments in Asia. METHODSWe implemented a diachronic analysis (years 2000 vs. 2018) of rice production practices and yield attributes in 1024 households. We documented changes between 2000 and 2018 in lowland rice-based systems in six rice-growing environments in the Philippines, Myanmar and Cambodia, differentiating marginal and favorable sites in irrigated and in rainfed environments. RESULTS AND CONCLUSIONFarmers' household attributes, resource endowment, rice yields, and key constraints differed among sites. We observed relatively low annual yield in marginal (2.2–3.0 t/ ha) than favorable (3.3–8.9 t/ ha) sites depending on countries and seasons. The farmers adopted intensification related agronomic practices has increased significantly between 2000 and 2018, especially in dry season (i.e., improved seeds by 28%, mechanical tillage by 52%, direct seeding by 21%, combined harvester by 62%). The marginality of climatic and edaphic conditions, the systems' evolutionary state in 2000, and differential pressures (policy environment), opportunities (technological change) and household attributes (resource endowment) determined the observed transition pathways across study sites. SIGNIFICANCEThe trends towards maximizing land use intensity (double or multiple cropping), converging in the emergence of high-input and highly mechanized (laborsaving) in irrigated, and diversified rotations in rainfed rice production systems may help to elucidate agricultural research needs and potentially predict the requirements for future sustainable intensification of rice-based systems. Additionally, we argue for a continued need for further mechanization of rice establishment, especially shifting from transplanting to direct seeding during dry and wet seasons, and of the rice harvest, especially during wet season under fully irrigated environments.

Early production of switchgrass (Panicum virgatum L.) and willow (Salix spp.) indicates carbon accumulation potential in Appalachian reclaimed mine and agriculture soil

AbstractThe production of bioproduct feedstocks such as switchgrass (Panicum virgatum L.) and willow (Salix spp.) on degraded lands provides an opportunity to grow dedicated bioenergy crops with the potential to capture and store carbon in the soil while reducing competition with land for food production. However, how the production of these crops alters plant–soil–microbe interactions that govern soil C accumulation in highly degraded soil is underexplored. The objectives of this study were to examine select biological and chemical properties related to stable soil organic matter (SOM) production from the growth of switchgrass and willow on marginal soil over two growing seasons and whether biochar amendment can positively affect these parameters. To address our objectives, paired former surface mined lands and non‐mine impacted marginal agriculture sites were selected across West Virginia, USA, and biochar and unamended control treatments were imposed. Through the first two growing seasons, microbial activity and demand for carbon (C) increased and was accompanied by a shift in extracellular enzyme investment for decomposition‐associated enzymes. Mineral‐associated organic matter C increased over the two growing seasons, and this increase was greater in the mine sites compared to the agriculture sites. Compared to each site's previous land use, C losses were observed under bioproduct systems in the agriculture, but not the mine sites. Biochar amendments did not impact microbial activity but did increase the C:N of SOM. Overall, our results suggest that the early growth of switchgrass and willow can result in C accumulation in marginal and highly degraded lands.

Different patterns of inter-annual variability in mean vessel area and tree-ring widths of beech from provenance trials in Slovenia and Hungary

Key messageStudied beech provenances showed different patterns of inter-annual variability in mean vessel area and ring widths, indicating influence of intraspecific variability and diverse environment on hydraulic conductivity and carbon storage potential.International provenance trials of ecologically and economically important tree species are crucial to deciphering the influence of environmental factors and intraspecific variability on tree growth and performance under climate change to guide assisted gene flow and assisted migration of tree provenances and species. In this context, we compared inter-annual trends in tree-ring widths (carbon sequestration potential) and vessel characteristics (conductivity optimisation) of four beech provenances in two international provenance trials, one in Slovenia (Kamenski hrib, a core beech growing site) and one in Hungary (Bucsuta, a marginal beech site) in 2009–2019. We found different patterns of inter-annual variability in mean vessel area and tree-ring widths among provenances and sites, pointing to diverse genetic background and environmental influence on these two wood-anatomical traits. The average values of the vessel area varied less between provenances at Kamenski hrib than at Bucsuta. Weather conditions differently affected tree-ring width and mean vessel area. Furthermore, the length of the period of response of vessel area to the analysed weather conditions differed in summer and winter periods. The differences in the mean vessel area within the tree ring were more pronounced in the weather-wise extreme years, regardless of the provenance. Consistent with previous studies, we confirmed that site conditions affect the climate sensitivity of trees, which is more pronounced at marginal sites or in extreme years. The findings on how different environmental conditions affect the radial growth of young beech trees of different origin are very important for future forest management.

High temperatures and low soil moisture synergistically reduce switchgrass yields from marginal field sites and inhibit fermentation

Abstract‘Marginal lands’ are low productivity sites abandoned from agriculture for reasons such as low or high soil water content, challenging topography, or nutrient deficiency. To avoid competition with crop production, cellulosic bioenergy crops have been proposed for cultivation on marginal lands, however on these sites they may be more strongly affected by environmental stresses such as low soil water content. In this study we used rainout shelters to induce low soil moisture on marginal lands and determine the effect of soil water stress on switchgrass growth and the subsequent production of bioethanol. Five marginal land sites that span a latitudinal gradient in Michigan and Wisconsin were planted to switchgrass in 2013 and during the 2018–2021 growing seasons were exposed to reduced precipitation under rainout shelters in comparison to ambient precipitation. The effect of reduced precipitation was related to the environmental conditions at each site and biofuel production metrics (switchgrass biomass yields and composition and ethanol production). During the first year (2018), the rainout shelters were designed with 60% rain exclusion, which did not affect biomass yields compared to ambient conditions at any of the field sites, but decreased switchgrass fermentability at the Wisconsin Central–Hancock site. In subsequent years, the shelters were redesigned to fully exclude rainfall, which led to reduced biomass yields and inhibited fermentation for three sites. When switchgrass was grown in soils with large reductions in moisture and increases in temperature, the potential for biofuel production was significantly reduced, exposing some of the challenges associated with producing biofuels from lignocellulosic biomass grown under drought conditions.

Efficient degradation of rhodamine B by MoS2 modified Co-MOF derived nitrogen-doped carbon activated peroxymonosulfate

How to improve the issues of ion agglomeration and metal ion leaching, and how to prepare cobalt-based catalysts with high reactivity and stability, are highly desired yet challenging. In this paper, MoS2 modified Co-MOF derived nitrogen-doped carbon (Co/PCN/MoS2) microspheres rich in active sites were prepared using a simple carbonation-hydrothermal method, with g-C3N4, MoS2 and Co-MOF to overcome the aforementioned limitations. The flower-like nanostructure of MoS2 contributed to exposing more marginal active sites, allowing the high dispersion of Co-MOF within its structure. Meanwhile, Mo4+/Mo6+ and S species coexisted in MoS2, which promoted the valence cycle and electron transfer process, and improved the catalytic activity of the composite. The successful synthesis of Co/PCN/MoS2 was proved by XRD, SEM and FTIR characterizations. The electrochemical performance analysis showed that Co/PCN/MoS2 exhibited higher redox capacity than MoS2, and Co/PCN/MoS2/PMS system achieved the degradation rate of RhB as high as 97.19% within 30 min, which is higher than that of Co-MOF/g-C3N4/PMS (80.67%), Co-MOF/MoS2/PMS (78.08%), Co-MOF/PMS (77.00%), g-C3N4/PMS (53.68%) and MoS2/PMS (28.10%) systems. It had good anti-interference ability against coexisting substances, achieved good degradation performance in a wide pH range (pH 2.0–10.0), and possessed excellent stability and reusability with RhB degradation rate of 91.10% after 5 cycles. The quenching test confirmed that non free radical 1O2 is the main ROS for RhB degradation. This work is expected to provide a new idea and direction for the design and development of metal-doped heterogeneous catalysts with high activity and stability.

Pathways and determinants of changing nutrient management in lowland rice-based systems of Southeast Asia

Production increases in lowland rice-based systems of Southeast Asia will not be possible without the addition of nutrients. Recent productivity gains were largely based on increasing the use efficiency of the applied nutrients through integrated and site-specific approaches. The adoption of such strategies has evolved differentially in the various country. We need to understand such recent trends, their driving forces, and their effectiveness to harness or leverage them for regional food security and sustainable development. To gain this understanding, we analyzed changes in fertility-related agronomic practices in six representative rice-based production systems of Southeast Asia (three favorable and three marginal sites). We implemented a diachronic survey (comparing the years 2000 and 2018) combined with field sampling and measurements in 1024 rice-producing households and, where applicable, in both dry and wet seasons (3638 complete data sets). We observed that soil fertility management followed similar trends across sites. However, the timing and the extent of changes were location specific, and differed primarily by the favorability/marginality of the site, and farmers’ capability to adopt technological innovations. The irrigated rice double cropping benefitted most from recent technology innovations (hybrid seeds, farm machinery), accelerating the adoption of improved fertility management practices to an aggregated level of up to 75% (mean across the six soil fertility-related management practices) at favorable sites. Most prominent were multiple splitting of mineral N and the application of mineral fertilizers other than N (P, K, Zn). At marginal sites, aggregate changes toward intensification were rather low with 35–55%, and farmers tended to intensify the non-rice component in the system by applying mineral fertilizers and organic amendments to dry season upland crops. A balanced use of nutrients will require the targeting of options to specific extrapolation domains (social-ecological target environments) based on site attributes and farmers’ resource endowment.

Identifying biomass yield potential of tetra‐, hexa‐, and octoploid prairie cordgrass populations grown on marginal lands

AbstractAs the demand for renewable energy sources with reduced carbon emissions to the atmosphere increases, bioenergy crops remain an attractive alternative to fossil fuels. Another appeal of bioenergy crops is the potential utilization of marginal lands not suitable for food crops. Prairie cordgrass is a perennial warm‐season polyploid grass species that is considered a bioenergy crop that also exhibits a high tolerance for salinity and flooding. The ploidy level of prairie cordgrass has previously been suggested to correlate with agronomic traits. However, little is known about the agricultural performance of prairie cordgrass on marginal lands and if a correlation of ploidy level and stress tolerance exists. In this experiment, the productivity of tetra‐, hexa‐, and octoploids was investigated when grown on three different marginal sites, including waterlogged, saline, and low‐nutrient gravelly soils. Here, we found that prairie cordgrass populations annually produced dry biomass on a wet marginal site comparable to normal cropland. However, the productivity was remarkedly decreased at both a salt‐affected site and a limestone mine reclamation site. We were unable to conclude that different ploidy levels affected the biomass yield of prairie cordgrass grown under abiotic stress. However, there was a differential response of populations to various types of marginal sites. These results indicate potential genetic resources for developing breeding targets and identifying mechanisms of abiotic stress tolerance. Moreover, we highlight the need to generate diverse ploidy levels of prairie cordgrass in the same genetic backgrounds for future testing.

The Shahrazād of Sablakh Speaks in Many Tongues

Abstract Shlūmū al-kurdī wa-anā wa-l-zaman (Shlūmū al-Kurdī, Myself and Time) (2004) is the final novel of Iraqi-Jewish author Samīr Naqqāsh. Considering the text in light of the cultural politics of memory and articulation, this article posits the novel as a true fabrication of a fictionalized memoir. By thematizing aspects of speech, movement and scriptural ecumenism within an Islamicate cultural memory, the text simultaneously narrates and mourns the WWI-era social collapse of multiconfessional Sablakh in Iranian Kurdistan. The narration employs a modified, self-amplifying tripartite narrative structure and a self-sustaining momentum born of the looping of prophetic and traumatic temporalities; together, such structural moves enable a cascade of witnessing of a marginal(ized) site of loss. The text thus intervenes in officially sanctioned genealogies of loss and overcoming while crafting an affirmative Eastern Jewish self-in-community beyond the linguistic, geographic, and epistemological confines of Mizrahi identity within the State of Israel.

PSVI-5 Using Red Clover Extract to Mitigate Tall Fescue Toxicosis

Abstract Tall fescue toxicosis is caused by ergot alkaloids produced by the fungus Neotyphodium coenophialum that resides within the majority of the tall fescue plants in the Southeastern and lower Midwestern US. Tall fescue (Festuca arundinacea) toxicosis is estimated to cost livestock producers over $1 billion dollars annually through reduced growth and reproductive performance. Improvements in performance by cattle grazing toxic tall fescue can have substantial economic advantages for livestock producers throughout the tall fescue region. Numerous methods to mitigate tall fescue toxicosis have been tried over the past 60+ years, but a practical solution to this problem has not been discovered to date. Forages used to dilute fescue include clovers which will not compete on much of the marginal sites that tall fescue predominates. As mentioned above, clovers have been used to dilute toxic fescue and have shown to be a good mitigation strategy if the clovers persist. Red clover extract (RCE) has shown promise in the mitigation of symptoms related to tall fescue toxicosis, but effective dosages have not yet been determined to date. Dorper ewe and wether lambs (n = 30, 34 ± 0.97 kg initial BW) were weighed and assigned randomly to one of five diets in a 2-period study. Diets consisted of a positive control of non-toxic tall fescue seed with no RCE (CONT), a negative control of toxic tall fescue seed with no RCE (E+0) and toxic tall fescue seed with RCE supplemented at 0.33 (E+33), 0.67 (E+67), and 1 (E+100) percent of the diet. Fescue seed was mixed with liquid molasses to ensure consumption, and seed, DDGS and RCE was offered at approximately 0800 and 1600 h, and bermudagrass hay was offered for ad libitum consumption. Lambs were housed in individual 1 × 1.5 m pens in an enclosed building where temperature was maintained at 27° C (80° F). The animal had an ad libitum access to water. Each period consisted of a 14-day adaptation period followed by 7 d of total fecal and urine collection. Diets were offered for ad libitum consumption during the first 12 days of each period and then held constant during the remaining 9 days. Dry matter (DM) and organic matter (OM) intake was greater (P < 0.05) from CONT than all other treatments and E+33 was greater (P < 0.05) than E+10 and E+67. Digestibility of DM and OM were greater (P < 0.05) from CONT than all other treatments. By contrast, the diets did not influence (P > 0.05) nitrogen balance, urinary nitrogen losses, fecal nitrogen losses and nitrogen retained. Overall, results demonstrated that RCE inclusion into the diet of toxic tall fescue did not significantly change growth and performance parameters in sheep.

Fabricating fragmented intramolecular D-A integrated carbon nitride photocatalyts with elevating activity: Performance and mechanism analysis

Carbon nitride (CN) possesses great potential in photocatalytic solar-energy conversion for environmental pollution removal and hydrogen energy generation. However, pristine CN suffers unsatisfactory photocatalytic activity owing to insufficient visible light response, low activity sites exposure, lazy exciton separation and ready carrier recombination. In this work, fragmented intramolecular D-A integrated CN (FBCN) was contracted via a facile m-aminophenylboronic acid doping followed two-step post-processing. The intramolecular D-A integrated structure can strengthen exciton separation and carrier migration driving forces, while the fragmented nanoflakes structure with rich in-plane edges can shorten the migration distance of charge-to-surface in-plane and vertical direction, as well as expose more marginal active sites. The hydrogen evolution rate of optimized 25-FBCN photocatalyst reaches 2545 μmol h−1 g−1, which is 5.2 times higher than that of pristine CN and 1.3 times over the 25-BCN. The 25-FBCN can degrade 87% sulfamethoxazole, and the kinetic rate constant is 3.9 times higher than that of CN. The radical capture and ESR tests reveal stronger radical signals in 25-FBCN degradation system than that of CN. The MS and online FTIR present photodegradation pathway and intermediate, and in-site record functional groups variation during degradation reaction. The SEM/TEM/AFM/XPS/EPR, N2 adsorption-desorption and water contact analysis confirm the generation of smaller-sized nano fragments with rich in-plane edges. The UV–vis DRS/EIS/PCR/PL/TRPL and band structure verify that more effective charge dissociation/migration behavior of 25-FBCN than pure CN. Finally, DFT theoretical calculations and KPFM test further verify the generation of intramolecular D-A integrated structure and clarify the latent propel mechanism of performances.

Ultra-thin WS2 decorated Co-based Metal‒organic framework derived materials for synergistic electrocatalysis towards pH-Universal hydrogen evolution reaction

Rational designing of a WS2-based hybrid material is extremely important to resolve low-edge sites and poor conductivity of bare WS2, but it is still challenging to construct applicable structures. In this study, an electrocatalyst with ultra-thin WS2 nanosheets homogeneously decorated on Co–N-co-doped carbon hollow nanocages (WS2-3/Co–N–CN-750) is developed, which has favorable hydrogen evolution reaction (HER) activity and stability. The performance of WS2-3/Co–N–CN-750 is significantly improved due to the collective synergy of the specific micro-morphology, interfacial structure, and electronic property. The hybridization of WS2 and Co9S8 can optimize the electronic structure, reduce hydrogen adsorption energy, slash the decomposition barrier of H2O, and accelerate the electron transfer to WS2. Furthermore, the marginal sites of WS2 are significantly increased by optimizing the aggregation growth of WS2. Besides, the precipitation of appropriate Co particles and the Co-based metal-organic framework (Co-MOF) lay a solid foundation for the favorable conductivity of the hybrid material. However, samples after stability tests reveal that cobalt sulfide is corroded and transformed in a locally strong alkali condition. This study highlights the synergies of multicomponent hybridization and provides insights into the stability of congeneric materials.

Small-scale variation in available water capacity of the soil influences height growth of single trees in Southern Germany

Aim of study: Detecting possible small-scale soil effects on height growth of single trees in monospecific stands of three important tree species (Abies alba, Fagus sylvatica, and Picea abies).
 Area of study: 37 mature stands along an ecological gradient in Southern Germany from the cold and wet “optimal niche zone” to warmer and drier niche zones, including gravelly soils with poor water supply.
 Material and methods: Measurement of achieved height and age of 15 to 20 sample trees per stand. Estimation of the available water capacity of the soil (AWC) in close proximity to sample trees based on soil texture following the German soil survey guidelines. Examining height growth depending on niche zone and AWC. 
 Main results: On sites (stand level) with the lowest water regime, height growth increased significantly with AWC of microsites. The estimated effect on height growth over the whole range of AWC values was almost 8 m at those sites. In contrast, the effect was negative on optimal sites. For intermediate and marginal sites, the effect was positive, albeit not significant for marginal sites.
 Research highlights: To our knowledge this is the first study about small-scale effects of AWC on height growth of single trees in temperate European forests. Small-scale soil variability should be considered in future scientific studies and practical evaluation, involving single tree performance at stands with low water regime. This seems particularly important in genetic environmental associations studies and in the process of selecting trees for breeding purposes in such stands.

An 11,000 year record of plant community stability and paludification in a patterned rich fen in northeastern Alberta, Canada

Patterned rich fens have a diverse flora and are maintained by unidirectional inflowing water with high concentrations of base cations, along with high pH and limited nutrients. Rich fens are among the most threatened ecosystems in Europe, but are not uncommon across the western boreal forest zone of Canada. Utilizing 10 radiocarbon dated cores extracted from the wetland, we investigated the Holocene developmental history of a large patterned rich fen in northeastern Alberta (McClelland Wetland). Organic matter accumulation began around 11,457 cal yr BP as primary peat formation on recently deglaciated substrates. Over the 10,000+ years history of McClelland Wetland, the central portions of the wetland have been remarkably resistant to change, with little alteration in dominant species. The resistance to change is set against a background of fluctuations in regional Holocene climate and local varying water balance. The dominant bryophyte species ( Hamatocaulis vernicosus and Scorpidium scorpioides) continued to play a foundational role on site for the duration of the Holocene, dependent on a persistent long-term ground water source. Accumulation rates of organic matter have remained steady once the dominant bryophyte layer was established, but with accumulation rates at paludifying marginal sites lower than those of the central moss-graminoid-dominated areas.

Population decline in a Pleistocene refugium: Stepwise, drought-related dieback of a South Australian eucalypt

Refugia can facilitate the persistence of species under long-term environmental change, but it is not clear if Pleistocene refugia will remain functional as anthropogenic climate change progresses. Dieback in populations restricted to refugia therefore raises concerns about their long-term persistence. Using repeat field surveys, we investigate dieback in an isolated population of Eucalyptus macrorhyncha during two droughts and discuss prospects for its continued persistence in a Pleistocene refugium. We first confirm that the Clare Valley in South Australia has constituted a long-term refugium for the species, with the population being genetically highly distinct from other conspecific populations. However, the population lost >40 % of individuals and biomass through the droughts, with mortality being just below 20 % after the Millennium Drought (2000–2009) and almost 25 % after the Big Dry (2017–2019). The best predictors of mortality differed after each drought. While north-facing aspect of a sampling location was significant positive predictor after both droughts, biomass density and slope were significant negative predictors only after the Millennium Drought, and distance to the north-west corner of the population, which intercepts hot, dry winds, was a significant positive predictor after the Big Dry only. This suggests that more marginal sites with low biomass and sites located on flat plateaus were more vulnerable initially, but that heat-stress was an important driver of dieback during the Big Dry. Therefore, the causative drivers of dieback may change during population decline. Regeneration occurred predominantly on southern and eastern aspects, which would receive the least solar radiation. While this refugial population is experiencing severe decline, some gullies with lower solar radiation appear to support relatively healthy, regenerating stands of red stringybark, providing hope for persistence in small pockets. Monitoring and managing these pockets during future droughts will be essential to ensure the persistence of this isolated and genetically unique population.