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Soil Carbon Dynamics During Stand Rotation in Boreal Forests
Get PDFThe utilisation of forest resources is frequently criticised for its adverse environmental impacts. In particular, the widespread use of rotation forestry practices, including clear-cutting, is viewed as a threat to ecosystems. Clear-cutting has short-term impacts that turn the forest into a net carbon (C) source, but such modifications to the ecosystem also have long-term effects. Any analyses of alternative management approaches should include at least one full rotation, which requires model extrapolations. In this study, we used data from a well-documented series of long-term forest monitoring sites in Finland (ICP Forests Level II), focusing on two recent clear-cut sites-one dominated by Scots pine and the other by Norway spruce. These data were utilised to constrain a soil C model and to extrapolate two future scenarios: rotation forestry and set-aside (unmanaged). We simulated these scenarios over a period exceeding one full rotation and compared the outcomes. Although the stand thinning events did not heavily affect the C balance of the studied sites, clear-cutting did. Each clear-cut event caused a negative soil organic carbon (SOC) balance for many decades. It took between 37 and 69 years (for Norway spruce and Scots pine, respectively) to reach a break-even point in which soil C losses compensated for C uptake. Emissions from coarse harvest residuals represented the greatest C source after clear-cutting, followed by fine roots and then foliage. When comparing such a scenario with a set-aside scenario, the soil C budget of the managed stand after clear-cut was negative until the first thinning or even until the following clear-cut, while the set-aside was always a C sink in soil. Thus, scenario analyses of forest C sequestration that disregard long-term soil C dynamics following management interventions may lead to biased conclusions. As a management regime, rotation forestry was relatively ineffective when evaluated considering C sequestration as an important ecosystem service
Effects of converting cropland to grassland on greenhouse gas emissions from peat and organic-rich soils in temperate and boreal climates: a systematic review
Get PDFBackgroundTo align with climate goals, greenhouse gas (GHG) emissions from agriculture must be reduced significantly. Cultivated peatlands are an important source of such emissions. One proposed measure is to convert arable fields on peatlands to grassland, as the Intergovernmental Panel on Climate Change (IPCC) default emission factors (EF) for organic soils are lower from grasslands. Yet, these EFs are based on limited data with high variability and comparisons are difficult due to differences in climate, soil properties, and crop management. This systematic review synthesizes available evidence on the effects of converting cropland to grassland on GHG emissions from peat and organic-rich soils in temperate and boreal climates using data from comparable fields.MethodsLiterature was searched using five bibliographic databases, four archives or search engines for grey literature, and Google Scholar. Eligibility screening was performed in two steps on (1) title/abstract, with consistency among reviewers assessed by double-screening 896 articles, and (2) full text screened by two reviewers. Eligible articles were critically appraised independently by at least two reviewers. Disagreements were reconciled through discussions. Data and key metadata are presented in narrative synthesis tables, including risk of bias assessments. Meta-analyses comparing grasslands with croplands were performed using raw mean difference as the effect size.Review findingsA total of 10,352 unique articles were retrieved through the literature searches, and 18 articles including 29 studies were considered relevant to answer the review question. After critical appraisal, it was concluded that two articles reported the same data, so a total of 28 studies, comprising 34 comparisons were included in the systematic review. Most of the included studies were conducted in the Nordic countries and Germany, one in Belarus and one in Canada. A meta-analysis was conducted on 24 studies pairing cropland and grassland sites. No significant differences in carbon dioxide (CO2) or methane (CH4) emissions were found. Emissions of nitrous oxide (N2O) from grasslands were found to be 7.55 kg ha-1 y-1 lower than from cropland, however the sensitivity analysis showed that the difference was not robust, making it uncertain whether conversion from cropland to grassland has a significant effect on N2O emissions from organic soils. The difference was also smaller when root crops were excluded from the comparator group. Further, net ecosystem exchange (NEE) of CO2 and net ecosystem carbon balance (NECB) were higher in grasslands compared to croplands in cases where the grasslands were fertilized.ConclusionsThis systematic review underlines the ambiguity of GHG emissions from peatlands and their relationship to land use. Our understanding of the factors influencing emissions from these soils remains incomplete, and the specific impact of land use on emissions is still unclear. CO2 emissions represent a major part of the climate impact of cultivated peat soils, so the data analyzed allow to draw the conclusion that a conversion from arable to grassland would not lead to large benefits in terms of GHG emissions, especially if root crops are not part of the arable crop rotation, or the grassland is fertilized
Effekt av olika gräsarter och sorter på mjölkavkastning
Get PDFPå Lantmännens försöksgård Viken utfodrades 48 mjölkkor fyra olika foderstater där grovfodret bestod antingen av hundäxing (Dactylis glomerata) av sorten Swante, ängssvingel (Festuca pratensis) av sorten Tored eller timotej (Phleum pratense L.) av sorterna Ragnar eller Switch. Inga skillnader i mjölkavkastning, eller mjölkens sammansättning kunde konstateras, men det var brister i foderregistreringen som gör att inga säkra slutsatser kan dras av försöket.Försöket bidrar ändå med kunskap genom att ett stort antal analyser utförts som kan vara en referens till andra studier. Särskilt är analyserna av ligninkomponenter och hydroxykanelsyror ovanliga och ger värdefull kunskap.Ett intressant resultat är att sammansättningen av de lättlösliga kolhydraterna skiljer sig mellan timotej och de andra gräsen. Förhållandet mellan glukos och fruktos är ungefär 50/50 medan det var betydligt högre andel fruktos i hundäxing och ängssvingel
Trees First Inhibit Then Promote Litter Decomposition in the Subarctic
Get PDFTrees affect organic matter decomposition through allocation of recently fixed carbon belowground, but the magnitude and direction of this effect may depend on substrate type and decomposition stage. Here, we followed mass loss, chemical composition and fungal colonisation of leaf and root litters incubated in mountain birch forests over 4 years, in plots where belowground carbon allocation was severed by tree girdling or in control plots. Initially, girdling stimulated leaf and root litter mass loss by 12% and 22%, respectively, suggesting competitive release of saprotrophic decomposition when tree-mediated competition by ectomycorrhizal fungi was eliminated (Gadgil effect). After 4 years, girdling instead hampered mass loss of root litter by 30%, suggesting late-stage priming of decomposition in the presence of trees, in parallel with increased growth of shrubs and associated fungi following tree elimination. Hence, different mechanisms driving early- and late-stage litter decomposition should be considered in climate-feedback evaluations of plant-soil interactions
Priced out of belonging? Insufficient concessions on membership fees across international societies in ecology and evolution
Get PDFLearned societies, as professional bodies for scientists, are an integral part of the scientific system. However, their membership fees have the potential to be prohibitive to the most vulnerable members of the scientific community. To shed light on how membership fees are structured, we conducted a survey of 182 international learned societies relevant to researchers in ecology and evolution. We found that 83% of these societies offered fee concessions to students, but only 26% to postdoctoral researchers. An average regular membership fee—US27.4 (42.7% of the regular fee) and postdoctoral fee—US$42.7 (52.9%). Other types of individual concessions, such as for emeritus, family or unemployed, were rare (2–20%). Of the surveyed societies, 43% had discounts for members from developing countries (Global South). Such discounts were more common among societies located in high-income countries. Societies with a publicly visible commitment to equity, diversity and inclusion were more likely to offer different types of concessions. Currently, fees may prevent researchers from vulnerable and underprivileged groups from accessing multiple professional benefits offered by learned societies in ecology and evolution. This includes postdoctoral researchers, who should receive more support. We recommend tangible actions towards making learned societies more affordable and accessible
Can ultrasonication improve coagulation properties of indigenous and exotic cow milk for dairy product processing?
Get PDFThis study investigates the effects of ultrasonication on milk coagulation properties, focusing on milk from indigenous Thamankaduwa White (TW) and exotic Holstein Friesian (HF) cattle. Milk samples were subjected to ultrasound treatment (20 kHz with a 2 cm probe depth and 60 % amplitude) at three energy densities (504, 612, and 720 J mL- 1). Acid-induced gels were formed using a lactic acid starter culture, while rennet-induced gels were produced through enzymatic coagulation. The results demonstrate that ultrasonication significantly enhances the water-holding capacity (WHC) in both gel types, particularly in HF milk treated at 720 J mL- 1. Ultrasonication also altered gel hardness, cohesiveness, and microstructure, with TW milk showing more pronounced changes. These include larger and more abundant void spaces in rennet gels and a coarser protein network in acid-induced gels. Ultrasonication offers a practical and efficient method to improve dairy product quality by enhancing WHC, hardness, and cohesiveness while reducing syneresis in milk gels. This technology also promotes the utilization of milk from underutilized indigenous cattle breeds, such as TW, in the dairy industry, contributing to sustainability and addressing industry challenges
Characterization of per- and polyfluoroalkyl substances (PFAS) in willow and poplar and the impact of soil amendments on accumulation rates
Get PDFPhytoremediation technologies have the potential to be cost-effective solutions for managing per- and polyfluoroalkyl substances (PFAS). In this greenhouse study, we assessed the uptake of PFAS using two plant species commonly used for phytoremediation, Salix miyabeana (willow) and Populus trichocarpa (poplar). We also assessed the impact of a commercially available growth phytohormone (naphthalene acetic acid (NAA)) and a microbial amendment on plant growth and PFAS uptake. Overall, uptake was observed, depending on perfluorocarbon chain length and functional group. After 90 days, the uptake of individual PFAS in plants grown in PFAS contaminated soil ranged from 0.02 % to 35 % dry weight (dw) for willow and 0.4-29 % for poplar. Within plants, short chain PFAS (i.e., C4-7 perfluoroalkyl carboxylates (PFCA) and C-4 perfluoroalkyl sulfonates (PFSA)) primarily accumulated in aboveground biomass, whereas longer chained homologues (C8-14 PFCA, C6-8 PFSA) primarily accumulated in the roots. For hormone and microbial amendments, there were no statistically significant trends for both willow and poplar (p > 0.05). Interestingly, the microbial community composition did not shift based on PFAS exposure but did shift based on plant-species. The PFAS mass balance for willow and poplar after 90 days approached 100 % (p > 0.05) for all PFAS except PFBA, PFPeA, PFOS, and FOSA. These results suggest that while willow and poplar have the potential to extract short chain PFAS from soil, phytoremediation may be more effective at stabilizing PFAS within a given area (i.e., providing hydraulic control) than extracting
Genome-wide association study of rice (Oryza sativa L.) inflorescence architecture
Get PDFRice yield strongly depends on panicle size and architecture but the genetics underlying these traits and their coordination with environmental cues through various signaling pathways have remained elusive. A genomewide association study (GWAS) was performed to pinpoint the underlying genetic determinants for rice panicle architecture by analyzing 20 panicle-related traits using a data set consisting of 44,100 SNPs. We defined QTL windows around significant SNPs by the rate of LD decay for each chromosome and used these windows to identify putative candidate genes associated with the trait. Using a publicly available RNA-seq data set we performed analyses to identify the differentially expressed genes between stem and panicle with putative functions in panicle architecture. In total, 52 significant SNPs were identified, corresponding to 41 unique QTLs across the 12 rice chromosomes, with the most signals appearing on chromosome 1 (nine associated SNPs), and seven significant SNPs for each of chromosomes 8 and 12. Some novel genes such as Ankyrin, Duf, Kinesin and Brassinosteroid insensitive were found to be associated with panicle size. A haplotype analysis showed that genetic variation in haplotypes qMIL2 and qNSBBH21 were related to two traits, MIL, the greatest distance between two nodes on the rachis, and NSBBH, the number of primary branches in the bottom half of a panicle, respectively. Analysis of epistatic interactions revealed a marker affecting clustered traits. Several QTLs were identified on different chromosomes for the first time which may explain the phenotypic diversity of rice panicle architecture we observe in our collection of accessions. The identified candidate genes and haplotypes could be used in marker-assisted selection to improve rice yield through gene pyramiding
Large heterogeneity in biosecurity legislation in the intensive pig production across Europe
Get PDFImplementing biosecurity measures in the pig production is crucial to optimize animal health and reduce antimicrobial usage. A legal framework may help to ensure all stakeholders understand the need of biosecurity measures and to implement them correctly. Limited knowledge is available about how implementation of biosecurity measures is regulated in European countries. Therefore, the aim of this study was to identify which biosecurity measures were mandatory by national legislation and/or by pig sector organizations of European countries for the intensive pig production under normal circumstances (i.e. no (threat of) disease outbreaks). A questionnaire including 51 biosecurity measures, 32 on external and 19 on internal, was developed and sent to national country representatives. Twenty-four European countries, of which 18 belonging to the European Union, indicated which biosecurity measures were mandatory by law. Four countries, France, Spain, Italy and Romania had a single national pig-specific biosecurity legislation, while in the other countries multiple legislations had to be consulted to complete the questionnaire. In general, there was a high heterogeneity in the number of measures that were mandatory by law per country. Most biosecurity measures addressed in the national legislation focused on external biosecurity and were measures that can be easily audited when conducting a farm visit such as the presence of a hygiene lock, fencing around the farm and the existence of documentation. A significant (p < 0.001) positive correlation was observed between the presence of external and internal biosecurity measures in the legislation. Yet, no significant association was observed between the number of biosecurity measures present in the national legislation and the size of the pig production. Fourteen countries indicated which biosecurity measures were required by pig sector organizations for intensive pig farms. The median number of biosecurity measures mandatory by pig sector organizations but not by law was 13 with a minimum of one measure in Germany and a maximum of 24 in Croatia. Different countries apply different strategies to increase the level of biosecurity. Further research is needed to investigate the impact of the different strategies on the implementation of biosecurity on intensive pig farms in the countries
Genome-wide association scan and candidate gene analysis for seed coat color in sesame (Sesamum indicum L.)
No full textIntroduction: Seed coat color in sesame is a crucial trait for breeding programs as it is closely associated with important characteristics such as oil content, protein levels, and disease resistance, which directly influence seed quality and market value. Methods: This study investigates the genetic basis of seed coat color in 200 Sudanese sesame genotypes grown for two consecutive years through comprehensive phenotyping, genomic diversity analysis, genome-wide association studies (GWAS), and candidate gene discovery. Results and discussion: Phenotypic analysis across two growing seasons revealed high heritability and significant correlations among color parameters (L*, a*, and b*), indicating strong genetic control over seed coat color. The genomic analysis identified distinct clusters among sesame accessions, with rapid linkage disequilibrium decay suggesting a high level of recombination. GWAS identified significant SNPs associated with seed coat color traits, revealing key genomic regions on chromosomes 3, 6, 9, 12, and 13. Candidate gene analysis highlighted several genes, including DOF zinc finger proteins and WRKY transcription factors, which may play essential roles in pigment biosynthesis pathways. These findings provide valuable insights for breeding programs to enhance desirable seed coat color traits in sesame