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Within-field variation of actual and maximum winter wheat yield in relation to crop management
Get PDFContext: The potential magnitude of agronomic yield gain through management is rarely explored at the field scale. Increasing yield through greater use of inputs without considering local potential yield may pose environmental and economic risks. Study objectives: i) examine yield gain through increased management intensity, including irrigation, and how it varies within and between fields, ii) evaluate the environmental and economic risks of uniform N-rates within fields. Methods: Field experiments were performed at three sites, with varying yield potential, in each of 12 fields with winter wheat (Triticum aestivum L.) in Sweden over three years. Irrigated and rainfed maximum yield under non-limiting cropping inputs (Yim and Ym), actual yield under conventional management (Ya), and yield gains (Yim-Ym and Ym-Ya) were determined. Results: More frequent pest control was most effective to increase yields, followed by higher fertilizer rates. However, within-field yield variation, relative to the lowest yield recorded in the field, was, on average, similar for Ya and Ym but reduced by irrigation (Yim). Thus, water limitation was the main reason for within-field yield variations, possibly related to soil texture. Conclusions: Actual and maximum yields vary between and within fields. This variation cannot be entirely compensated for by intensified management. Therefore uniform yield levels within fields should not be strived for, instead site-specific optimal levels should be the goal. Implications: The within-field variation in yield needs to be considered as N rates based on site-specific yield levels within fields were found to be more profitable than uniform N rates
Rise and fall of a spruce bark beetle outbreak-Importance of colonisation density and reproductive success
Get PDFTree-killing bark beetles are an important disturbance factor in conifer forests. We studied if bark beetle performance in colonised trees may influence outbreak progression. Trees colonised by the Eurasian spruce bark beetle Ips typographus were sampled during an entire outbreak triggered by a storm-felling in southern Sweden. The study was conducted at nine storm gaps where no sanitation cuttings were done. Colonisation density (maternal gallery density) and reproductive success (daughters per mother) of I. typographus, and densities competitors and enemies, were recorded from bark samples collected in the autumn from colonised storm-felled and standing trees during seven years. Yearly colonisation densities were much lower in storm-felled (68-103 galleries per m2) than in standing trees (218-717 galleries per m2). For standing trees the lowest colonisation densities occurred in the first two years of the outbreak and colonisation density was positively related to tree diameter. Beetle reproductive success was higher in storm-felled (9.4-9.6 daughters per mother) than standing trees (0.4-5.7 daughters per mother). In standing trees the highest values occurred in the first two years of the outbreak. Reproductive success was significantly related to colonisation density (negatively), tree diameter (positively), parasitoid density (negatively at high densities) and attack year (negatively). Colonisation density had the largest effect. Our results demonstrate the importance of managing spruce forest in a way that increases tree vitality and minimises the risk for storm-fellings. Timely sanitation cuttings of colonised storm felled and low-vitality standing trees may reduce the risk for outbreak initiations
Exploring the occurrence of DNA-fragmentation in Arctic charr sperm (Salvelinus alpinus) and its impact on embryo viability
Get PDFSperm from Arctic charr sires can contain high levels of DNA fragmentation. Nevertheless, the frequency of this phenomenon and its impact on embryo viability are not fully known. The current study aimed to further elucidate the extent of DNA fragmentation in Arctic charr sperm through a comprehensive sampling of Swedish hatcheries. Furthermore, associations between sperm DNA fragmentation and subsequent embryo viability were investigated. Arctic charr males (n = 166) were sampled from five major Swedish hatcheries, and DNA fragmentation, together with sperm concentration and viability, were recorded. Fragmentation levels were classified as: intact, moderate, severe, and stellar fragmentation. The median DNA fragmentation level (severe to stellar fragmentation) was 32 % (5-50 %; n = 93). Moreover, the median sperm concentration was 3.6 x 109 cells/ml (range 0.3-11.5 x 109) and cell viability was 90 % (range 68-96 %). Significant differences in sperm concentration, cell viability, and DNA fragmentation were found among the five hatcheries (Kruskal-Wallis,
Soil organic carbon in dry miombo landscapes decreases with higher grazing intensity, but trees can counteract the effect
Get PDFSoil organic carbon is one of the key determinants of soil quality and productivity, contributing to food production and mitigation ofclimate change. Vegetation, particularly trees, is essential in maintaining and enhancing soil organic carbon. However, there is alack of knowledge on the ability of trees to enhance soil organic carbon in the presence of high-intensity livestock grazing. Here,we conducted a study in Morogoro Rural District, Tanzania, where we established a 10 × 10 km study site covering part of theKitulangalo forest reserve and surrounding areas. We identified four main land uses and land cover types: forest reserve, openaccess forest, cropland under fallow, and cropland under cultivation. We assessed soil organic carbon stocks, livestock grazingintensity, and tree basal area in 149 plots. We also tested the effect of total grazing exclusion in two 12-years-old fenced plotslocated within the forest reserve. Topsoil organic carbon stocks were higher in land use classes with higher tree cover; At lowgrazing intensity, the forest reserve had the highest mean topsoil organic carbon (51 ± 8 tones ha−1) and that this decreased withdecreasing tree cover across land uses, with croplands under cultivation having the lowest value (32 ± 12 tones ha−1). We foundthat soil organic carbon declined with increased grazing intensity, but this decrease was higher in croplands, with a 64% decreaseto 12 ± 8 tones ha−1 when comparing the lowest and highest grazing intensities. In contrast, the decrease in forested lands was18% to 42 ± 17 tones ha−1. We conclude that increasing livestock grazing intensity has a negative impact on soil organic carbon,particularly in land uses with a low tree cover, and that more trees in the landscape have the potential to counteract the adverseeffects of livestock grazing
Biostimulants-induced improvements in pea-barley intercropping systems: A study of biomass and yield optimization under Ukrainian climatic conditions
Get PDFThe challenge of enhancing crop yields sustainably is critical in modern agriculture. This study investigated the effectiveness of various biostimulants (extracts derived from insect frass, compost, humic material, seaweeds, and fish hydrolysate) on the yield of barley and peas in sole and intercropped systems. Results demonstrated that pea-barley intercrop delivered higher grain yields compared to pea or barley sole crops, with a maximum yield of 7.08 t/ha achieved using compost tea. Barley grain yields in pea-barley intercrop ranged from 4.72 to 5.57 t/ha with biostimulant applications compared to 4.39 t/ha without biostimulant (control) treatment. While pea sole cropping did not show significant yield improvements with biostimulants, intercropped pea yields increased significantly, with humus extract and compost tea enhancing yields by 61.9 % and 45.4 %, respectively. The application of biostimulants also increased the number and weight of seeds per spike in barley and the number of seeds per plant, seed weight per plant, and thousand seed weight in peas. Although intercropping resulted in fewer spikes compared to sole crops, barley produced more grain per spike, with the highest increase observed with seaweed extract. The stimulatory role of biostimulants is associated with their anti-stress action and rhizosphere stimulation for increased N-fixing activity explaining certain increases in productivity, and consequently in the yield of crops, especially in pea-barley intercrop where there is intense competition between species during the generative period of development. Furthermore, the overall land equivalent ratio (LER) for the pea-barley intercropping system was consistently above 1.0, indicating a consistent yield advantage over monoculture throughout the growing season. These findings indicate that biostimulants and intercropping synergistically enhance crop yields and biomass, promoting sustainable agricultural practices by optimizing resource use and minimizing chemical inputs
Trålundersökning av fisk i Västerhavet
Get PDFIBTS trålexpedition i Västerhavet genomförs två gånger årligen, i kvartal 1 och 3, och täcker Skagerrak, Kattegatt och delar av östra Nordsjön.Dagtid används bottentrålen Grande Ouverture Verticale (GOV). Under expeditionen genomfördes totalt 48 godkända tråldrag med GOV-trålen, 6 i Nordsjön, 23 i Skagerrak och 19 i Kattegatt. Den totala fångsten uppgick till knappt 25,8 ton (ca 57 % utgjordes av sillfiskar) och inkluderade 72 fiskarter. Den biologiska provtagningen, som också innefattar insamling av otoliter för åldersbestämning, gjordes på de kommersiellt betydelsefulla arterna. Totalt togs 5308 otoliter från 10 olika arter. Preliminära abundansindex för 1-gruppen hos målarterna redovisas i rapporten.Larvtrålningen nattetid resulterade i ovanligt många (60) godkända tråldrag pga gynnsamt väder och det fångades bl.a. 186 sillarver, 110 sardinlarver och 29 glasålar
An in vitro evaluation of partial energy replacement in a total mixed ration with volatile fatty acids derived from agro-industrial residues
Get PDFThe scientific interest in volatile fatty acids (VFAs) as an energy source and chemical precursor in ruminant diets has been longstanding, as it has significant implications for animal physiology and well-being. The present study explores the substitution of volatile fatty acids (VFAs) derived from agro-food residues via acidogenic fermentation as an alternative energy source in ruminant feed. Utilizing the gas production method, rumen digestibility assays were conducted, wherein the recovered VFA effluent from the acidogenic fermentation of apple pomace and potato protein liquor was substituted for 10%, 20%, and 30% of the total mixed ration (TMR) energy. Various parameters such as gas, VFA yield and composition, VFA peak intervals, changes in pH, and ammonium nitrogen content were investigated. Based on the results obtained, provision of 20% and 30% of the energy with VFAs did not increase methane production or did not cause significant pH alternations. Nevertheless, such supplementation resulted in increased production and accumulation of VFAs in the rumen media. The bioconversion of agro-food side streams into VFAs opens a new path in sustainable nutrient recovery and feed production from low value agro-industrial residues
Monensin Suppresses Multiple Features of House Dust Mite-Induced Experimental Asthma in Mice
Get PDFDespite intense efforts to develop efficient therapeutic regimes for asthma, there is a large demand for novel treatment strategies in this disease. Here we evaluated the impact of monensin, a drug with potent anti-mast cell effects, in a mouse model of asthma. Allergic airway inflammation was induced by sensitization of mice with house dust mite (HDM) antigen, and effects of monensin on airway hyperreactivity and inflammatory parameters were studied. Following intraperitoneal administration, monensin did not suppress airway hyperreactivity but was shown to have anti-inflammatory properties, as manifested by reduced eosinophil- and lymphocyte infiltration into the airway lumen, and by suppressed inflammation of the lung tissue. After intranasal instillation, monensin exhibited similar anti-inflammatory effects as seen after intraperitoneal administration. Moreover, intranasally administered monensin was demonstrated to suppress goblet cell hyperplasia, and to cause a reduction in the expression of genes coding for key inflammatory markers. Further, monensin blocked mast cell degranulation in the airways of allergen-sensitized mice. Together, this study reveals that monensin has the capacity to suppress key pathological events associated with allergic airway inflammation
Boreal tree species classification using airborne laser scanning data annotated with harvester production reports, and convolutional neural networks
Get PDFThis study explores the potential of spatially explicit Harvester Production Reports (HPRs) for automatic annotation of Aerial Laser Scanning (ALS) data at tree-level, enabling accurate tree species classification using Convolutional Neural Networks (CNNs). By integrating HPRs into the modelling process, this approach provides a practical solution for addressing challenges in remote sensing data annotation for forestry applications. The ALS data were acquired in managed Norway spruce-dominated forests in southern Sweden using a dual-wavelength system composed by two monochromatic sensors. Thus, three datasets were produced: the 905 nm miniVUX dataset (similar to 100 points/m(2)), the 1550 nm VUX dataset (similar to 875 points/m(2)), and the dual-wavelength dataset (similar to 975 points/m(2)), the last being a junction of the two first datasets. The automatic annotation was performed by matching tree records in the HPR and ALS data based on spatial proximity and height similarity, with a total of 45,516 HPR-recorded tree positions being linked to ALS-derived segments and assigned species labels based on HPR records. Then, the individual tree-level ALS point clouds were converted into 2D images from multiple viewing angles, with varying image dimensions and pixel sizes to accommodate trees of different sizes. These images served as input for CNN-based classification, enabling species identification across ALS datasets with varying spectral and spatial resolutions. The CNN models were trained and evaluated to classify trees into Norway spruce, Scots pine, Deciduous, and a "Noise" class for segmentation errors. The classification accuracy varied according to the dataset used, with the dual-wavelength dataset achieving the highest macro-F1 score (0.896), followed by the VUX dataset (0.894) and miniVUX dataset (0.835). These findings highlight spatially explicit HPRs as efficient, high-quality reference data for CNN-based tree species classification with minimal annotation effort
Cellular damage triggers mechano-chemical control of cell wall dynamics and patterned cell divisions in plant healing
Get PDFReactivation of cell division is crucial for the regeneration of damaged tissues, which is a fundamental process across all multicellular organisms. However, the mechanisms underlying the activation of cell division in plants during regeneration remain poorly understood. Here, we show that single-cell endodermal ablation generates a transient change in the local mechanical pressure on neighboring pericycle cells to activate patterned cell division that is crucial for tissue regeneration in Arabidopsis roots. Moreover, we provide strong evidence that this process relies on the phytohormone ethylene. Thus, our results highlight a previously unrecognized role of mechano-chemical control in patterned cell division during regeneration in plants