| 1. |
- Anderbrant, Olle, et al.
(författare)
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Pheromone of the elm bark beetle Scolytus laevis (Coleoptera Scolytidae) : stereoisomers of 4-methyl-3-heptanol reduce interspecific competition
- 2010
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Ingår i: Chemoecology. - : Springer Science and Business Media LLC. - 0937-7409 .- 1423-0445. ; 20:3, s. 179-187
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Tidskriftsartikel (refereegranskat)abstract
- Stereoisomers of 4-methyl-3-heptanol (MH) are pheromone components of several Scolytus bark beetles. The elm bark beetle Scolytus laevis (Coleoptera: Scolytidae) has in previous studies been caught in traps baited with commercial MH containing all four stereoisomers, but the lure has been considered a weak attractant. In this study, we addressed the question whether stereospecific responses by S. laevis to stereoisomers of MH might contribute to its niche separation from other sympatric Scolytus species. Using GC-MS, we analyzed extracts of hindguts and abdomens from male and female S. laevis and the sympatric S. triarmatus. We also tested all four MH-stereoisomers individually and in combinations in the field to determine their role for S. laevis. All four stereoisomers were synthesized via a boronic ester method with 1,2-dicyclohexylethanediol as chiral director. In addition, the (3S,4R)-stereoisomer of MH was prepared through enantioselective, lipase-mediated transesterification of a mixture of the four stereoisomers of MH. Females of both species contained small amounts of syn-MH, and males contained trace amounts of anti-MH. The anti stereoisomer (3R,4S)-MH was attractive to male and female S. laevis, whereas the syn stereoisomer (3S,4S)-MH acted as an inhibitor or deterrent and reduced the catch when added to the attractive isomer. The syn isomer is the main aggregation pheromone component of the larger and sympatric S. scolytus and possibly also of S. triarmatus. The avoidance response of S. laevis to the (3S,4S)-stereoisomer may reduce interspecific competition for host trees.
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| 2. |
- Adediran, Gbotemi A., et al.
(författare)
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Phosphorus in 2D : Spatially resolved P speciation in two Swedish forest soils as influenced by apatite weathering and podzolization
- 2020
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Ingår i: Geoderma. - : Elsevier BV. - 0016-7061 .- 1872-6259. ; 376
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Tidskriftsartikel (refereegranskat)abstract
- The cycling and long-term supply of phosphorus (P) in soils are of global environmental and agricultural concern. To advance the knowledge, a detailed understanding of both the vertical and lateral variation of P chemical speciation and retention mechanism(s) is required, a knowledge that is limited in postglacial forest soils. We combined the use of synchrotron X-ray fluorescence microscopy with multi-elemental co-localisation analysis and P K-edge XANES spectroscopy to reveal critical chemical and structural soil properties. We established a two-dimensional (2D) imagery of P retention and speciation at a microscale spatial resolution in two forest soil profiles formed in glaciofluvial and wave-washed sand. The abundance and speciation of P in the upper 40 cm was found to be influenced by soil weathering and podzolization, leading to spatial variability in P speciation on the microscale (< 200 pm) with P existing predominantly as organic P and as PO4 adsorbed to allophane and ferrihydrite, according to XANES spectroscopy. These species were mostly retained at sharp edges and in pore spaces within Al and Si-bearing particles. Despite the relatively young age ( < 15,000 years) of the soils, our results show primary mineral apatite to have weathered from the surface horizons. In the C horizon however, a large fraction of the P was in the form of apatite, which appeared as widely dispersed ( > 600 pm) hot spots of inclusions in aluminosilicates or as discrete micro-sized apatite grains. The subsoil apatite represents a pool of P that trees can potentially acquire and thus add to the biogeochemically active P pool in temperate forest soils.
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| 3. |
- Aliabad, Fahime Arabi, et al.
(författare)
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Use of Landsat 8 and UAV Images to Assess Changes in Temperature and Evapotranspiration by Economic Trees following Foliar Spraying with Light-Reflecting Compounds
- 2022
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Ingår i: Remote Sensing. - : MDPI AG. - 2072-4292. ; 14:23
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Tidskriftsartikel (refereegranskat)abstract
- Pistachio is an important economic crop in arid and semi-arid regions of Iran. A major problem leading to a reduction in crop quality and reduced marketability is extreme air temperature in summer, which causes sunburn of pistachio leaves and fruit. A solution proposed to deal with the negative effects of high temperatures and increase water consumption efficiency in pistachio orchards is use of light-reflecting compounds. This study investigated the effect of foliar application of gypsum, sulfur, and NAX-95 (calcium-based suspension coating) to trees in a pistachio orchard (150 ha) in central Iran. The effect of these foliar products is assessed at plot scale, using control plots sprayed with calcium sulfate, based on temperature and evapotranspiration changes analyzed through remote sensing. Landsat 8 sensor images and RGB images collected by UAVs (spatial resolution of 30 m and 20 cm, respectively), on the same dates, before and after foliar spray application, were merged using the PCA method and bilinear interpolation re-sampling. Land surface temperature (LST) was then estimated using the split-window algorithm, and daily evapotranspiration using the surface energy balance algorithm for land (SEBAL) algorithm. A land use map was prepared and used to isolate pistachio trees in the field and assess weed cover, whose effect was not accounted. The results showed that temperature remained constant in the control plot between the spraying dates, indicating no environmental changes. In the main plots, gypsum had the greatest effect in reducing the temperature of pistachio trees. The plots with foliar spraying with gypsum displayed a mean tree temperature (47–48 °C) decrease of 3.3 °C in comparison with the control plots (>49 °C), leading to an average decline in evapotranspiration of 0.18 mm/day. NAX-95 and sulfur reduced tree temperature by on average 1.3 °C and 0.6 °C, respectively. Thus, gypsum is the most suitable foliar-spraying compound to lower the temperature of pistachio trees, reduce the water requirement, and increase crop productivity.
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| 4. |
- Azeem, Muhammad, et al.
(författare)
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Chemical composition and antifeedant activity of some aromatic plants against pine weevil (Hylobius abietis)
- 2020
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Ingår i: Annals of Applied Biology. - : Blackwell Publishing Ltd. - 0003-4746 .- 1744-7348.
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Tidskriftsartikel (refereegranskat)abstract
- The pine weevil Hylobius abietis is an important pest causing severe damage to conifer seedlings in reforestation areas in Europe and Asia. Plants that have no evolutionary history with the pine weevil are of special interest in the search for compounds with a strong antifeedant activity. Thus, the essential oils of nine aromatic plants, viz Amomum subulatum, Cinnamomum tamala, Curcuma longa, Laurus nobilis, Ocimum basilicum, Origanum majorana, Origanum vulgare, Syzygium aromaticum and Trachyspermum ammi were extracted by hydrodistillation. The essential oil constituents were identified by gas chromatography–mass spectrometry, and antifeedant properties towards the pine weevil were assessed using choice feeding bioassay. The essential oils of C. longa, O. majorana, S. aromaticum and T. ammi showed an excellent antifeedant activity towards the pine weevil for 24 hr, whereas the essential oil of other plants showed the activity for 6 hr. There was a positive correlation between the amount of benzenoid compounds and the antifeedant activity of the essential oils. This study suggests that pine weevil non-host plant compounds have potential to be used for the protection of seedlings against pine weevil feeding. However, further study will be needed to explore the antifeedant activity of individual components and oils in the laboratory as well as in the field.
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| 5. |
- Berglund, Torkel, et al.
(författare)
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Protection of spruce seedlings against pine weevil attacks by treatment of seeds or seedlings with nicotinamide, nicotinic acid and jasmonic acid
- 2016
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Ingår i: Forestry (London). - : Oxford University Press. - 0015-752X .- 1464-3626. ; 89:2, s. 127-135
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Tidskriftsartikel (refereegranskat)abstract
- Sustainable methods are required to protect newly planted tree seedlings from insect herbivore attack. To this end, here Norway spruce (Picea abies (L.) Karst.) seeds were treated with 2.5 mM nicotinamide (NIC), 2.5 mM nicotinic acid (NIA), 3 mM jasmonic acid (JA) or 0.2 mM 5-azacytidine (5-Aza), and 6-month-old seedlings grown from these seeds were planted at a reforestation area in central Sweden. Attack by pine weevils (Hylobius abietis) was reduced by 50 per cent by NIC treatment, 62.5 per cent by JA treatment and 25 per cent by 5-Aza treatment, when compared with seedlings grown from untreated seeds. Watering 18-month-old spruce seedlings with 2 mM NIC or 2 mM NIA did reduce attack during the first season in the field by 40 and 53 per cent, respectively, compared with untreated plants. Girdling was also reduced by the different treatments. Analysis of conifer seedlings treated with 5-Aza points at a possible involvement of epigenetic mechanisms in this defensive capacity. This is supported by a reduced level of DNA methylation in the needles of young spruce seedlings grown in a greenhouse from NIC-treated seeds. Seed treatment for seedling defense potentiation is simple, inexpensive and also a new approach for forestry with many potential applications.
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| 6. |
- Boulet, Anne Karine, et al.
(författare)
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Agro-ecological services delivered by legume cover crops grown in succession with grain corn crops in the Mediterranean region
- 2021
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Ingår i: OPEN AGRICULTURE. - : Walter de Gruyter GmbH. - 2391-9531. ; 6:1, s. 609-626
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Tidskriftsartikel (refereegranskat)abstract
- Grain corn is the main cereal produced in Portugal. It is grown in intensive monoculture cropping systems that may have negative effects on soil quality, affecting long-term fertility and productivity, and, therefore, the sustainability of the production. A promising management practice to mitigate soil degradation is to grow winter cover crops used as green manure. This study examined the effectiveness of six legume cover crops (LCCs) species in providing agro-ecological services for grain corn systems in the Mediterranean region, specifically in terms of nutrient leaching, nutrient recycling, weed control, and soil fertility. The study was performed in Central Portugal during 2 years, and it assessed legumes/weeds dry biomass yield, their nutrients content, and soil organic matter evolution. Results show that, in general, LCC are well adapted to Mediterranean conditions, yielding large amounts of biomass (up to 8 ton/ha for some clover species). In terms of nutrient leaching mitigation, the overall N-P-K nutrient uptake was 176-20-172 kg/ha. Green manure services enabled a reduction of 35% of N, 50% of P, and 100% of mineral fertilizers for a grain corn production of 12 ton/ha. Weed control by LCC was effective only in the second year of the study and for three clover species (crimson, balansa, and arrowleaf) due to their early establishment and/or high biomass production competing with weeds. Soil fertility was not improved in the short term, LCC incorporation into the soil to a slight depletion of the soil organic matter content.
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| 7. |
- Gustafsson, Jon Petter, 1964-, et al.
(författare)
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Aluminium and base cation chemistry in dynamic acidification models - need for a reappraisal?
- 2018
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Ingår i: SOIL. - : COPERNICUS GESELLSCHAFT MBH. - 2199-3971 .- 2199-398X. ; 4:4, s. 237-250
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Tidskriftsartikel (refereegranskat)abstract
- Long-term simulations of the water composition in acid forest soils require that accurate descriptions of aluminium and base cation chemistry are used. Both weathering rates and soil nutrient availability depend on the concentrations of Al3+, of H+, and of base cations (Ca2+, Mg2+, Na+, and K+). Assessments of the acidification status and base cation availability will depend on the model being used. Here we review in what ways different dynamic soil chemistry models describe the processes governing aluminium and base cation concentrations in the soil water. Furthermore, scenario simulations with the HD-MINTEQ model are used to illustrate the difference between model approaches. The results show that all investigated models provide the same type of response to changes in input water chemistry. Still, for base cations we show that the differences in the magnitude of the response may be considerable depending on whether a cation-exchange equation (Gaines-Thomas, Gapon) or an organic complexation model is used. The former approach, which is used in many currently used models (e.g. MAGIC, ForSAFE), causes stronger pH buffering over a relatively narrow pH range, as compared to state-of-the-art models relying on more advanced descriptions in which organic complexation is important (CHUM, HD-MIN PLQ). As for aluminium, a "fixed" gibbsite constant, as used in MAGIC, SMART/VSD, and ForSAFE, leads to slightly more pH buffering than in the more advanced models that consider both organic complexation and Al(OH)(3) (s) precipitation, but in this case the effect is small. We conclude that the descriptions of acid-base chemistry and base cation binding in models such as MAGIC, SMART/VSD, and ForSAFE are only likely to work satisfactorily in a narrow pH range. If the pH varies greatly over time, the use of modern organic complexation models is preferred over cation-exchange equations.
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| 8. |
- Kimming, Marie, et al.
(författare)
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Replacing fossil energy for organic milk production : potential biomass sources and greenhouse gas emission reductions
- 2015
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 106, s. 400-407
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Tidskriftsartikel (refereegranskat)abstract
- There is a growing awareness of the climate impact of agricultural production, not least from cattle farms. Major sources of GHG emissions from milk production are enteric fermentation followed by fossil fuel use and manure/soil management systems. This study analyzes the potential to eliminate fossil fuel use from milk production farms in Sweden, by using residual farm resources of biomass to obtain self-sufficiency in fuel, heat and electricity. The change from a fossil-based energy system to a renewable system based on A) Biogas based on manure and straw and B) Biogas based on manure + RME were analyzed with consequential life cycle assessment (CLCA) methodology. Focus was energy use and GHG emissions and the functional unit was 1 kg of energy-corrected milk (ECM). The results show that organic milk producers can become self-sufficient in energy and reduce total GHG emissions from milk production by 46% in the Biogas system, or 32% in the Biogas + RME system compared to the Fossil system.
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| 9. |
- McGivney, Eric, et al.
(författare)
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Assessing the impact of acid rain and forest harvest intensity with the HD-MINTEQ model - soil chemistry of three Swedish conifer sites from 1880 to 2080
- 2019
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Ingår i: SOIL. - : COPERNICUS GESELLSCHAFT MBH. - 2199-3971 .- 2199-398X. ; 5:1, s. 63-77
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Tidskriftsartikel (refereegranskat)abstract
- Forest soils are susceptible to anthropogenic acidification. In the past, acid rain was a major contributor to soil acidification, but, now that atmospheric levels of S have dramatically declined, concern has shifted towards biomass-induced acidification, i.e. decreasing soil solution pH due to tree growth and harvesting events that permanently remove base cations (BCs) from forest stands. We use a novel dynamic model, HD-MINTEQ (Husby Dynamic MINTEQ), to investigate possible long-term impacts of two theoretical future harvesting scenarios in the year 2020, a conventional harvest (CH, which removes stems only), and a whole-tree harvest (WTH, which removes 100 % of the above-ground biomass except for stumps) on soil chemistry and weathering rates at three different Swedish forest sites (Aneboda, Gardsjon, and Kindla). Furthermore, acidification following the harvesting events is compared to the historical acidification that took place during the 20th century due to acid rain. Our results show that historical acidification due to acid rain had a larger impact on pore water chemistry and mineral weathering than tree growth and harvesting, at least if nitrification remained at a low level. However, compared to a no-harvest baseline, WTH and CH significantly impacted soil chemistry. Directly after a harvesting event (CH or WTH), the soil solution pH sharply increased for 5 to 10 years before slowly declining over the remainder of the simulation (until year 2080). WTH acidified soils slightly more than CH, but in certain soil horizons there was practically no difference by the year 2080. Even though the pH in the WTH and CH scenario decreased with time as compared to the no-harvest scenario (NH), they did not drop to the levels observed around the peak of historic acidification (1980-1990), indicating that the pH decrease due to tree growth and harvesting would be less impactful than that of historic atmospheric acidification. Weathering rates differed across locations and horizons in response to historic acidification. In general, the predicted changes in weathering rates were very small, which can be explained by the net effect of decreased pH and increased Al3+, which affected the weathering rate in opposite ways Similarly, weathering rates after the harvesting scenarios in 2020 remained largely unchanged according to the model.
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| 10. |
- Röös, Elin, et al.
(författare)
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Risks and opportunities of increasing yields in organic farming. A review
- 2018
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Ingår i: Agronomy for Sustainable Development. - : Springer-Verlag France. - 1774-0746 .- 1773-0155. ; 38:2
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Tidskriftsartikel (refereegranskat)abstract
- Current organic agriculture performs well in several sustainability domains, like animal welfare, farm profitability and low pesticide use, but yields are commonly lower than in conventional farming. There is now a re-vitalized interest in increasing yields in organic agriculture to provide more organic food for a growing, more affluent population and reduce negative impacts per unit produced. However, past yield increases have been accompanied by several negative side-effects. Here, we review risks and opportunities related to a broad range of sustainability domains associated with increasing yields in organic agriculture in the Northern European context. We identify increased N input, weed, disease and pest control, improved livestock feeding, breeding for higher yields and reduced losses as the main measures for yield increases. We review the implications of their implementation for biodiversity, greenhouse gas emissions, nutrient losses, soil fertility, animal health and welfare, human nutrition and health and farm profitability. Our findings from this first-of-its-kind integrated analysis reveal which strategies for increasing yields are unlikely to produce negative side-effects and therefore should be a high priority, and which strategies need to be implemented with great attention to trade-offs. For example, increased N inputs in cropping carry many risks and few opportunities, whereas there are many risk-free opportunities for improved pest control through the management of ecosystem services. For most yield increasing strategies, both risks and opportunities arise, and the actual effect depends on management including active mitigation of side-effects. Our review shows that, to be a driving force for increased food system sustainability, organic agriculture may need to reconsider certain fundamental principles. Novel plant nutrient sources, including increased nutrient recycling in society, and in some cases mineral nitrogen fertilisers from renewable sources, and truly alternative animal production systems may need to be developed and accepted.
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