| 1. |
- Bergstrand, Kjell, et al.
(författare)
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Dynamics of nitrogen availability in pot grown crops with organic fertilization
- 2019
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Ingår i: Biological Agriculture & Horticulture. - : Informa UK Limited. - 0144-8765 .- 2165-0616. ; 35:3, s. 143-150
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Tidskriftsartikel (refereegranskat)abstract
- Pot grown herbs are often cultivated as certified organic products, and there is an increasing demand for organically certified ornamental plants. Supplying the required nutrients using organic fertilizers is a challenge with respect to matching the mineralization and thus the availability of dissolved nutrients in the growing medium with plant demand. In experiments, sweet basil and Pelargonium × hortorum were cultivated using two different organic fertilizer strategies and controlled-release mineral nutrients as control treatment. The two organic strategies were, i) blood meal + Baralith® Enslow (a plant-based organic fertilizer), and ii) poultry manure. The availability of dissolved nitrogen was monitored during the crop cycle by under-pressure lysimeter sampling. Plant development parameters were measured along with chlorophyll fluorescence and chlorophyll concentration of leaves. For both organic treatments, nitrate-N availability was low at the beginning of the experiment, whereas ammonium-N was high. During the experiment, ammonium availability decreased at the same time as nitrate availability increased after a few weeks and then declined again by the end of the experiment. The blood meal + Enslow treatment caused poor germination and slow growth in basil. Plant height and fresh weight was also affected by this treatment for basil but not for Pelargonium. Chlorophyll concentration was affected by treatment, with also visually detectable paler leaves in the treatment with poultry manure. There were no differences in chlorophyll fluorescence (Fv/Fm) between treatments, indicating that plants were not stressed in any of the treatments.
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| 2. |
- Bergstrand, Karl-Johan, et al.
(författare)
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Nulägesanalys trädgård
- 2018
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Rapport (populärvet., debatt m.m.)abstract
- Rapporten Nulägesanalys - trädgård har genomförts inom ramen för projektgruppen Insatsstyrka trädgård. Syftet med inventeringen har varit att ge svar på vem som jobbar med trädgårdsvetenskap, vilka forskargrupper och med vilka forskningsämnen, samt identifiera framtida arbetsfält inom ämnet trädgårdsvetenskap och därmed ge uppslag för framtida utveckling av forskningsfält, utbildning och samverkan. I detta ingår att kartlägga trädgårdsvetenskaplig forskning, utbildning och samverkan vid SLU. Nulägesanalysen förväntas därmed ge en grund för fortsatt strategiskt arbete med att utveckla ämnet trädgårdsvetenskap (Horticultural Science) utifrån inventerade resurser och förutsättningar.
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| 3. |
- Ahlman, Linnéa, 1987, et al.
(författare)
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Stress Detection Using Proximal Sensing of Chlorophyll Fluorescence on the Canopy Level
- 2021
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Ingår i: AgriEngineering. - : MDPI AG. - 2624-7402. ; 3:3, s. 648-668
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Tidskriftsartikel (refereegranskat)abstract
- Chlorophyll fluorescence is interesting for phenotyping applications as it is rich in biological information and can be measured remotely and non-destructively. There are several techniques for measuring and analysing this signal. However, the standard methods use rather extreme conditions, e.g., saturating light and dark adaption, which are difficult to accommodate in the field or in a greenhouse and, hence, limit their use for high-throughput phenotyping. In this article, we use a different approach, extracting plant health information from the dynamics of the chlorophyll fluorescence induced by a weak light excitation and no dark adaption, to classify plants as healthy or unhealthy. To evaluate the method, we scanned over a number of species (lettuce, lemon balm, tomato, basil, and strawberries) exposed to either abiotic stress (drought and salt) or biotic stress factors (root infection using Pythium ultimum and leaf infection using Powdery mildew Podosphaera aphanis ). Our conclusions are that, for abiotic stress, the proposed method was very successful, while, for powdery mildew, a method with spatial resolution would be desirable due to the nature of the infection, i.e., point-wise spread. Pythium infection on the roots is not visually detectable in the same way as powdery mildew; however, it affects the whole plant, making the method an interesting option for Pythium detection. However, further research is necessary to determine the limit of infection needed to detect the stress with the proposed method.
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| 4. |
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| 5. |
- Alsanius, Beatrix, et al.
(författare)
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Degradation of Pesticides in Nutrient Solution from Closed Hydroponic Systems
- 2014
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Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1034, s. 33-39
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Konferensbidrag (refereegranskat)abstract
- To protect aquatic systems in the Baltic Sea area, zero eutrophication has been proclaimed as one of the Swedish environmental goals. Closed hydroponic systems are generally used today to meet standards on reduced release of excess nutrient-rich drainage water from horticulture. In recent years, concerns have been expressed about emissions of plant protection products (PPP) from indoor cultivation systems to aquatic environments in the vicinity of commercial greenhouses. Some of the active ingredient in pesticides applied to the crop can end up in the nutrient solution (i) after canopy application, through plant run-off and infiltration through the growing medium or into collecting gutters, or (ii) after direct administration to the nutrient solution. This study monitored the concentrations of three PPP (fenhexamid, FEX; pyrimethanil, PYR; imidacloprid, IMI) on six occasions over 21 days in colonised nutrient solution obtained from a closed cropping system for greenhouse tomatoes and incubated at 20°C in darkness. The experiment with FEX (added at 0.01 times the recommended spray concentration) was conducted as a full-scale experiment with six replicates and examined the dynamics of microbiota associated with the nutrient solu¬tion. Monitoring of PYR and IMI (added at 0.01 and 1 times the recommended spray concentration, respectively) comprised chemical analysis of the compound in single samples on six sampling occasions. The results indicate that all three PPP persisted for 21 days in the microbe-colonised nutrient solution under the experimental conditions used.
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| 6. |
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| 7. |
- Alsanius, Beatrix, et al.
(författare)
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Integrated greenhouse production in new light: prospects on improved LED-assisted biocontrol of foliar diseases
- 2020
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Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; , s. 293-296
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Horticultural greenhouse production in circumpolar regions (>60°N latitude) is dependent of artificial assimilation lighting, which is a common tool to improve plant performance and consequently profitability of ornamental crops and to secure production of greenhouse vegetables and berries all year round. The anticipated light technology shift in the greenhouse industry not only affects crop growth and development but also quality of the produce. It also influences the interactions with the associated microbiota, i.e., community structure and function as well as establishment, dispersal, survival and propagation of microbial pathogens and biocontrol agents. We present a novel ecological theory and principle based approach for integrated production of greenhouse crops, using improved LED-assisted biocontrol of foliar diseases.
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| 8. |
- Alsanius, Beatrix, et al.
(författare)
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Light and Microbial Lifestyle: The Impact of Light Quality on Plant-Microbe Interactions in Horticultural Production Systems-A Review
- 2019
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Ingår i: Horticulturae. - : MDPI AG. - 2311-7524. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Horticultural greenhouse production in circumpolar regions (>60 degrees N latitude), but also at lower latitudes, is dependent on artificial assimilation lighting to improve plant performance and the profitability of ornamental crops, and to secure production of greenhouse vegetables and berries all year round. In order to reduce energy consumption and energy costs, alternative technologies for lighting have been introduced, including light-emitting diodes (LED). This technology is also well-established within urban farming, especially plant factories. Different light technologies influence biotic and abiotic conditions in the plant environment. This review focuses on the impact of light quality on plant-microbe interactions, especially non-phototrophic organisms. Bacterial and fungal pathogens, biocontrol agents, and the phyllobiome are considered. Relevant molecular mechanisms regulating light-quality-related processes in bacteria are described and knowledge gaps are discussed with reference to ecological theories.
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| 9. |
- Alsanius, Beatrix, et al.
(författare)
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Nedbrytningsstudie av bekämpningsmedel i näringslösning
- 2012
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Ingår i: LTJ-fakultetens faktablad.
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Annan publikation (populärvet., debatt m.m.)abstract
- I vattendrag i växthustäta områden har bekämpningsmedelsrester kunnat spåras. En trolig väg är att bekämpningsmedelsrester tar sig ur växthuset via dräneringslösningen. För slutna odlingssystem skulle det kunna innebära att bekämpningsmedel som rinner ner i odlingssubstratet, öppna uppsamlingskanaler av dräneringsvatten eller direkt in i näringslösningen inte – som förutsatt – bryts ner, utan förekommer i näringslösningen efter karenstidens slut. Bekämpningsmedel i en recirkulerande näringslösning kan endast försvinna genom kemisk eller biologisk nedbrytning. Vi testade i en inledande studie • om bekämpningsmedelsrester finns efter karenstidens slut och • hur snabbt de eventuellt kan brytas ner. Teldor WG 50 används mot gråmögel i tomatodling. Vi använde Teldor WG50 som modellsubstans (aktiv substans: fenhexamid) i en hundradelskoncentration av en vanlig sprutlösning. Undersökningen pågick under 21 dagar, dvs sju gånger längre än preparatets karenstid. Prover togs vid 6 tillfällen, nämligen 0, 1, 2, 4, 8 eller 21 dagar efter tillsats av substansen. Utöver detta följde vi halten av organiska ämnen, ledningstal och pH samt förekomsten av bakterier och svampar (levande celltal) i medier utan och med Teldor samt dynamiken av mikrobiella samhällen under inkubationen. Vi undersökte också om det fanns bakterier och svampar som kan växa till med Teldor som enda energikälla. Vi konstaterade att • halten fenhexamid inte förändrades under observationsperioden; • halten löst organiskt kol inte förändrades under observationsperioden; • ledningstalet och pH ökade något under observationsperioden; • levande celltal (CFU/ml) av bakterier och svampar varierade inte nämnvärt under observationsperioden; • levande celltal av fluorescerande pseudomonader ökade något under observationsperioden; • levande celltal av svampar påverkades signifikant då de odlades i medium med fenhexamid; • organismer från dräneringslösningen överlevde väl under de näringsfattiga betingelserna på vattenagar med tillsats av Teldor; • sammansättningen av mikrobiella samhällen i dräneringslösningen förändrades över tid i närvaro av Teldor. Vi drar slutsatsen att fenhexamid inte bryts ner i näringslösning under den tre dagar långa karenstiden, att rester av Teldor kan kvarstå under en lång tid i näringslösning och att mikroorganismer i dräneringslösningen inte bidrog till nedbrytningen av det tillsatta bekämpningsmedlet.
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| 10. |
- Alsanius, Beatrix, et al.
(författare)
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New challenges for organic greenhouse horticulture in Sweden
- 2020
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Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; , s. 1079-1084
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Swedish consumers buy increasing amounts of organic food. Also, the Swedish Government aspires to increase food sovereignty and volume of organic food stuff in public meals from 36 (2017) to 60% in 2030. There is a substantial mismatch between demand and the production of organic vegetables. Today, 4.9% of the total greenhouse area in Sweden is used for organic production. The majority of organic production of greenhouse vegetables in Sweden is performed in containers and confined beds. The approval of the revised European regulation for organic farming in 2018 reinforces production in natural soil, leads to dramatic changes for organic greenhouse horticulture in Sweden. Confined beds need to be phased out. Cultivation methods that conserve or increase organic matter in the soil should be used. Thus, soil bound systems using crop rotations and soil fertility maintaining activities need to be implemented. This corroborates with increased burden of soil borne diseases and lower yields. Such systems, well established in southern Europe, cannot be translated to northern European conditions, due to constraints in climate and day length, as well as constraints due to greenhouse construction (permanent construction). This presentation displays the challenges and consequences to meet the changed legislation.
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