| 1. |
- Alsanius, Beatrix, et al.
(författare)
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Förundersökning rörande minskat näringsläckage från odlingar med frilandsgrönsaker i Skåne
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Kväve (N) och fosfor (P) är två väsentliga faktorer bakom övergödningsproblematiken. Merparten av de svenska områdena med högt utsläpp av dessa ämnen ligger i södra Östersjön. Områdena kring den skånska kusten har klassats som särskilt känsliga områden. Samtidigt finns det mycket goda förutsättningar i Skåne för odling av kulturer med intensiva produktionsinsatser såsom frilandsgrönsaker. Odling av dessa kulturer förutsätter god tillgänglighet av näringsämnen, särskilt N, samt av vatten. Situationen i dessa kulturer är särskilt känslig i och med att många frilandsgrönsaker skördas i utvecklingsstadier med full tillväxt och då näringsupptaget är som störst. Det finns ett antal redskap för minskning av näringsläckage. Beräkning av växtnäringsbehovet och anpassning av gödslingen är två av dem. För att ytterligare komma tillrätta med problemet finns odlingsåtgärder såsom kvävemur, kalkfilter, reglerad dränering, uppsamling av vatten i dammar samt anläggning av våtmarker. Föreliggande rapport bygger på fallstudier i fem IP-odlingar i Skåne. Vi har utgått ifrån fält i fem pilotföretag med intensiva grönsaksväxtföljder i Skåne. De valda pilotföretagen ligger i vattendistrikten Södra Östersjön och Västerhavet. Pilotytorna varierade i storlek mellan 1 och 25 ha. Vi har analyserat förutsättningar för begränsning av näringsläckaget på pilotytorna ur ett biologiskt-teknologiskt och ekonomiskt perspektiv. I odlarintervjuer sållades möjliga åtgärder fram för begränsning av näringsläckaget på de givna platserna. De av odlarna prioriterade åtgärderna bedömdes sedan också ur ekonomiskt perspektiv. Åtgärder på fältnivå som befanns relevanta att utreda vidare var kalkfilter, kvävemur, våtmark, reglerad dränering, biologisk alvluckring/mullhaltsförbättring samt restaurering av vattendrag med hästskovåtmark samt dammar med fosforavskiljning, rötning av stallgödsel, full Controlled Traffic Farming (CTF) samt bygga en bevattningsdamm. Åtgärder på kulturnivå var bättre behovsanpassning av N och P dels genom förändrade proportioner i NPK-mikro-gödselmedel och dels genom en lärandeprocess med experiment och uppföljning. För de tre företag som inte redan tillämpade radmyllning vid sådd/plantering, till de kulturer där det var möjligt, var detta en relevant åtgärd. Andra åtgärder var bortförsel av skörderester för rötning och In season-CTF, djupluckring efter sättning/plantering, djupluckring vid bäddläggning samt bevattningsramp med slang. Ett försök att skatta effekten av åtgärderna samt beräkna kostnaden per sparat kg näringsämne gjordes på respektive företag. För kvävereduktion fanns viss möjlighet tack vare ungefärliga utlakningsberäkningar gjorda med STANK. Växtnäringsläckaget varierar mycket från fält till fält, från årstid till årstid och från kultur till kultur. Åtgärder i enskilda företag borde bygga på mätningar och kunskap och förutsätter en individuell prövning. De vinster man gör är dels inbesparade gödselmedel, dels miljövinster i form av minskade utsläpp. Dessa besparingar ska sättas i relation till de ökade kostnader som uppkommer
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| 2. |
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| 3. |
- Asp, Håkan, et al.
(författare)
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Anaerobic digestate as peat substitute and fertiliser in pot production of basil
- 2022
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Ingår i: Biological Agriculture & Horticulture. - : Informa UK Limited. - 0144-8765 .- 2165-0616. ; 38, s. 247-257
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Tidskriftsartikel (refereegranskat)abstract
- The common use of peat as a growing medium for plant production is questioned due to the negative effects on the environment and climate. Therefore, it is of great importance to find substitutes for peat with similar positive properties that have made peat one of the most important substrates in the horticultural sector. Production of biogas from organic residues is a valuable process, producing both energy and a residue, anaerobic digestate (AD), with a high content of plant nutrients. In this study, peat was partly substituted with AD of plant material origin up to 80% in a growing substrate for basil (Ocimum basilicum). Germination, yield and plant nutrient content were measured as well as chemical and physical properties of the growing media. The results showed that with 50% substitution of peat the growth in the AD/peat mix gave the same yield as for the fertilised peat on its own. No toxic or deficiency symptoms could be seen in the 50% mix. The important physical properties of the substrate were similar in peat and AD/peat mixes. However, the water-holding capacity was slightly decreased when part of the peat was substituted.
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| 4. |
- Asp, Håkan, et al.
(författare)
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Biogödsel som näringskälla vid hydroponisk odling - nitrifiering och pH
- 2020
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Ingår i: LTV-fakultetens faktablad.
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Möjlighet att odla grönsaker i system som kan vara horisontella, vertikala eller i flera lager och bedrivas i källare och på tak har lett till ett ökande intresse för hydroponisk odling. I denna typ av odling tillförs växten näring genom en näringslösning som cirkulerar i systemet. I dagsläget är mycket av den hydroponiska odlingen baserad på mineralgödselmedel. Att ha möjlighet att i stället använda en recirkulerad näringskälla innebär en fördel ur miljöperspektiv. I detta faktablad beskrivs hur en recirkulerad näringskälla, biogödsel, ska hanteras för att fungera som näringslösning i hydroponisk odling.
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| 5. |
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| 6. |
- Asp, Håkan, et al.
(författare)
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Circularity in practice: reusing restaurant waste for in-house vegetable production
- 2021
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Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; , s. 281-286
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Konferensbidrag (refereegranskat)abstract
- Production of biogas is a common way to handle organic waste products and it provides not only energy but also an anaerobic digestate (AD) rich in plant nutrients. In order to create a close loop between food consumption and vegetable production this project was undertaken to see if food waste from a restaurant, could be used to produce a liquid fertilizer for lettuce production to the same restaurant. Growth experiments in a hydroponic set up were made with nitrified AD. The AD was tested as a hydroponic fertilizer at two dilution levels. In one trial the solution was also amended with mineral nutrients and all the trials were compared to a mineral nutrient control. Results indicate that it is possible to use the digestate as a fertilizer for lettuce, and that amendment with certain mineral nutrients enhances the growth. Plant concentrations of Na and Cl indicates that there might be a problem with toxicity but it was not clarified by these experiments.
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| 7. |
- Asp, Håkan, et al.
(författare)
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Development and Acclimatisation of Horticultural Plants Subjected to Narrow-Band Lighting
- 2014
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Ingår i: European Journal of Horticultural Science. - 1611-4426 .- 1611-4434. ; 79, s. 45-51
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Tidskriftsartikel (refereegranskat)abstract
- Light-emitting diodes (LED) allow narrow-band light to be easily obtained and can be used for narrow-band lighting in plant cultivation, with possible effects on plant growth and development. This study examined use of narrow-band lighting of different wavelengths in the cultivation of ornamental pot plant (Pelargonium and Petunia), tomato (Solanum lycopersicum) transplants and sunflower (Helianthus annuus), either as sole light source in growth chambers, or as end-of-day (EOD) treatment in a greenhouse environment. Biometric measurements on plant growth and measurements of photosynthesis and stomatal conductance showed that when Helianthus was grown exclusively in blue light, stem elongation was greater than when it was grown exclusively in yellow, red, green or white light. Similar results were obtained when blue light was supplied in EOD treatments for Petunia and Pelargonium and for tomato. However, stem elongation was also high when red light was given as EOD treatment to tomato, whereas green light gave the least elongated plants in these conditions. Biomass production was generally not affected by the different EOD treatments. For Helianthus plants grown solely in monochromatic light, plant biomass production was highest in red light. For Pelargonium, photosynthetic rate was highest in blue light. It was conduded that plant response to different wavelengths is species-dependent and that EOD treatment with narrow-band lighting might be useful for plant growth regulation.
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| 8. |
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| 9. |
- Asp, Håkan
(författare)
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Modifiering av biogödsel för ökad användning i krukodling och för minskad torvanvändning
- 2023
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Ingår i: LTV-fakultetens faktablad.
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Biogödsel från biogastillverkning innehåller mycket växtnäring och bör i så stor utsträckning som möjligt återföras till växtodlingen. En fast fraktion av biogödslet bör kunna användas som ett näringsrikt substitut till torv. Denna studie visar att biogödslet kan modifieras genom nitrifikation så att ammoniumhalterna och pH sjunker, vilket bör förenkla inblandningen av det i substrat för hortikulturell produktion.
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| 10. |
- Asp, Håkan, et al.
(författare)
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Nutrient utilization and growth of tomato crops fertilized with solid anaerobic digestate
- 2024
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Ingår i: Scientia Horticulturae. - 0304-4238 .- 1879-1018. ; 329
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Tidskriftsartikel (refereegranskat)abstract
- Anaerobic digestate is a valuable resource for horticultural production, as it contains nutrients and fibers that can be used in plant growing medium. However, compared with hydroponic production based on mineral fertilizers, obtaining accurate nutrient supply at each stage of the growth cycle may be challenging. In an experiment using container-grown tomato crops, we evaluated different fertilization regimes with solid anaerobic digestate (SAD). Four different treatments were compared, two involving different proportions (19 % and 37 % by volume) of SADs in the peat-based growing medium, one treatment where growing medium with 37 % SAD was inoculated with active nitrifying bacteria, and one treatment where 15 % (v/v) of the peat in growing medium with 37 % SAD was replaced with sawdust to control nitrogen (N) availability during cultivation. A mineral-fertilized treatment (N-P-K 5–1-5) with approximately similar N amount as in the treatment with 37 % SAD was used as reference. Nutrient availability, nutrient uptake efficiency, crop performance (plant growth, biomass accumulation), and plant stress (chlorophyll fluorescence) were monitored during cultivation. The concentration of ammonium was initially high (190–416 mg/L substrate) in the growing media fertilized with anaerobic digestate, while the concentration of nitrate was low. Readily available ammonium concentration decreased rapidly during cultivation, to around 50 % after 10 days and to almost 100 % by the end of the cultivation. Available nitrate concentration was initially low (0–8 mg/L in the different treatments) and decreased to zero within a week, but increased slightly from day 40 of cultivation. Nutrient use efficiency was generally higher (15–50 % for different nutrients) in the treatment with 19 % digestate. Inclusion of sawdust in the growing medium decreased nutrient use efficiency by 30–50 %. Compared with the mineral-fertilizer reference, biomass production was lower in all treatments fertilized with digestate, with 37 % and 19 % SAD resulting in 62 % and 47 % of total biomass obtained in the reference, and similar reductions in yield of harvestable fruits. Chlorophyll fluorescence measurements indicated elevated plant stress in the treatments fertilized with SAD. Addition of sawdust or nitrifying bacteria did not help to control nitrogen availability during cultivation. Therefore, anaerobic digestate fertilizers need further optimization before they can be a competitive alternative to mineral fertilizers.
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| 11. |
- Asp, Håkan, et al.
(författare)
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Potential of urban horticulture to secure food provisions in urban and peri-urban environments
- 2014
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Ingår i: Urban and peri-urban agriculture for food security in low-income countries. - 9789157692290 ; :2014:4, s. 33-35
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The production of vegetables and fruits within urban and peri-urban boundaries provides food for million of Africans in urban areas as well as livelihoods for thousands of urban growers. Thus, the socio-economic impact of urban horticulture is substantial. There is also a positivie effect on the environment through conservation of natural resources in city areas. However, there exists a need for technical development and official recognition of this type production to enhance sustainability. Furthermore, microbiological, chemical and physical food hazards need to be acknowledged.
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| 12. |
- Asp, Håkan, et al.
(författare)
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Reflection-in-Action: a Trigger for Acquisition of Higher Horticultural Education Knowledge
- 2009
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Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 832, s. 43-47
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Konferensbidrag (refereegranskat)abstract
- This paper addresses experiences from two examples where practical case studies were used as course starter in order to increase the operational knowledge but also as a tool for increased learning outcomes for theoretical knowledge. The first case presented was performed by freshmen enrolled into a two-year-long horticultural management program and involved greenhouse pot plant production. Each student working group was responsible for one production factor e. g., light, water or nutrients, on one out of four crops (chrysanthemum, poinsettia, basil and tomatoes). Within given frames the details of the study were formed by the students. During the course the trials were discussed in terms of production physiology, statistics, and presentation of results. The second case study discussed was performed by students at an advanced level of the M.Sc. program in Horticulture (5 years). The assignment was to build, and run, an automatic closed hydroponic growing system. The case study was given during the first week of the course with minimal instructions. The set-up was then used in the course for experiments on nutrient analysis, pH regulation, and plant biometrics. Results showed that both case studies had a positive effect on the learning outcome for both theoretical as well as operational knowledge. The cultivation system resulting from the case became a rich source for discussions within the student group and with the supervisors on various subjects during the course. The supervisors found a way, through the case studies, to meet students with different backgrounds on their individual knowledge level. It was also encouraging for the teachers to observe how the personal initiative from the students grew when working with the case studies. Details about the case studies and our experiences as a pedagogical tool are presented and discussed.
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| 13. |
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| 14. |
- Asp, Håkan, et al.
(författare)
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Styr tillväxten med ljuset
- 2019
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Ingår i: LTV-fakultetens faktablad.
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Annan publikation (populärvet., debatt m.m.)abstract
- Ljuset påverkar växterna i stor utsträckning. Både mängden ljus, dagens längd (fotoperioden) samt ljusets kvalité (spektrala sammansättning) påverkar växternas utveckling på olika sätt. Traditionellt har en växthusodlare haft möjlighet att påverka ljusintensiteten (genom skuggning eller tillskotts-belysning) samt fotoperioden (genom dagförlängning eller mörkläggning). Numera är det också möjligt att påverka ljusets spektrala sammansättning genom att anända belysningssystem baserade på LED-teknik. Dessutom har det bli vit allt vanligare med fast installerade mörk-läggningsgardiner för dagslängdsreglering. Detta gör att de tekniska förutsättningarna har förbättrats så att tillväxtreglering med hjälp av ljuset idag är realistiskt som komplement eller alternativ till andra former av tillväxtreglering såsom kemisk retardering eller negativ DIF/Drop.
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| 15. |
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| 16. |
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| 17. |
- 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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| 18. |
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| 19. |
- Bergstrand, Karl-Johan, et al.
(författare)
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Dynamics of nutrient availability in tomato production with organic fertilisers
- 2020
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Ingår i: Biological Agriculture & Horticulture. - : Informa UK Limited. - 0144-8765 .- 2165-0616. ; 36, s. 200-212
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Tidskriftsartikel (refereegranskat)abstract
- In greenhouse organic horticulture there is a great challenge in supplying the crop with adequate amounts of nutrients at the right stage of crop development. This has been identified as one of the main factors compromising yields in organic systems as compared with conventional hydroponic systems based on the use of synthetic fertilisers. In organic systems, the supply of nutrients is reliant on microbial degradation of organic complexes, a process that is dependent on factors such as temperature, soil water content and pH. Different organic fertilisers will also have different characteristics with respect to mineralisation of nutrients. In order to evaluate different strategies for organic fertilisation in long-term greenhouse crops such as high-wire tomato crops, an experiment with three different treatments was performed. The different strategies evaluated were one based on blood meal, kalimagnesia and the commercial product Baralith Enslow (composed of clay and ground lucerne), one with poultry manure and kalimagnesia, and one with solid biogas digestate and kalimagnesia. A five-month tomato crop was grown. Lysimeter samples were taken from the growing media biweekly for monitoring of plant available nutrients. The results suggested that nitrogen was likely to have been the limiting factor for plant growth, however, the biogas digestate delivered mineralised nitrogen throughout the experiment.
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| 20. |
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| 21. |
- Bergstrand, Karl-Johan, et al.
(författare)
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End-of-day treatments as a way of controlling growth in ornamental pot plants
- 2020
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Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1296, s. 287-292
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Konferensbidrag (refereegranskat)abstract
- With the introduction of light emitting diode (LED) technology for greenhouse lighting, the possibility to apply narrow band light becomes available to the grower. With narrow band light, it is possible to target the different photoreceptors of the plant, and thus control plant growth and development. Applying a brief period of narrowband light at the end of the photoperiod (end-of-day lighting) has been suggested as a way to control growth with a low total input of electric energy. Controlling stem elongation is an important part of greenhouse horticulture, especially for ornamental crops but also for vegetable transplants. Chemical plant growth regulators are efficient and widely used for this purpose, but questioned from an environmental point of view and not compatible with organic practices. In a series of experiments, end-of-day treatments with different wavebands were applied to poinsettia plants in order to evaluate the concept and to establish the most suitable wavelength. Red (660 nm), green (525 nm), and white (continuous spectrum) LED lights were evaluated. End-ofday light was applied for one hour after the main photoperiod, at an intensity of 10 µmol m-2 s-1. A treatment without end-of-day light was used as the control treatment. The results displayed significant differences among treatments.
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| 22. |
- Bergstrand, Karl-Johan, et al.
(författare)
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Growth control of ornamental and bedding plants by manipulation of photoperiod and light quality
- 2016
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Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1134, s. 33-39
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Konferensbidrag (refereegranskat)abstract
- Altering the light regime is a sound and non-polluting way of controlling the growth of greenhouse-grown pot and bedding plants, and a promising way of eliminating the use of chemical plant growth regulators (PGRs), which are now becoming less available and more questioned by consumers. Modern greenhouses often have blackout screens, originally installed for flower regulation purposes but which can also be used for growth regulation. Modern light emitting diode (LED) light sources can be designed to provide narrow-band light (NBL), which can affect growth and elongation of plants if given in addition to natural sunlight, or as daylight extension (end-of-day or pre-day treatments). Two different approaches were used: short photoperiods in combination with pre-day and end-of-day NBL treatments, and short photoperiods combined with simultaneous addition of NBL and natural light. The plants used were Calibrachoa, Pelargonium, Euphorbia, and Chrysanthemum. A light regime with 620 nm light given before the period of natural light and 525 nm light given at the end of the natural light effectively controlled elongation in both Calibrachoa and Pelargonium. Supplementation of natural sunlight with a small portion of 660 nm light significantly reduced plant height in Euphorbia, but not in Chrysanthemum. It was concluded that management of photoperiod and light quality is very promising for replacing PGRs within greenhouse production of ornamental and bedding plants.
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| 23. |
- Bergstrand, Karl-Johan, et al.
(författare)
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Högtrycksnatriumlampan duger än
- 2013
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Ingår i: Trädgårdsnytt. - 0049-4356. ; 67, s. 26-27
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 24. |
- Bergstrand, Karl-Johan, et al.
(författare)
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Liquid anaerobic digestate as sole nutrient source in soilless horticulture – or spiked with mineral nutrients for improved plant growth
- 2022
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Ingår i: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Digestate from biogas production high in plant-available macro- and micro-nutrients could replace mineral fertilizer in protected (soilless) horticulture. Previous uses of digestate have shown that low concentrations of plant-available phosphorus (P) and sulfur (S) may be limiting factors for growth when using digestate as the sole fertilizer. In this study, digestate collected from a municipal biogas plant in Sweden was nitrified in a moving-bed biofilm reactor prior to its use as fertilizer. A greenhouse pot trial with pak choi grown in peat-based growing medium was established to assess the (i) macro- and micro-nutrient availability in the digestate, with particular focus on P and S and (ii) the effect of amending the digestate solution with nutrients considered to be lacking [P, S, magnesium (Mg), manganese (Mn), boron (B), and molybdenum (Mo)]. The results showed that plants fertilized with raw digestate suffered from S and B deficiency and early P deficiency. Supplementing the digestate with nutrients originating from mineral salts resulted in sufficient plant tissue concentrations of all elements except S. The marketable yield was similar to that achieved using standard mineral fertilizer and the dry matter yield was 17% higher. In the light of the present results, the use of nitrified digestate in soilless plant production seems like a fruitful way forward to recycle organic nutrients from waste streams. In the case where a strict organic protocol is not needed, amendment with inorganic nutrients may be a way to increase the utilization of organically derived nutrients.
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| 25. |
- Bergstrand, Karl-Johan, et al.
(författare)
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Methods for measuring nutrient mineralization in growing media with organic fertilizers incorporated
- 2021
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Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; , s. 87-92
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Konferensbidrag (refereegranskat)abstract
- The use of organic nutrient sources is mandatory when producing plants according to organic standards. As the nutrient release from organic fertilizers is depending on microbial processes, they are in turn affected by factors such as moisture content, temperature, and pH. This makes mineralization hard to control and predict, and lacking synchronization between mineralization and crop demand is a major problem when using organic fertilizers (Bi et al., 2010; Burnett et al., 2016; Rosen and Allan, 2007) affecting crop productivity and potentially leading to decreased nutrient use efficiency and leaching. This fact invokes the need for analytical methods offering possibilities to predict nutrient availability during the crop cycle. However, as of today, there is a lack in standardized methods for characterization of nutrient release patterns from organic fertilizers. Also methods for analysis of horticultural growing media are not internationally standardized (Baumgarten, 2005), although incubation methods for N analysis have been suggested (Thorup-Kristensen, 1994). There are numerous different extraction methods for analysis of growing media which will provide fundamentally different values. Also for plant analysis, a number of different methods such as total analysis, plant sap analysis, and non-invasive optic methods are applied to scrutinize plant nutrient status. In the this paper, an attempt was made to track nutrient uptake from organically bound, to plant available in the peat-based growing medium, to uptake in the plant using different analysis methods. The overall objective was to develop a protocol to assess nutrient release from organic fertilizers.
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| 26. |
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| 27. |
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| 28. |
- Bergstrand, Karl-Johan, et al.
(författare)
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Plant developmental consequenses of lighting from above or below in the production of Poinsettia
- 2015
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Ingår i: European Journal of Horticultural Science. - 1611-4426 .- 1611-4434. ; 80, s. 51-55
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Tidskriftsartikel (refereegranskat)abstract
- Artificial light is used for many horticultural crops produced in greenhouses, not least ornamental pot plants. New technologies such as LEDs will possibly replace high intensity discharge lamps as the main technology for lighting in horticulture. However, LEDs are quite different from discharge lamps as regards the handling of waste heat. They have low output of radiant heat, but the waste heat is produced in the fixture and must be cooled away using fans or heat sinks. The low radiant heat will result in lower leaf temperature in the crop, possibly prolonging production time. LED fixtures are often voluminous due to the need for cooling systems, creating large shade effects when installed at the top of the greenhouse. To overcome these issues, this greenhouse study tested placing the light source, in the form of LED bars, under the crop, thus illuminating the abaxial side of the leaves. The results showed that the growth and elongation of the Euphorbia plants was similar irrespective of whether the light was supplied at the abaxial or adaxial side of the leaves. The air temperature within the canopy increased when the light source was placed within the canopy and fresh weight, dry weight and bract length of the bract also increased compared with when the same light was supplied from above, probably due to the higher temperature. Placing LED light sources below the canopy of potted ornamentals was found to be a feasible solution for supplying supplementary light.
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| 29. |
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| 30. |
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| 31. |
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| 32. |
- Bergstrand, Karl-Johan, et al.
(författare)
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Utilizing Anaerobic Digestates as Nutrient Solutions in Hydroponic Production Systems
- 2020
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Ingår i: Sustainability. - : MDPI AG. - 2071-1050. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Moving food production into the urban and peri-urban areas is one way of facilitating a closed-loop approach, integrating waste handling with food production in order to recirculate nutrients and at the same time reduce the use of mined and fossil resources in the production. Using anaerobic digestion as a way of converting urban wastes to an energy source (methane) and a nutrient-rich biodigestate with subsequent use as fertilizer for food production seems like a feasible approach. However, utilizing urban wastes in plant production systems implies some challenges, such as high salinity of the waste, imbalanced composition of nutrients, and abundance of less favorable forms of nitrogen. In a series of experiments, these problems were addressed. Vegetables (Pak Choi) were cultivated hydroponically in a controlled climate. Experiments included increased salinity, elevated levels of nitrite, and different concentrations of the biogas digestate-based nutrient solution, with mineral based solutions as controls. In general, the mineral controls yielded around 50% higher fresh biomass than the organic solutions. However, the quality of the produce with respect to content of secondary metabolites such as vitamins was enhanced when the plants were cultivated with organic nutrient solutions. Increasing the concentration of NaCl to 241 mg Cl L−1 did not negatively affect plant performance. Increasing the concentration of nitrite negatively affected plant growth, with reductions in biomass production by up to 50%. Given this well-functioning nitrification process that did not result in high nitrite concentrations, the use of anaerobic digestates seems feasible for hydroponic production of vegetables.
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| 33. |
- Bergstrand, Karl-Johan, et al.
(författare)
-
Utnyttja belysningen effektivt
- 2015
-
Ingår i: LTV-fakultetens faktablad.
-
Annan publikation (populärvet., debatt m.m.)abstract
- I norra Europa är ljuset helt otillräckligt för odling under vinterhalvåret och ibland även på sommaren. Artificiell belysning har därför blivit allt vanligare inte bara vid odling av småplantor och krukväxter utan även för året-runt-produktion av olika grönsaker i växthus. Utvecklingen har gått från glödlampor, neonrör och kvicksilverlampor via metallhalogen till högtrycksnatriumlampor (HPS) som är dominerande än idag alltsedan 1970-talet. Stigande energipriser och ökande krav på miljöhänsyn har gjort att det idag finns ett stort behov av att effektivisera användandet av belysning i växthus. Tekniken utvecklas stadigt, HPS-lamporna har undan för undan fått allt bättre effektivitet med införandet av 600 och 1000 W lampor samt elektroniska drivdon. Dessutom har helt nya lamptyper som t.ex. LED-lampor och plasmalampor kommit på marknaden. Det finns dock mycket man kan göra för att effektivisera sin användning av belysning utan att nödvändigtvis göra en dyr investering i att byta hela utrustningen.
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| 34. |
- Bergstrand, Karl-Johan, et al.
(författare)
-
Ökade utsläpp med krav på ekologiskt
- 2019
-
Ingår i: Dagens nyheter. - 1101-2447. ; , s. 04-04
-
Tidskriftsartikel (populärvet., debatt m.m.)
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| 35. |
- Bodin, Hristina, 1977-, et al.
(författare)
-
Effects of biopellets composed of microalgae and fungi on cadmium present at environmentally relevant levels in water
- 2017
-
Ingår i: International journal of phytoremediation. - : Taylor & Francis: STM, Behavioural Science and Public Health Titles. - 1522-6514 .- 1549-7879. ; 19:5, s. 500-504
-
Tidskriftsartikel (refereegranskat)abstract
- Removal of cadmium (Cd) present at low levels (1 µg L−1) in water was investigated using three different microorganism treatments: the microalga Chlorella vulgaris, the fungus Aspergillus niger and for the first time biopellets composed of C. vulgaris and A. niger. After 5 days, all microorganism treatments resulted in significantly lower Cd concentrations compared with the control. Biopellets treatment resulted in significantly lower pH values than other microorganism treatments, indicating that the biopellets should be investigated further for their water treatment capacity, since pH is a factor affecting the fate of numerous pollutants in water. Use of biopellets as a method to simplify harvesting of microalgae from water is also suggested.
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| 36. |
- Bodin, Hristina, et al.
(författare)
-
Effects of biopellets composed of microalgae and fungi on cadmium present at environmentally relevant levels in water
- 2017
-
Ingår i: International Journal of Phytoremediation. - : Informa UK Limited. - 1522-6514 .- 1549-7879. ; 19, s. 500-504
-
Tidskriftsartikel (refereegranskat)abstract
- Removal of cadmium (Cd) present at low levels (1 mu g L-1) in water was investigated using three different microorganism treatments: the microalga Chlorella vulgaris, the fungus Aspergillus niger, and for the first time biopellets composed of C. vulgaris and A. niger. After 5days, all microorganism treatments resulted in significantly lower Cd concentrations compared with the control. Biopellets treatment resulted in significantly lower pH values than other microorganism treatments, indicating that the biopellets should be investigated further for their water treatment capacity, since pH is a factor affecting the fate of numerous pollutants in water. Use of biopellets as a method to simplify harvesting of microalgae from water is also suggested.
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| 37. |
- Böhlenius, Henrik, et al.
(författare)
-
Differences in Al sensitivity affect establishment of Populus genotypes on acidic forest land
- 2018
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13
-
Tidskriftsartikel (refereegranskat)abstract
- Forest lands hold great potential for Populus plantations, but in native boreal forests, soils normally have low pH and thus higher levels of aluminum ions (Al3+ and hydroxides). Aluminum (Al) is one of the major factors limiting plant growth on these soils by inhibiting root growth, thus reducing water and nutrient uptake and slowing growth. There is a large variation in Al resistance both among and within species. In this study, growth responses of greenhouse-grown hybrid aspen (P. tremula x tremuloides) and poplar (P. trichocarpa hybrids) were monitored in relation to changes in Al concentrations. In quartz sand, hybrid aspen was more tolerant to exogenous application of Al than P. trichocarpa hybrids. This difference in Al-tolerance was further confirmed by hematoxylin staining of the roots, with hybrid aspen displaying less staining after Al treatment than poplar clones. When planted on forest land with low pH, hybrid aspen increased growth after planting and showed low mortality. This was not the case for poplar clones; plant height decreased after planting and mortality increased. Together, our results suggest that differences in initial growth and survival on forest land among hybrid aspen and the tested poplar clones may be connected to differences in Al tolerance. Our findings that staining with hematoxylin can identify Al-tolerant Populus genotypes may help identify Al-tolerant genotypes suitable for forest land.
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| 38. |
- Böhlenius, Henrik, et al.
(författare)
-
Growth response of hybrid aspen (Populus × wettsteinii) and Populus trichocarpa to different pH levels and nutrient availabilities
- 2016
-
Ingår i: Canadian Journal of Forest Research. - : Canadian Science Publishing. - 0045-5067 .- 1208-6037. ; 46, s. 1367-1374
-
Tidskriftsartikel (refereegranskat)abstract
- Populus plantations are mainly established on agricultural land, but natural forests soils typically have lower pHs and nutrient contents. In this study, growth responses of two commonly used Populus genotypes, hybrid aspen (Populus x wettsteinii Hamet-Ahti) and black cottonwood (Populus trichocarpa Torr. & A. Gray ex Hook.), were monitored in the greenhouse in relation of changes in pH and fertilizer levels in quartz sand and forest moraine soil. In quartz sand, changes in pH had no impact on growth or mortality of the two species. In forest soils, the lowest pH values, i.e., 3.5 and 4.0, caused plant mortality for P. trichocarpa but not for P. x wettsteinii. Growth optimum of P. trichocarpa occurred at a pH range of 5.5-6.5, whereas P. x wettsteinii showed a broader growth optimum at a pH range of 4.0-7.0. Fertilization expanded the pH range of optimum growth for P. trichocarpa but not for P. x wettsteinii. In both species, foliar content of nitrogen and potassium content increased after fertilization, whereas the foliar content of phosphorus was similar to unfertilized plants. Our results suggest that differences in tolerance to low pH values between P. x wettsteinii and P. trichocarpa might be connected to tolerance against aluminum. These findings may improve future establishment methods and identification of poplar genotypes suitable for forest land.
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| 39. |
- Böhmer, Jens, 1981, et al.
(författare)
-
Absolute Quantification of Donor-Derived Cell-Free DNA in Pediatric and Adult Patients After Heart Transplantation: A Prospective Study.
- 2023
-
Ingår i: Transplant international : official journal of the European Society for Organ Transplantation. - 0934-0874 .- 1432-2277. ; 36
-
Tidskriftsartikel (refereegranskat)abstract
- In this prospective study we investigated a cohort after heart transplantation with a novel PCR-based approach with focus on treated rejection. Blood samples were collected coincidentally to biopsies, and both absolute levels of dd-cfDNA and donor fraction were reported using digital PCR. 52 patients (11 children and 41 adults) were enrolled (NCT03477383, clinicaltrials.gov), and 557 plasma samples were analyzed. 13 treated rejection episodes >14days after transplantation were observed in 7 patients. Donor fraction showed a median of 0.08% in the cohort and was significantly elevated during rejection (median 0.19%, p < 0.0001), using a cut-off of 0.1%, the sensitivity/specificity were 92%/56% (AUC ROC-curve: 0.78). Absolute levels of dd-cfDNA showed a median of 8.8 copies/mL and were significantly elevated during rejection (median 23, p = 0.0001). Using a cut-off of 7.5 copies/mL, the sensitivity/specificity were 92%/43% for donor fraction (AUC ROC-curve: 0.75). The results support the feasibility of this approach in analyzing dd-cfDNA after heart transplantation. The obtained values are well aligned with results from other trials. The possibility to quantify absolute levels adds important value to the differentiation between ongoing graft damage and quiescent situations.
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| 40. |
- Caspersen, Siri, et al.
(författare)
-
Blueberry-Soil interactions from an organic perspective
- 2016
-
Ingår i: Scientia Horticulturae. - : Elsevier BV. - 0304-4238 .- 1879-1018. ; 208, s. 78-91
-
Tidskriftsartikel (refereegranskat)abstract
- Demand for organic blueberries has risen in response to consumers' interest in healthy eating and greater awareness of the environment. Although organic production systems share many challenges with conventional systems, they have specific limitations and questions. Synchronisation of plant nutrient demand with the release of mineral nutrients from organic nutrient sources presents a particular challenge for the organic grower. In this paper we address belowground challenges in blueberry production from an organic perspective, such as soil properties and amendments as well as the choice of mulching material and organic fertilisers. We also address potential toxicity problems for blueberries associated with high concentrations of aluminium and manganese as well as salt stress. Symbiosis with ericoid mycorrhizal fungi is of potential interest in organic blueberry production as the fungi may improve plant access to nutrients from organic sources. The effects of management factors and limitations associated with the commercial utilisation of the symbiosis are also discussed.
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| 41. |
- Caspersen, Siri, et al.
(författare)
-
Nutrient challenges with solid-phase anaerobic digestate as a peat substitute-Storage decreased ammonium toxicity but increased phosphorus availability
- 2023
-
Ingår i: Waste Management. - 0956-053X .- 1879-2456. ; 165, s. 128-139
-
Tidskriftsartikel (refereegranskat)abstract
- The solid fraction (SD) obtained after liquid - solid separation of anaerobic digestate is interesting as a potential fertilizer as well as a peat substitute in horticultural growing substrates. We investigated the effect of incubation of the SD obtained by screw-press separation of digestate produced from food waste and plant residues on potentially plant available mineral nutrients and plant growth. The NH4-N concentration was initially > 1000 mg L-1 but rapidly decreased, probably due to NH3 emission promoted by a high initial pH. No nitrate was detected during the first four weeks of incubation. The concentrations of potentially available P and Mg were closely related and strongly increased during incubation. The effect of adding 20 or 30 vol% of SD to a peat-based growing substrate on the growth of basil and lettuce was investigated before and after the incubation period. With the unincubated SD, the initial substrate NH4-N of 200-300 mg L-1 was potentially phytotoxic. Plant growth response ranged from inhibition to stimulation, probably reflecting variation in substrate ammonium status. After 96 days of incubation, ammonium concentrations had decreased with > 50% and basil growth was generally positively affected by addition of incubated SD. However, available P concentrations of 140-210 mg L-1 in the incubated substrates posed a high risk of P leakage. In conclusion, storage greatly reduced NH4-N con-centrations and phytotoxicity when the SD was used as a partial substituent for peat in a horticultural growing substrate. Measures are needed, however, to limit available P concentrations in high-P solid digestate fractions.
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| 42. |
- Caspersen, Siri, et al.
(författare)
-
Organic production systems in Northern highbush blueberries
- 2013
-
Ingår i: NJF Report. - 1653-2015. ; 9, s. 141-142
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The production of highbush blueberries is increasing worldwide. Organic production of blueberries in Sweden is presently very limited but is expected to have a great potential to expand as the berries are popular and have a good shelf life. The fact that blueberries require acid soils raises several questions concerning suitable substrates in combination with mycorrhizal inoculation and fertilization in organic production systems. Field and pot experiments have been established during 2011 and 2012 with the aim of developing a sustainable production system for high quality organic blueberries. After the second experimental year, total fruit yields were similar for plants grown in a plastic tunnel and in the open field. Yields were not affected by the addition of 10% forest soil to the peat-based substrate. Inoculation with ericoid mycorrhizal fungi had little effect on shoot length in a greenhouse pot experiment. Blueberries may be particularly suitable for organic production as the need for fertilizers is low combined with a relatively low disease pressure on the blueberry crop in the Nordic countries. The Swedish blueberry production might be expected to expand in the near future. The development of a successful and resource-efficient growing system for organic blueberries may encourage new blueberry growers to chose organic production.
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| 43. |
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| 44. |
- Ekelöf, Joakim, et al.
(författare)
-
Potato yield response to foliar application of phosphorus as affected by soil moisture and available soil phosphorus
- 2012
-
Ingår i: Acta Agriculturae Scandinavica, Section B - Soil and Plant Science. - : Informa UK Limited. - 0906-4710 .- 1651-1913. ; 62, s. 637-643
-
Tidskriftsartikel (refereegranskat)abstract
- Foliar application of phosphorus (P) may be a supplementary treatment to sustain adequate P-status of potato (Solanum tuberosum L.). However, the prediction of the potential benefits of foliar P supply is difficult, since several factors, such as weather conditions and plant P-status influence the effects. We determined the impact of soil moisture and soil P-supply on the responsiveness to foliar P-application under controlled environmental conditions. Plant dry matter yields, P-accumulation and phosphorus use efficiency (PUE) with or without foliar application were determined at five soil P-levels in combination with two soil moisture levels. The results suggest that water status is of importance for the responsiveness to foliar P-application and may be related to diffusion of P through the leaf cells, which require a good water status. The PUE was significantly improved with irrigation while adding P to the soil decreased the PUE.
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| 45. |
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| 46. |
- Golovko, Oksana, et al.
(författare)
-
Organic micropollutants, heavy metals and pathogens in anaerobic digestate based on food waste
- 2022
-
Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 313
-
Tidskriftsartikel (refereegranskat)abstract
- Anaerobic digestate based on food waste is increasingly used as fertilizer in food production. This study examined the characteristics of anaerobic digestate based on food waste from three biogas plants in Sweden. The characterization included measurements of heavy metals (n = 7), chemicals of emerging concern (CECs), such as currently used drugs and pesticides (n = 133), and an extended range of food-borne pathogens, including two notable sporeformers and some widespread antibiotic-resistant bacteria. The amounts of Escherichia coli, enterococci, and Salmonella and the concentrations of the target heavy metals were all below the maximum accepted levels at all three locations studied. However, the spore-forming Bacillus cereus was found to be present at high levels in samples from all three biogas plants. Among the 133 CECs investigated, 48 were detected at least once, and the highest concentrations were found for pyroxidine, nicotine, caffeine, theobromine, and nicotine. The biofertilizers from the different biogas plants had similar CEC profiles, which indicate similarities in household waste composition and thorough mixing in the biogas plants. If this profile is found to be spatially and temporally consistent, it can help regulators to establish priority lists of CECs of top concern. Assuming increasing use of biofertilizers for food production in the future, it would be beneficial to have concentration limits for CECs Risk estimation based on risk quotients (RQs) indicated generally low environmental risks associated with application of biofertilizer to soils for food crop production. However, the toxicity of CEC mixtures needs to be considered when estimating the risks from application of biofertilizers on agricultural land or in other production systems.
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| 47. |
- Golovko, Oksana, et al.
(författare)
-
Uptake of perfluoroalkyl substances, pharmaceuticals, and parabens by oyster mushrooms (Pleurotus ostreatus) and exposure risk in human consumption
- 2022
-
Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 291
-
Tidskriftsartikel (refereegranskat)abstract
- Organic micropollutants (MPs) pose potential threats to environmental ecosystems and human health. This study investigated uptake of perfluoroalkyl substances (PFASs), pharmaceuticals, and paraben by edible oyster mushrooms (Pleurotus ostreatus), cultivated on spiked growth substrate. Concentrations of pharmaceuticals and paraben in substrate showed a decreasing trend over a 20-day harvesting period, whereas PFAS concentrations were variable over the harvesting period. However, only propylparaben, clarithromycin, and PFASs were detected in fruiting bodies of oyster mushroom. Uptake of PFASs by oyster mushroom fruit bodies was negatively correlated with perfluorocarbon chain length. An impact of MPs on fungal colonization was observed, with decreased respiration in treatments with the highest concentration of MPs, but production of fruiting bodies was not affected by exposure level. The potential human risk from ingestion of MPs was evaluated for oyster mushrooms exposed to the highest concentration of MPs in substrate, based on acceptable daily intake (ADI).
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| 48. |
- Hultberg, Malin, et al.
(författare)
-
Adding benefit to wetlands : valorization of harvested common reed through mushroom production
- 2018
-
Ingår i: Science of the Total Environment. - 0048-9697 .- 1879-1026. ; 637-638, s. 1395-1399
-
Tidskriftsartikel (refereegranskat)abstract
- Wetlands have been successfully implemented as water purification systems for removal of plant nutrients and can play a significant role in nutrient recycling, depending on use of the harvested biomass. In a constructed wetland in southern Sweden examined in this study, assimilation of plant nutrients in wetland biomass corresponded to 234 kg/ha nitrogen, 22.8 kg/ha phosphorus, and 158 kg/ha potassium in the study year (2016). The harvested biomass, composed exclusively of common reed, was evaluated as a substrate for production of oyster mushrooms, one of the most widely produced edible mushrooms in the world. The biological efficiency of the substrate was 138 ± 10%, corresponding to production of 1.4 kg mushrooms (fresh weight) based on 1 kg reed (dry weight). The fruiting bodies had high quality, with total protein concentration 18.3 ± 2.8% and very low levels of contaminating heavy metals. Thus, nutrient assimilation in wetland biomass not only decreases the risk of eutrophication in recipient waters, but can be utilized for direct production of high-quality food. The biomass remaining after mushroom production, composed of mycelium and partly degraded wetland biomass, has potential for use in ruminant feed, i.e., as roughage.
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| 49. |
- Hultberg, Malin, et al.
(författare)
-
Adding benefit to wetlands - Valorization of harvested common reed through mushroom production
- 2018
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 637-638, s. 1395-1399
-
Tidskriftsartikel (refereegranskat)abstract
- Wetlands have been successfully implemented as water purification systems for removal of plant nutrients and can play a significant role in nutrient recycling, depending on use of the harvested biomass. In a constructed wetland in southern Sweden examined in this study, assimilation of plant nutrients in wetland biomass corresponded to 234 kg/ha nitrogen, 22.8 kg/ha phosphorus, and 158 kg/ha potassium in the study year (2016). The harvested biomass, composed exclusively of common reed, was evaluated as a substrate for production of oyster mushrooms, one of the most widely produced edible mushrooms in the world. The biological efficiency of the substrate was 138 +/- 10%, corresponding to production of 1.4 kg mushrooms (fresh weight) based on 1 kg reed (dry weight). The fruiting bodies had high quality, with total protein concentration 18.3 +/- 2.8% and very low levels of contaminating heavy metals. Thus, nutrient assimilation in wetland biomass not only decreases the risk of eutrophication in recipient waters, but can be utilized for direct production of high-quality food. The biomass remaining after mushroom production, composed of mycelium and partly degraded wetland biomass, has potential for use in ruminant feed, i.e., as roughage. (C) 2018 Elsevier B.V. All rights reserved.
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| 50. |
- Hultberg, Malin, et al.
(författare)
-
Benefits and drawbacks of combined plant and mushroom production in substrate based on biogas digestate and peat
- 2022
-
Ingår i: Environmental technology & innovation. - : Elsevier BV. - 2352-1864. ; 28
-
Tidskriftsartikel (refereegranskat)abstract
- Production of plants and mushrooms in substrate based partly on anaerobic digestate from biogas production (30%) and peat (70%) was studied in experiments performed using oyster mushroom (Pleurotus ostreatus) and basil (Ocimum basilicum). Biogas digestate was included in order to decrease use of peat and fertilizer. In separate experiments, combined greenhouse production of mushrooms and plants in fresh substrate, mushroom production in bags of fresh substrate or spent substrate from plant production, and plant production in spent substrate from mushroom production were studied. In terms of plant yield, positive impacts of combined culture were observed, with significantly higher yield of basil when mushroom spawn was added to fresh substrate at a concentration of 2% (p 0.04). Increasing the concentration to 10%, which was sufficient for fruiting body formation in parallel with plant production, did not increase basil yield compared with the control. When fresh substrate was partly replaced with spent substrate from mushroom production, significantly higher yield of basil was obtained (p 0.001). Mushroom production had an impact on the nutritional composition of the substrate, resulting in changes in nitrogen dynamics, a significant decrease in phosphorus concentration by 14% (p 0.001), and a change in extractable concentrations of five of 10 elements studied. In terms of mushroom yield, the impacts of combined production with plants were generally negative.
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