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- Asp, Håkan, et al.
(author)
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Anaerobic digestate as peat substitute and fertiliser in pot production of basil
- 2022
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In: Biological Agriculture & Horticulture. - : Informa UK Limited. - 0144-8765 .- 2165-0616. ; 38, s. 247-257
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Journal article (peer-reviewed)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. |
- Caspersen, Siri, et al.
(author)
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Blueberry-Soil interactions from an organic perspective
- 2016
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In: Scientia Horticulturae. - : Elsevier BV. - 0304-4238 .- 1879-1018. ; 208, s. 78-91
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Journal article (peer-reviewed)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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| 5. |
- Caspersen, Siri
(author)
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Bättre fosforutnyttjande med effektiva löksorter?
- 2016
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In: LTV-fakultetens faktablad.
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Other publication (pop. science, debate, etc.)abstract
- Ett effektivt utnyttjande av fosforgödselmedel är angeläget eftersom fosfor är en begränsad och icke förnybar resurs. Fosforförluster från odlad mark är dessutom en viktig orsak till övergödning och algblomning i Östersjön. Lök har ett grovt rotssystem och kräver relativt mycket fosforgödsel. I det här projektet har olika löksorters förmåga att ta upp och utnyttja fosfor jämförts och sorternas egenskaper har studerats. Kunskap om skillnader i fosforeffektivitet mellan sorter kan användas för att optimera tillförseln av fosfor vid odling av frilandsgrönsaker.
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| 6. |
- Caspersen, Siri
(author)
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Closing the loop on human urine: Plant availability of zeolite-recovered nutrients in a peat-based substrate
- 2018
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In: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 211, s. 177-190
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Journal article (peer-reviewed)abstract
- Recycling mineral nutrients from household wastewater is a central step in the development of a circular economy based society. The objective of this study was to evaluate plant availability of mineral elements and plant performance in a peat substrate containing nutrient-enriched zeolite (NEZ) obtained by nutrient recovery from human urine in a source separated wastewater system. Substrate content of potentially available mineral nutrients was determined by CaCl2/DTPA-extraction during a 12 weeks incubation experiment for 20:80 (R20) and 30:70 (R30) volume % of NEZ:sphagnum peat, limed R20 (R20L), and 20:80 vol% of unloaded zeolite:sphagnum peat (Z20). Plant availability of mineral elements from R20, R20L, R30 and Z20 was compared with conventionally fertilised sphagnum peat (P100) for sunflower (Helianthus annuus L.) cv. ‘Topolino’ in a pot experiment. Recovery of nutrients in a potentially available form in the R20 substrate after 12 weeks was 3% (K), 23% (N, P), 34% (Mg) and 90% (S). Liming increased the recovery of mineral N to 39%, suggesting that nitrification was an important driver for the release of NH4+. For R20, estimated recovery of urine-derived N in sunflower shoots was 30–36%. Shoot biomass was similar in R20 and in conventionally fertilised peat (P100). However, P100 plants had more leaves and flowers+buds. Initial addition of ammonium phosphate or supplemental fertilisation with a complete nutrient solution increased flower+bud number in R20. For the NEZ-treatments, Cu and B shoot concentrations were in the low or marginal range while Zn and Mn were high or in excess. Shoot growth and nutrient uptake of sunflower were highly restricted in the unloaded zeolite control (Z20). We conclude that 20% NEZ in a peat substrate was effective as a macronutrient source for sunflower, producing similar biomass as in conventionally fertilised peat. However, micronutrient balance and early P supply may need to be adjusted for optimal plant performance.
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| 8. |
- Caspersen, Siri
(author)
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Fosfor – återföring från avlopp till åker med slagg
- 2019
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In: LTV-fakultetens faktablad.
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Other publication (pop. science, debate, etc.)abstract
- Fosfor är ett viktigt växtnäringsämne som är helt avgörande för tillväxt och skörd. Inom en överskådlig framtid kommer det att bli brist på fosfor. Samtidigt orsakar fosforn övergödning om den hamnar i känsliga vattendrag. Enskilda avlopp är en av källorna till övergödning, men de kan också ses som en potentiell fosforkälla. I ett krukförsök har vi undersökt om avloppsbehandlad slagg från stålproduktion kan användas som gödselmedel, samt hur slaggen påverkar växternas upptag av olika mineralämnen.
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