Svensk vinodling i norr?

Hur kommer den allt varmare morgondagen att påverka vår zonkarta? I ett globalt perspektiv är det idag varmare än det har varit på 3 000 år

Nutrient utilization and growth of tomato crops fertilized with solid anaerobic digestate

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

Modifiering av biogödsel för ökad användning i krukodling och för minskad torvanvändning

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

Nutrient challenges with solid-phase anaerobic digestate as a peat substitute-Storage decreased ammonium toxicity but increased phosphorus availability

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

Utilizing Anaerobic Digestates as Nutrient Solutions in Hydroponic Production Systems

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

Benefits and drawbacks of combined plant and mushroom production in substrate based on biogas digestate and peat

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

Production of oyster mushroom (Pleurotus ostreatus) on sawdust supplemented with anaerobic digestate

Anaerobic digestion of organic waste results in production of biogas and a nutrient-rich digestate that has an established use as fertilizer in plant production. This study evaluated use of anaerobic digestate based on a high concentration of organic household waste as a fertilizer in sawdust-based production of oyster mushrooms (Pleurotus ostreatus). Inclusion of 0.5 L of anaerobic digestate (AD) per kg sawdust gave similar productivity in terms of biological efficiency (79.5 +/- 5.4 %), and protein concentration (24.7 +/- 2.4 % of dry weight (dw)) as standard mushroom substrate (78.1 +/- 5.3 %, and 21.9 +/- 3.0 % of dw, respectively). However, mushroom growth was impaired at the highest concentration of anaerobic digestate tested, 1 L digestate per kg dw sawdust. Comparison of the AD-fertilized substrate with a mushroom substrate with standard components (sawdust, wheat bran, calcium sulfate) and with similar C/N-ratio revealed some differences in elemental composition of the fruiting bodies, with an major increase in sodium concentration for the AD-fertilized substrate compared with the standard substrate (413.3 +/- 28.9 and 226.7 +/- 30.6 mg kg(-1) dw, respectively). This difference can be explained by high sodium concentration in the anaerobic digestate, most likely due to inclusion of food scraps from households and restaurants in the biodigester feedstock. Screening of both substrates for a total of 133 micro -pollutants revealed that total sum of micropollutants was significantly higher in the AD-fertilized substrate (258 +/- 12 ng/g dw substrate) than in the standard substrate (191 +/- 35 ng/g dw substrate). Nitrogen losses during preparation of the AD-fertilized substrate were negligible

Ekologisk odling av trädgårdsblåbär, erfarenhet från försöksodling på Rånna försöksstation

För att lyckas med ekologisk odling av trädgårdsblåbär krävs att det finns ett hållbart substrat med lågt pH där buskarna trivs. Tillförd växtnäring ska ha organiskt ursprung och bör vara enkel att tillföra. Sjukdomar och skadegörare måste kontrolleras med ekologiskt accepterade metoder och ogräs måste hållas borta. I ett försöksprojekt på SLU Rånna försöksstation har en ekologisk blåbärsodling, på friland och i tunnel, dokumenterats under fem skördeår

Biogödsel som näringskälla vid hydroponisk odling - nitrifiering och pH

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