Does Loading Ammonium to Sorbents Affect Plant Availability in Soil?

Sorption to cheap sorbents can be used to concentrate nutrients from liquid waste streams and make them into fertilisers. In this study we assess how plant available is ammonium nitrogen (N) sorbed to three sorbents, and if the potential for greenhouse gas (GHG) emissions after a non-growing season is affected by sorption. Ammonium-N labelled with N15 was sorbed to biochar, bentonite and zeolite. Treatments where N was sorbed and where N and sorbents were applied separately were tested in a pot experiment with wheat, and soil samples were then frozen and dried to simulate non-growing seasons. After thawing and re-wetting, GHG emissions from the soil were assessed. There was no difference between sorption treatments in biomass or N uptake or fertiliser N left in the soil, and little difference between sorption treatments in gas emissions after the non-growing seasons was seen. We conclude that ammonium applied sorbed to these sorbents is as plant available as ammonium applied the conventional way. GHG emissions at the beginning of the next season are also not affected by ammonium applied sorbed.Does Loading Ammonium to Sorbents Affect Plant Availability in Soil?publishedVersio

Anaerobic digestion affecting nitrous oxide and methane emissions from the composting process

Composting and anaerobic digestion are the most common ways to treat organic residues. Sometimes the organic rest after anaerobic digestion is also composted. In this study we investigated greenhouse gas emissions from composting raw food waste compared to composting solid digestate of food waste. Cumulative methane emissions over 3 weeks were found to be almost 12 times higher from composting digested food waste than from raw food waste suggesting that the microbial community transferred from the anaerobic digestion to the compost process enhanced these emissions. Cumulative nitrous oxide emissions were also higher when composting solid digestate was compared to composting raw food waste, but the global warming potential was mostly driven by the impact of methane emissions. In conclusion, methane production during digestate composting can be high, therefore eliminating methane producing microbes in digestate before composting could be a promising way to reduce greenhouse gas emissions.acceptedVersio

Growth, yield and fruit quality of tomato Solanum lycopersicum L grown in sewage-based compost in a semi-hydroponic cultivation system

Purpose: Due to environmental concerns, there is a demand to reduce the use of peat as a growing medium for horticultural crops. Simultaneously, there is an interest to recycle organic waste materials in the form of compost. This study aimed to document effects on growth, yield, and fruit quality of tomato plants when cultivated in a sewage digestate-based compost in a subirrigation container system. Materials and methods: The compost used in this experiment consisted of 30% hygienised sewage digestate from biogas extraction and 70% garden waste. The treatments were 100% compost, a peat mix and mixtures of the two in 25/75, 50/50 and 75/25 ratios. Results and conclusion: Considering the contrast in chemical and physical properties of the treatments, variations in growth, yield and quality were expected. The plants differed in leaf area and number of leaves, but there were no differences in yield or quality of the tomato fruits. It is assumed that this is in great part due to the remediating effects of subirrigation with an ideal nutrient solution, and the use of pre-established plants. Further research should focus on benefits of this cultivation system for use in sustainable horticulture in combination with recycled organic waste.publishedVersio

Phosphorus availability in residues as fertilizers inorganic agriculture

Phosphorus (P) should be recycled from organic wastes as much as possible, and input is needed in stockless organic agriculture. Here we assessed 7 organic residues and compared them to mineral P fertilizer and rock phosphate as fertilizer for barley. P availability in the mixtures and residual P availability were also assessed by DGT. The best availability was found in digested liquid manure followed by wood ash, fish sludge, composted solid manure and composted food waste. Meat and bone meal, the commercially available product ladybug and rock phosphate had low P availability at the same level as no P. Only wood ash had significant P available for the next crop. The pH level of the soil did not affect P availability for any of the P sources. DGT predicted P availability moderately well, as it measures P supply over a short period without any biological factors

Kompostens virkning i dyrket jord

Kompost produseres gjennom omdanning av organisk nedbrytbart materiale under god tilgang på luft. Prosessen kompostering benyttes for å omdanne det organiske materialet i avfall til en mer stabil ressurs. Varmen som produseres i prosessen bidrar til å redusere innholdet av sykdomsfremkallende mikroorganismer. En vellykket komposteringsprosess gir mindre dårlig lukt som stammer fra forråtnelsesprosesser. Moden kompost av høy kvalitet kjennetegnes ved at den er stabil og derfor ikke gir påvisbar varmeutvikling ved videre lagring, at den lukter «jord», at den er passe fuktig og at den ikke inneholder skadelige forbindelser eller smitte. Kompost er først og fremst egnet brukt til jordforbedring, men har vanligvis også en viss gjødselvirkning

Does Loading Ammonium to Sorbents Affect Plant Availability in Soil?

Sorption to cheap sorbents can be used to concentrate nutrients from liquid waste streams and make them into fertilisers. In this study we assess how plant available is ammonium nitrogen (N) sorbed to three sorbents, and if the potential for greenhouse gas (GHG) emissions after a non-growing season is affected by sorption. Ammonium-N labelled with N15 was sorbed to biochar, bentonite and zeolite. Treatments where N was sorbed and where N and sorbents were applied separately were tested in a pot experiment with wheat, and soil samples were then frozen and dried to simulate non-growing seasons. After thawing and re-wetting, GHG emissions from the soil were assessed. There was no difference between sorption treatments in biomass or N uptake or fertiliser N left in the soil, and little difference between sorption treatments in gas emissions after the non-growing seasons was seen. We conclude that ammonium applied sorbed to these sorbents is as plant available as ammonium applied the conventional way. GHG emissions at the beginning of the next season are also not affected by ammonium applied sorbed

Greenhouse gas emissions from digestate in soil

Purpose Biogas residues, digestates, contain valuable nutrients and are therefore suitable as agricultural fertilizers. However, the application of fertilizers, including digestates, can enhance greenhouse gas (GHG) emissions. In this study different processes and post-treatments of digestates were analyzed with respect to triggered GHG emissions in soil. Methods In an incubation experiment, GHG emissions from two contrasting soils (chernozem and sandy soil) were compared after the application of digestate products sampled from the process chain of a food waste biogas plant: raw substrate, digestate (with and without bentonite addition), digestates after separation of liquid and solid phase and composted solid digestate. In addition, the solid digestate was sampled at another plant. Results The plant, where the solid digestate originated from, and the soil type influenced nitrous oxide (N2O) emissions significantly over the 38-day experiment. Composting lowered N2O emissions after soil application, whereas bentonite addition did not have a significant effect. High peaks of N2O emissions were observed during the first days after application of acidified, liquid fraction of digestate. N2O emissions were strongly correlated to initial ammonium (NH4+) content. Conclusion Fertilization with dewatered digestate (both fractions) increased N2O emission, especially when applied to soils high in nutrients and organic matter

Kompostens virkning i dyrket jord

Kompost produseres gjennom omdanning av organisk nedbrytbart materiale under god tilgang på luft. Prosessen kompostering benyttes for å omdanne det organiske materialet i avfall til en mer stabil ressurs. Varmen som produseres i prosessen bidrar til å redusere innholdet av sykdomsfremkallende mikroorganismer. En vellykket komposteringsprosess gir mindre dårlig lukt som stammer fra forråtnelsesprosesser. Moden kompost av høy kvalitet kjennetegnes ved at den er stabil og derfor ikke gir påvisbar varmeutvikling ved videre lagring, at den lukter «jord», at den er passe fuktig og at den ikke inneholder skadelige forbindelser eller smitte. Kompost er først og fremst egnet brukt til jordforbedring, men har vanligvis også en viss gjødselvirkning.publishedVersio

Greenhouse gas emissions from digestate in soil

Purpose Biogas residues, digestates, contain valuable nutrients and are therefore suitable as agricultural fertilizers. However, the application of fertilizers, including digestates, can enhance greenhouse gas (GHG) emissions. In this study different processes and post-treatments of digestates were analyzed with respect to triggered GHG emissions in soil. Methods In an incubation experiment, GHG emissions from two contrasting soils (chernozem and sandy soil) were compared after the application of digestate products sampled from the process chain of a food waste biogas plant: raw substrate, digestate (with and without bentonite addition), digestates after separation of liquid and solid phase and composted solid digestate. In addition, the solid digestate was sampled at another plant. Results The plant, where the solid digestate originated from, and the soil type influenced nitrous oxide (N2O) emissions significantly over the 38-day experiment. Composting lowered N2O emissions after soil application, whereas bentonite addition did not have a significant effect. High peaks of N2O emissions were observed during the first days after application of acidified, liquid fraction of digestate. N2O emissions were strongly correlated to initial ammonium (NH4+) content. Conclusion Fertilization with dewatered digestate (both fractions) increased N2O emission, especially when applied to soils high in nutrients and organic matter.publishedVersio