Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2024
Forfattere
Nicole AndersonSammendrag
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Forfattere
Nicole AndersonSammendrag
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Forfattere
Michel VerheulSammendrag
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Forfattere
Qiang Liu Haoyu Zhang Shuo Chen Yeqing Li Mahmoud Mazarji Lu Feng Junting Pan Hongjun Zhou Chunming XuSammendrag
Humic acids (HAs), whether naturally present in anaerobic digestion (AD) substrates or HAs newly formed during fermentation, can become inhibitory to methanogenesis as their concentrations reach certain levels. This study delved extensively into the mechanism underlying the alleviation of HAs inhibition in photo-AD by N-doped carbon quantum dots (NCQDs). These NCQDs were efficiently synthesized from straw using an environmentally friendly pretreatment method. Our proposed method harnessed the combined effect of light exposure and NCQDs, resulting in synergistic enhancement of the cumulative CH4 yield within the HA-inhibited AD system, achieving a remarkable yield of 293.7 ± 17.7 mL/g VS. In-depth analyses were conducted on the remaining dissolved organic matter (DOM) within digesters using 3D-EEM and ESI FT-ICR MS. Simultaneously, the remaining HAs were extracted and subjected to FT-IR analysis. The findings revealed that NCQDs effectively degraded humic acid-like components in DOM into smaller, more manageable micromolecules characterized by lower carbon numbers and reduced double bond equivalent. Additionally, under the influence of light, NCQDs promoted the degradation of aromatic components within HAs. These resulting micromolecules were made readily available for utilization by microorganisms, further contributing to methanogenesis. Furthermore, photoelectrochemical analysis and specific gene qPCR analysis revealed that the photoelectrons from NCQDs and HAs were received and transferred by Ech (electron acceptors) for methanogenesis. Remarkably, this methanogenesis pathway, akin to photosynthesis, played a pivotal and transformative role in the photo-AD system. This work comprehensively revealed the remarkable potential mechanism of semiconductors within the photo-AD system, offering profound insights that can catalyze the development of innovative AD reactors and semiconductor accelerators.
Sammendrag
Manure spreading often leads to nutrient losses with negative environmental impacts, especially in cold climates where harsh winters can affect grass sward density. Nutrient efficiency in cattle slurry depends on the plant coverage at the start of the growing season. To simulate winter damage variation, random mechanical disturbance was applied to a grass field. Aerial images were obtained and analysed using the Grasision® tool to estimate plant cover. Three fixed treatments with uniform cattle slurry and N fertilizer application across all plots, and two treatments adjusting slurry and N fertilizer based on autumn or spring plant coverage were tested. Above-ground yield was measured post-first and second cut. Adjusting N rates based on spring plant coverage or using a low N rate resulted in similar agronomic N use efficiency as high N application rates, albeit with lower dry matter yield.
Forfattere
Annette Folkedal SchjøllSammendrag
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Sammendrag
This study investigated the effects of substrates composed of various ratios of wood fiber and peat (0, 25, 50, 75, and 100% peat (v/v)) mixed with different amounts of lime (0, 2, 4, 6, and 8 g L−1) and start fertilizer (0, 2, and 4 g L−1 Multimix) on the growth and biomass accumulation of petunia (Petunia x hybrida Vilm ‘Finity F1 Purple’) and basil (Ocimum basilicum L. ‘Marian’) in an ebb-and-flow greenhouse system. Growth parameters included plant height, weight, canopy diameter, and chlorosis symptoms for petunia, along with substrate pH and EC measurements. Petunia showed optimal growth in substrates with higher peat content, while basil produced satisfactory biomass across a pH range of 5–7 regardless of substrate type. Optimal petunia cultivation in 100% wood fiber required a significant dose of start fertilizer without lime. Monitoring pH and EC using pour-through and press methods revealed a pH decrease in substrates with added start fertilizer, while substrates with higher wood fiber content were less acidic. Substrates with over 50% (v/v) wood fiber without lime showed a rapid pH increase over five weeks. The pour-through method generally underestimated EC values compared to the press method. These findings contribute to optimizing the wood fiber/peat blends for sustainable horticulture.
Forfattere
Carl-Fredrik Johannesson Jenni Nordén Holger Lange Hanna Marika Silvennoinen Klaus Steenberg LarsenSammendrag
Non-steady-state chambers are often used for greenhouse gas flux measurements, and while there are recommendations on how long to keep the chamber closed, it is less investigated to what extent the length of the chamber closure period affects the estimated flux rates and which closure periods may provide the most accurate linear and non-linear flux estimates. Previous studies have shown that the closure of non-steady-state chambers induces a non-linear concentration development inside the chamber, even across short chamber closure periods, and that both linear and non-linear flux estimates are impacted by the chamber closure period itself. Based on 3,159 individual soil CO2 and CH4 flux measurements, we analyzed how linear regression and Hutchinson and Mosier (1981) modeled flux estimates are affected by the length of the chamber closure period by increasing it in increments of 30 sec, with a minimum and maximum chamber closure period of 60 and 300 sec, respectively. Across all detected flux measurements, the effect of chamber closure period length varied between 1.4–8.0 % for linear regression estimates and between 0.4–17.8 % for Hutchinson–Mosier estimates, and the largest effect sizes were observed in high flux regions. While both linear regression and Hutchinson–Mosier based estimates decreased as the chamber closure period increased, we observed a clear convergence of flux estimates as shorter and longer chamber closure periods were used for linear regression and Hutchinson–Mosier based estimation, respectively. This suggests using closure periods as short as possible for linear regression flux estimation or ensuring long-enough closure periods to observe a stabilization of Hutchinson–Mosier flux estimates over time. This analysis was based on soil flux measurements, but because the perturbation of the concentration gradient is related to the non-steady-state chamber technique rather than the measured ecosystem component, our results have implications for all flux measurements conducted with non-steady-state chambers. Non-steady-state Static chamber Closure period Concentration gradient Hutchinson–Mosier Minimum detectable flux
Sammendrag
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Forfattere
Eva BrodSammendrag
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