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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2025

Abstract

Abstract Turfgrass winter kill due to freeze/thaw cycles and ice encasement (IE) is a problem on putting greens the Nordic countries. Our objectives were (1) to investigate how green coverage with impermeable plastic before IE affects soil temperature, O 2 and CO 2 concentrations, winter survival and spring recovery of creeping bentgrass (CRB), red fescue (RF), and annual bluegrass (AB) and (2) to explore how these turfgrasses are affected by snow and ice removal during the entire winter or parts of it. Six treatments were imposed on 5‐month‐old turf of the three species during the winters 2020/2021 and 2021/2022 at NIBIO Apelsvoll, Norway (60°42′ N). With an average soil temperature at 2‐cm depth of −0.9°C and the lowest O 2 concentrations around 5%, conditions under IE or plastic + IE treatments never became anoxic. On average for six treatments and 2 years, CRB and RF had significantly better winter survival (both 52%) than AB (25%). Turfgrass winter survival, spring color, and spring growth were significantly better (62% survival on average for species) with plastic between the grass and 10‐cm IE than with 10‐cm IE directly on the grass (23% survival). Snow and ice removal throughout the winter or before IE in early January improved turfgrass freezing tolerance in January but did not improve winter survival, green color, or spring growth compared with the control treatment with natural winter conditions. We conclude that putting greens in areas with unstable winters and risk for prolonged IE ought to be protected by impermeable plastic. Ventilation under the plastic may be necessary on old greens with more organic matter than in this experiment. On frozen uncovered greens, it is better to avoid prolonged IE by snow removal before rain or warm spell in December/early January than by mechanical ice removal in March.

Abstract

Diverse pedoclimatic zones lead to large variations in soil organic carbon (SOC). Key questions involve how much carbon the soil contains, what is its potential for more storage and whether levels are sufficient to maintain soil structure stability (SSS). We evaluate current SOC levels using ratios of clay/silt fractions to SOC, to identify potential SOC storage areas and to gauge likely SSS status. SOC retention is affected by clay and silt, which protect it from microbial activity. Hassink (1997) used the ratio of clay plus silt <20 µm (fines20) to SOC to indicate this relationship, whilst Dexter et al. (2008) used the ratio of clay to SOC. Jensen et al. (2019) found critical ratios for SSS to be ~10 for clay/SOC and ~20 for fines20/SOC, above which SSS is impaired and below which SOC is less likely to be retained. These ratios appear valid under Norwegian conditions, where greatest declines in SOC have been found in soils with high initial SOC levels and lowest declines in clay soils (Riley & Bakkegard 2008). After 28 years of a cropping system trial in eastern Norway (Riley et al. 2022), equilibrium between SOC gains and losses was at a fines20/SOC ratio of ~18, whilst in the same trial SSS declined sharply in an arable cropping system with a clay/SOC ratio >10, compared to systems with ratios of 6- 8. In western Norway, on grassland soils with generally low fines20/SOC ratios, SOC appears to be declining despite manure inputs, especially in cases with high initial SOC levels (Rittl et al. 2023). To obtain insight into the potential for SOC across Norway, data was used from a study in which SOC and soil texture was analysed on 600 fields in agricultural districts throughout the country. Results are grouped into 13 regions with relatively uniform climate and cropping within each. Greatest proportions of fields with high ratio levels were found in regions around Oslo and east of Oslofjord, with predominantly clay and silty clay loams, where 65% of fields had clay/SOC >10 and 80% had fines20/SOC >20. Proportions of fields with fines20/SOC >20 were somewhat lower west of Oslofjord (65%) and in central Norway (44%), where many soil textures are found, and in an inland region with predominantly silty soils (55%). Proportions of fields with high ratio levels were low in inland regions with loam soil, where 15-20% had clay/SOC >10 and 24% had fines20/SOC >20. All these regions are mainly arable, with some livestock, and mean SOC levels are <3,0%. In the predominantly grassland/livestock regions of southern, western and northern Norway, and in upland areas, the soils are mostly sandy and silty loams, and mean SOC levels are mostly >3,5%. In these regions, the proportion of fields with clay/SOC >10 was below 5% whilst that of fines20/SOC >20 was below 10%. Mean clay/SOC ratios were 1-3 and mean fines20/SOC ratios were 4-10. Arable land has thus greater potential for carbon storage than grassland, whilst at the same time increasing SSS and reducing erosion risk.

Abstract

Background and aims Cover crops are an important measure for carbon (C) sequestration in agriculture. However, little is known about the potential of cover crops to increase C under Nordic conditions and the efficiency of this measure over time. Here, we quantify the potential contribution of different cover crops to soil organic carbon (SOC) and organic matter fractions, and study how this is affected by the origin of the C input (aboveground or belowground residues). Methods We conducted a 13 CO 2 pulse-labelling experiment during the growing season of four cover crops adapted to Nordic conditions, representing different plant functional types. The assimilated 13 C was traced in soil during the following two years. We investigated the fate of cover crop C in two organic matter fractions, Particulate Organic Matter (POM) and Mineral-Associated Organic Matter (MAOM), known to have different persistence in soil. Results Carbon derived from aboveground residues decayed two to three times faster as compared to belowground C. Belowground C inputs were similar among cover crops despite their contrasting root traits and differences in root biomass C. Rhizodeposited-C was consistently the largest belowground C input. Cover crop species affected the quantity of POM-C and MAOM-C, but MAOM-C was preferentially formed from belowground C (ranging from 0.63 ± 0.2 to 0.25 ± 0.1 Mg MAOM-C ha −1 across different cover crops), regardless of the species. Conclusions Cover crop species that can combine large belowground biomass production with root traits that promote physical and physico-chemical protection of OM will contribute most effectively to the long-term SOC pool. These aspects need to be balanced with considerations related to agricultural management.

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Abstract

Agrivoltaics, also known as solar sharing or agri-PV, represents a pioneering con- cept that seeks to optimise land use by combining agriculture with photovoltaics on the same land area. While research and development on this topic have increased significantly, few studies address the issue in the Continental Subarctic Climate zone. In this paper, we report on the modelling and installation of a 48 kWp agrivoltaic system at the Skjetlein High School in Trondheim (Norway, lat. 63.34), which is currently the highest latitude system in the World, and we present the initial results of the impacts of the system on Timothy grass biomass. This work takes the first steps towards realising agrivoltaic opportunities for a broad area of Norwegian agriculture.

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Abstract

Pea (Pisum sativum L.) plays a central role for achieving the goal of increased self-sufficiency of plant-based protein for food and feed in Norway. This study characterized 36 pea genotypes of mainly Nordic and eastern European origin grown in a multi-environment field trial in Norway for various agronomic traits including grain and protein yield. The same accessions were also genotyped with a single nucleotide polymorphism (SNP) chip array to investigate the genetic diversity both at the phenotypic and genomic levels. Variance component (VC) analyses found that genotype (G) and genotype by year by location (G × Y × L) interaction VC were the main sources of variation for all the considered traits, with G × Y × L being strongly affected by the different climatic conditions which characterized the two test years. A further dissection of the genotype by environment interactions (GEI) through Additive Main effects and Multiplicative Interaction (AMMI), highlighted pea cultivars which outperformed the reference Norwegian variety Ingrid both in term of yield, protein content and protein yield. Measurements of genetic distance based on phenotypic and genomic data were significantly correlated and distinguished the material in three main clusters which were partially associated with their geographic origin. Overall, this work identified pea genotypes which can be successfully grown in Norway and used as source of genetic diversity for future breeding efforts targeting the Norwegian environment.