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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.

2026

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Abstract

This report examines how co-occurring non-native species can interact to create cumulative impacts on ecosystems. Non-native species may interact in additive, antagonistic, or synergistic ways. Through literature review, we found theoretical foundations and empirical examples showing that such interactions often occur. Synergistic interactions are of particular concern. Certain ecosystems appear particularly susceptible, including agricultural landscapes, urban environments, riparian systems, shipping-influenced marine areas, and islands with naïve fauna. We conclude that cumulative effects are ecologically important, and that it would be beneficial to incorporate multispecies interactions into risk assessments of non-native species in Norway.

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Abstract

Sustainable intensification technologies (SITs) are widely promoted across sub-Saharan Africa to improve productivity and reduce land degradation. However, their relationship with land use efficiency remains insufficiently understood. This study uses a translog stochastic frontier model and farm-level data from 372 smallholder maize farmers in northern Ghana to examine how SIT adoption is associated with technical land use efficiency (TLUE). On average, SIT adopters are 21% more land efficient than non-adopters, requiring approximately 24% less land to achieve the same output. Since land is treated as a fixed input in the frontier, the TLUE score directly reflects the effective land needed to produce observed yields. Adoption of improved seed, balanced fertilizer use, and agroecological practices is linked to better resource use, with the largest gains among farmers who initially operate furthest from the frontier. These efficiency improvements may reduce pressure for cropland expansion and support sustainable land management, especially when combined with enabling conditions such as credit access, extension support, and secure tenure. This study provides novel empirical evidence on how productivity improvements through SIT can enhance land use efficiency and contribute to land sparing outcomes. The findings offer insights for policies targeting land degradation neutrality and inclusive agricultural transformation in Ghana and similar contexts.

Abstract

Disease symptoms, sources of inoculum, and patterns of spore release of Mycosphaerella ribis, the cause of Mycosphaerella leaf spot, were studied over three years in an organic blackcurrant planting receiving no fungicide applications. In addition to typical foliar symptoms, also fruit lesions were observed on the cultivars included in the study. Ascospores from leaf litter on the ground were trapped from bud break in April to mid-to-late July, but 99% were released by one month before. Conidia formed in old fruit cluster stalks overwintering on the blackcurrant shrubs were present from bud break to early August, but 99% were trapped from late May to mid-July. Conidia were found in leaf litter but were never captured in the spore trap, and ascospores were observed in old fruit cluster stalks. Degree-day models (base = 0˚C) were used to estimate the proportion of mature spores. Extended periods of dry conditions slowed spore maturation in the field. Models halting degree-day accumulation after 4 or 7 days with no rain (< 0.2 mm) or leaf wetness of < 12 h per day, gave the best performance for release of conidia or ascospores, respectively, if validated by data from controlled conditions in the laboratory. Ascospore release was suppressed during night, and if rain and wetness started during night and continued the following day, very few spores were released before sunrise. The present investigation provides new information that may be used when planning sanitary measures to reduce primary inoculum and predict spore release patterns for Mycosphaerella leaf spot.

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Abstract

The ice-ice disease (IID) impacting the commercially important eucheumatoid seaweed Kappaphycus striatus is characterized by thallus bleaching (whitening), softening, and subsequent disintegration of the affected tissue. The occurrence of IID is thought to be stress-related release of dissolve organic carbon exudates that are utilized as substrate for microbial growth. The presence of pathogenic bacteria can subsequently induce IID manifestations that can jeopardize crop health. In this study, we investigated the role of pathogenic bacteria isolated from diseased green cultivar of K. striatus in inducing IID symptoms in healthy non-axenic brown cultivar of the same species under controlled laboratory conditions. Healthy branches of K. striatus were exposed to four distinct bacterial strains: three isolated from the diseased K . striatus ( Vibrio brasiliensis strain A8, V . brasiliensis strain B2 and V . chemaguriensis strain V1) and a positive control Cytobacillus solani strain-V2. Over a period of ten days, routine administration of each bacterium was conducted during the daily renewal of the filtered seawater medium. The occurrence of symptoms, i.e., typical of IID infection, was observed in samples subjected to additional bacterium but not under the control condition with natural microbiome. Our findings suggest that the presence of pathogenic bacteria, even under non-stressful laboratory conditions, can induce IID disease syndrome with various manifestations, including the development of wounds, abrasions, thallus bleaching, and fragmentation. The samples infected with the positive control C. solani strain-V2 exhibited the most severe bleaching at 80%, followed by V. brasiliensis strain-A8 at 60%, while V. brasiliensis strain-B2 and V, chemaguriensis strain-V1 both induced 50% thallus bleaching.

Abstract

Abstract Background and Aims Efficient phosphorus (P) and management is essential for sustainable arable systems. Cover crops (CCs) are promising, but their performance is uncertain in high-latitudes. This three-year study evaluated CCs’ effects on P dynamics in a P-rich soil undersown in barley in Mid-Norway (63.9°N)—one of the northernmost trials of its kind. Methods A randomized complete block design included three CC treatments: ryegrass (CC1), a ryegrass–clover mix (CC2), and a four species mix including grass, legumes and herbs (CC3), and controls without CC (with/without NPK fertilizer). Soil and plant analyses included total and available P, total N, potentially mineralizable N (PMN), pH, permanganate-oxidizable carbon, root biomass, plant P concentrations, and microbial abundance via qPCR. Statistical analysis was based on Linear Mixed Models (LMMs). Results Cover crops successfully established (average biomass: 1525 kg ha⁻ 1 ), accumulated ~ 7 kg P ha⁻ 1 , and did not reduce barley yields. LMMs showed significant effects of CC treatment on root biomass, total P, and bacteria. Pairwise comparisons also revealed that fungal abundances in CC1 and CC3 were significantly higher than in the unfertilized control. Pairwise regression revealed that soil total P was strongly predicted by root biomass (β = 1.37, P < 0.001). Available P was negatively controlled by microbial pools (Bacteria: β = -9.22, P < 0.001) and residue quality (C:P ratio: β = -0.36, P < 0.001). Conclusions CCs can be used at 63°N without yield penalty. The primary P mechanism is mass-driven sequestration (root biomass) into the stable total P pool. However, P availability is temporally constrained by residue quality and microbial competition. Graphical Abstract