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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.

2020

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Sammendrag

* In forests, ectomycorrhizal mycelium is pivotal for driving soil carbon and nutrient cycles, but how ectomycorrhizal mycelial dynamics vary in ecosystems with drought periods is unknown. We quantified the production and turnover of mycorrhizal mycelium in Mediterranean Pinus pinaster, Pinus sylvestris and Quercus ilex forests and related the estimates to standardised precipitation index (SPI), to study how mycelial dynamics relates to tree species and drought‐moisture conditions. * Production and turnover of mycelium was estimated between July and February, by quantifying the fungal biomass (ergosterol) in ingrowth mesh bags and using statistical modelling. SPI for time scales of 1–3 months was calculated from precipitation records and precipitation data over the study period. * Forests dominated by Pinus trees displayed higher biomass but were seasonally more variable, as opposed to Q. ilex forests where the mycelial biomass remained lower and stable over the season. Production and turnover, respectively, varied between 1.4–5.9 kg ha−1 d−1 and 7.2–9.9 times yr−1 over the different forest types and were positively correlated with 2‐month and 3‐month SPI over the study period. * Our results demonstrated that mycorrhizal mycelial biomass varied with season and tree species and we speculate that production and turnover are related to physiology and plant host performance during drought.

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By 2050, global food consumption is expected to rise by 60% compared to the 2005–2007 level. In sub-Saharan Africa (SSA), the population increase may be as much as 250% by the same period. Hence, there is an urgent need to increase food production and introduce productivity-enhancing measures in SSA agriculture, including the livestock sector, which is the main focus of this article. The current productivity of the Tanzanian livestock sector is low due to seasonal variations in the availability and quality of pasture and other feeds. The cattle gain weight during the rainy season and lose weight in the subsequent dry season. Additionally, pastoralists face challenges due to the conversion of grazing areas into cropland, overgrazing, and the increasingly frequent droughts. Although the optimum age for slaughter is 3.5–4.5 years, farmers in Tanzania slaughter their cows at 5–6 years. This article argues that this may be an unhelpful economical management practice. To study the effects of improved feeding on economic performance, we collected data on on-farm supplementation experiments with indigenous Zebu cattle, in collaboration with pastoral communities and a large-scale commercial wheat farm in Hanang, Tanzania. The study compared the income and costs associated with traditional cattle keeping (TS) for 6 years at slaughter, with that of two levels of concentrate supplementation, low (LSS) and medium (MSS), allowing for slaughtering at 4.5 and 3.5 years, respectively. Adjusted net margins for the three systems were 199, 911 and 978 USD, respectively. Our results strongly suggest that farmers should supplement the feeding of their young stock regularly, in times when the animals cannot sustain themselves on grazing alone. The primary explanations for the recommendation were that supplementation would lead to increased production of meat and reduced variable costs, that is, feeds and drugs. Our study was limited to steers. Future studies should include supplementation of cows to obtain annual calving and use of crop by-products instead of concentrates.

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Norge, terrestrisk naturovervåking, dokumentasjon, områder, metoder, data, skog, fjell, vegetasjon, epifytter, bjørkemålere, smågnagere, fugler, Norway, terrestrial ecosystem monitoring, documentation, sites, methods, data, forest, mountains, vegetation, epiphytes, birch defoliating moths, small rodents, birds