Anne-Grete Roer Hjelkrem
Research Scientist
Attachments
CV (januar 2025)Biography
PhD from NMBU with a focus on uncertainty in mathematical models (2010) followed by a PostDoc at NTNU in life cycle analysis (LCA).
My research topics include:
- Development of warning models for decision support in fungal diseases, toxins, pests and weeds
- Development of the NORNE model for prdiction of yield and quality in forage
- Development of a modeling platform for calculating greenhouse gas emissions in agriculture in line with the national emissions account
- Development of a modeling platform for calculating reference pathways and action scenarios
- Environmental analyses (LCA) in food production
Abstract
No abstract has been registered
Abstract
Beitebruk er viktig for ressursutnyttelse, selvforsyning, dyrevelferd og kulturlandskap, og det er et politisk mål å øke beiting. Klimaeffektene av beiting har imidlertid vært lite vektlagt. Rapporten sammenstiller kunnskap om hvordan beitedyr påvirker klima gjennom både klimagassutslipp og endringer i vegetasjon og areal. Effektene varierer betydelig mellom arealtyper, beitetrykk, dyreslag og lokale forhold, noe som gjør det vanskelig å trekke generelle konklusjoner. I klimagassregnskapet er beiting særlig relevant for arealbruksendringer, som avskoging til beite og utslipp fra tidligere drenert myr. Effekter på enterisk metan og utslipp fra husdyrgjødsel er relativt små, selv om enkelte norske studier antyder noe lavere metanutslipp ved godt beite på fulldyrka jord. Biogeofysiske effekter som albedo er lite kartlagt, men kan ha nedkjølende effekt i noen områder. Rapporten peker på to hovedutfordringer: behov for sterkere insentiver til å bruke eksisterende innmarksbeiter fremfor nyrydding, og potensial for mer beiting av melkekyr på fulldyrka jord. Det trengs mer forskning for å bedre beregne effekter av beiting i klimagassregnskapet, særlig knyttet til enterisk metan, jordkarbon og beitetrykk i utmark.
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.
