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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.

2016

Sammendrag

A future wetter climate in Northern Europe may increase soil compaction from traffic of heavy machinery. This study investigated the impact of tractor traffic on grassland yield, soil physical properties and penetration resistance in three experimental field trials in Norway; on medium sand at Tjøtta, Nordland, on silty medium sand at Fureneset, Sogn og Fjordane and on silt at Løken, Oppland. The experiments were conducted in a split-plot design with three levels of two wheel-by-wheel passes with tractor traffic after each cut: no traffic, light tractor or heavy tractor on large plots, and three different seed mixtures on small plots. The yield reduction by tractor traffic was 26% at Løken, 4% at Fureneset and 1% at Tjøtta. There was a positive correlation between soil moisture content and yield reduction by traffic. Tractor traffic reduced pore volume and air capacity and increased bulk density, compaction degree and penetration resistance with the largest effect at Løken and the smallest at Tjøtta. There were no statistically significant differences in yield or soil physical properties between light and heavy tractor. The study shows that soil texture and soil moisture content are major factors explaining traffic effects on soil physical properties and grassland yield.

Sammendrag

Large areas of cultivated grassland are annually abandoned and no longer used for production in Norway. Such areas will over time be encroached by shrubs and trees, which is regarded as undesirable. We assessed plant community development, pasture production, herbage quality and pasture utilization by sheep and heifers of a grassland that has been unmanaged for 12 years. e experiment was run for two consecutive years. Sheep grazed the whole area for one month in spring and autumn. During the summer, the area was assigned to three replicated treatments: (1) control with no management; (2) grazing heifers; and (3) grazing sheep with off€spring. The stocking rate was 1.8 LU ha-1, in both b and c, for a duration of one month. The area was left resting for a month aer treatment and before autumn sheep grazing. Pasture production and herbage intake was estimated using grazing exclosure cages. Herbage consumed during summer period was on average 211 g DM m-2 and the pasture utilization was 55%. The annual consumption and utilization was 336 g DM m-2 and 62% in the grazed treatments and 28 g DM m-2 and 15% in the control, respectively. Total annual pasture production was on average 72% higher in the grazed treatments compared to the control. Tere was no diff€erence between the grazed treatments on annual production, herbage intake or pasture utilization. Grazing stimulated herbage production, and such abandoned grasslands are valuable forage resources.

Sammendrag

Large areas of cultivated grassland are annually abandoned and no longer used for production in Norway. Such areas will over time be encroached by shrubs and trees, which is regarded as undesirable. We assessed plant community development, pasture production, herbage quality and pasture utilization by sheep and heifers of a grassland that has been unmanaged for 12 years. e experiment was run for two consecutive years. Sheep grazed the whole area for one month in spring and autumn. During the summer, the area was assigned to three replicated treatments: (1) control with no management; (2) grazing heifers; and (3) grazing sheep with off€spring. The stocking rate was 1.8 LU ha-1, in both b and c, for a duration of one month. The area was left resting for a month aer treatment and before autumn sheep grazing. Pasture production and herbage intake was estimated using grazing exclosure cages. Herbage consumed during summer period was on average 211 g DM m-2 and the pasture utilization was 55%. The annual consumption and utilization was 336 g DM m-2 and 62% in the grazed treatments and 28 g DM m-2 and 15% in the control, respectively. Total annual pasture production was on average 72% higher in the grazed treatments compared to the control. Tere was no diff€erence between the grazed treatments on annual production, herbage intake or pasture utilization. Grazing stimulated herbage production, and such abandoned grasslands are valuable forage resources.