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.
2024
Authors
Nicole AndersonAbstract
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Abstract
Strong creeping red fescue (Festuca rubra L. spp. rubra Gaudin) is a cool-season perennial turfgrass widely used in temperate and subalpine regions around the globe. Although creeping red fescue turf is tolerant of shade, low fertility acidic soils, and drought conditions, creeping red fescue seed crops grown in optimal growing environments can lodge, ultimately reducing yield in regions where this important turfgrass is grown for seed. To address this issue, we investigated the effects of two plant growth regulators (PGRs), chlormequat chloride (CCC) and trinexapac-ethyl (TE), on plant height, lodging, and seed yield of strong creeping red fescue over 9 site-years in the Peace River region of western Canada. The study encompassed 6 site-years with first-year stands and 3 site-years with second-year stands. The PGRs were applied alone and in a TE + CCC mixture at the two-node (BBCH 32–33, where BBCH is Biologische Bundesanstalt, Bundessortenamt and Chemische Industrie) and early head emergence (BBCH 51–52) growth stages in first- and second-year stands, respectively. The application of TE, CCC, and their mixture resulted in a differential decrease in lodging and an increase in seed yield in first-year stands. However, PGRs applied at BBCH 51–52 on second-year stands had no effect on seed yield but reduced plant height and lodging. This study found a negative correlation between seed yield and lodging. Among the PGR treatments, the CCC + TE mixture was the most effective in reducing lodging and increasing seed yield of strong creeping red fescue.
Abstract
Orchardgrass (Dactylis glomerata L.) is an important forage seed crop, but unlike other cool-season grasses, seed yields have not increased over time. Seed yield increases in orchardgrass may be possible with plant growth regulators (PGRs) such as trinexapac-ethyl (TE) and chlormequat chloride (CCC). Field trials were conducted at Hyslop Experimental Farm near Corvallis, Oregon, over three crop years (2017–2019) to examine the effects of spring nitrogen (N) and PGRs on seed production characteristics in orchardgrass. Spring N treatments included 0, 112, 157, and 202 kg N ha−1 and PGR applications were timed using the BBCH (Biologische Bundesanstalt, Bundessortenamt und Chemische Industrie) scale. Four PGR treatments included an untreated control, 210 g TE ha−1 at BBCH 32, 210 g TE ha−1 at BBCH 51, and 105 g TE ha−1 + 1500 g CCC ha−1 at BBCH 32. An interaction of spring N and PGR increased seed yields in 2 years, while spring N and PGR increased seed yield independently in the other year. The combination of TE and CCC PGRs did not increase seed yield over TE alone. Seed yield increases from spring N were due to an increase in seed number m−2, while increases in seed yield attributable to PGRs were the result of increased seed number m−2 and harvest index. This study suggests that the combination of 112 kg ha−1 spring N and 210 g ha−1 TE PGR is the best practice to maximize seed yield in orchardgrass.
Abstract
Aims To develop a methodology to study uptake and redistribution by plants of NH4+ from deep soil, applying it to investigate deep root N uptake by cultivated grassland species. Methods A slow-release 15NH4+ label adsorbed to clinoptilolite was placed into soil (depth 42 cm) well below the densest root zone in well-established monospecific stands of five grass and two clover species. Species showing a variety of deep rooting patterns, N acquisition strategy, forage qualities, and persistence in hemiboreal conditions were chosen. The label was placed in early spring and tracked throughout one or two growing seasons in two repeated experiments. Results After two growing seasons ~ 90% of the label was tracked in the soil and harvested herbage of grasses, less in clovers. Deep N uptake was limited in spring, increased during mid-season, and was strongest in autumn in all species, despite lower herbage yield in autumn. Species differed in ability to recover and maintain 15N in the soil–plant system. In one growing season, Lolium perenne L., Phleum pratense L., Schedonorus pratensis (Huds.) P.Beauv. and Schedonorus arundinaceus (Schreb.) Dumort herbage recovered ~ 65% of the label, Poa pratensis L. 54%, and Trifolium pratense L. and Trifolium repens L. 36–48%. Label transport to topsoil was observed, mainly attributable to plant nutrient redistribution rather than physical diffusion. Conclusions The innovative slow-release 15N label enabled tracing species differences and seasonal changes in uptake of NH4+ from deep soil. Among the tall-growing grasses, growth vigor appeared as important for deep N uptake as expected root depth.
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Abstract
Background The Norwegian sheep farming system relies on forages, such as grass silage during winter and grazing cultivated leys and rangeland pastures during summer. Sheep and other ruminants produce enteric methane (CH4), a greenhouse gas of interest, and there is a need for reliable data on gas emissions from sheep capturing both the indoor feeding period and the grazing season. This study utilized an in vitro gas technique (with standard cow rumen fluid) and modeling approach to estimate CH4 production and fermentation patterns based on two different qualities of Italian ryegrass (Lolium multiflorum) pasture under sheep grazing. Results Herbage quality was examined for two 10-day periods, in July and August. Differences in chemical composition of the herbage during these periods had an impact on herbage digestibility and CH4 production. Total gas production and CH4 levels were significantly higher for lower quality herbage grazed in July than for higher quality herbage grazed in August (p < 0.005). Production of volatile fatty acids in the rumen remained constant between the two periods, but the higher acetate to propionate (A/P) ratio correlated with the higher CH4 production. Conclusion These findings suggest that pasture quality is an important factor to consider when implementing grazing strategies to reduce enteric CH4 production in sheep.
Abstract
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