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.
2024
Authors
Sigridur Dalmannsdottir Marit Jørgensen Helga Amdahl Kristoffer Herland Hellton Odd Arne RognliAbstract
Norway stretches from latitude 58° to 71° north. Thus, the climate is very different in the south compared to the north. Since seed production in the north is unpredictable due to the short growing season, commercial seed production of perennial forage grass cultivars has been located in the south-eastern part of Norway. We tested freezing and ice-encasement tolerances of three seed lots of different age of each of the northern-adapted cultivars ‘Engmo’ and ‘Noreng’. The seed lots were prebasic (original), intermediate (mid), and current commercial (late). The results showed that both cultivars had reduced freezing tolerance when comparing plants from the original seed lots with plants from the current commercial seed lots, which originate from several generations of seed multiplication in the south. Regarding tolerance toward ice-encasement, there were no significant differences between seed lots or cultivars. This indicates phenotypic and genetic shifts within the cultivars towards less frost-tolerant populations. It is therefore important to implement seed production regimes of northern-adapted cultivars that reduce the risk of shifts and preserve the cultivar characteristics.
Authors
Akhil Reddy Pashapu Sigridur Dalmannsdottir Marit Jørgensen Odd Arne Rognli Mallikarjuna Rao KoviAbstract
No abstract has been registered
Abstract
The effectiveness of mechanical subsoiling for alleviating subsoil compaction is controversially discussed, particularly due to the sensitivity of mechanically loosened soils towards re-compaction. In order to improve the alleviation potential by subsoiling it was hypothesized that the loss of soil stability by mechanical subsoiling of compacted soils can be reduced by top and subsoil liming. The primary objective was to evaluate whether (a) mechanical subsoiling (to a depth of 35 cm with a subsoiler or a plough with a pan-breaker) could alleviate compaction in a clayey Stagnosol and (b) whether liming could stabilize soil structure to minimize re-compaction. Undisturbed soil samples were collected to assess physical properties in both "compacted", "subsoiled", and "limed", as well as in untreated plots. The Compaction Verification Tool (CVT) identified potentially harmful soil compaction in the subsoil. The results showed that wheeling increased the extent of harmful subsoil compaction (from 8% to 33%) in the first year, which was accompanied with a reduction in crop yields. Subsoiling with a pan-breaker combined with high liming intensity improved soil physical properties and yields and may have mitigated re-compaction in the loosened subsoil. Nevertheless, it is expected to be not economically viable on the studied clay soil.
Abstract
Successful introduction of the new cultivars requires proper pomological, phenological and as well as technological evaluation. It is particularly important at the harsh Norwegian climate conditions. Investigations were conducted with apple cultivar ‘Eden‘ / ‘Wursixo‘ (WUR 6), with the aim to establish an optimal balance between yield, fruit quality and bearing regularity. Four different crop load levels were tested in 3 consecutive years in the orchard planted 3.5 x 1 m and trained as slender spindle. Lower crop load levels guaranteed good return bloom, a very high share of fruits harvested during the first picking, and larger fruits. Increasing crop load led to less intensive return bloom, smaller fruit sizes and higher share of fruits harvested during the second picking. It was found that ‘Eden‘ is strictly alternating cultivar and precise crop load levels according to the tree age and tree vigour were defined. In order to keep ‘Eden‘ trees in regular bearing mode crop load levels should be maintained at 4.5-5 fruits cm-2 of trunk cross-sectional area (TCSA) in the 3rd and 6-7 fruits in the 4th growing season
Abstract
To facilitate nutrient management and the use of manure as a feedstock for biogas production, manure is often separated into a solid and a liquid fraction. The former fraction is usually high in P and low in N, so when incorporated in the soil as fertilizer, it needs to be supplemented by N from, e.g., mineral fertilizers or nitrogen-fixing species. To explore strategies to manage N with solid-separated manure, we examined how the amount of digestate and the N:P ratio of pig digestate, i.e., manure that had partially undergone anaerobic digestion, affected the productivity of Westerwolds ryegrass and red clover in a pot experiment with one soil which was rich and another which was poor in plant nutrients. The soil and plant species treatments were combined with four doses of digestate, which gave plant available phosphorus (P) concentrations of 2, 4, 8, or 16 mg P100 g−1 soil. Ammonium nitrate was dosed to obtain factorial combinations of digestate amount and N:P ratios of 1.8, 4, 8, and 16. Clover was harvested once at the beginning of flowering (15 weeks after seeding), while Westerwolds ryegrass was allowed to regrow three times after being cut at the shooting stage (in total, 4 cuts, 6, 9, 12, and 15 weeks after seeding). Ryegrass yield increased by up to 2.9 times with digestate dosage. Interactions with the N:P ratio and soil type were weak. Hence, the effect of increasing the N:P ratio was additive across digestate dosages. Red clover biomass also increased by up to 39% with digestate dosage. Residual nutrients in the soil after red clover cultivation were affected by the initial differences in soil characteristics but not by digestate treatment or biomass of harvested red clover. A targeted N management is required to benefit from the P-rich digestate in grass cultivation, while the long-term effects of red clover culture on N input need further investigation.
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.
Authors
Narta ElshaniAbstract
No abstract has been registered
Authors
Nicole AndersonAbstract
No abstract has been registered
Authors
Nicole AndersonAbstract
No abstract has been registered
Authors
Nicole AndersonAbstract
No abstract has been registered