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.
2006
Forfattere
Roald AasenSammendrag
In the Nordic countries several composting plants for source separated organic household waste (SSOW) have experiences problems with establishment of high-rate respiration processes. The problems with start-up of the high-rate composting phase can be related to sensitivity of the thermophilic microflora to low pH in the composting material. Low pH is caused by high content of organic acids produced by fermenting microorganisms in the waste. In our studies we investigated the effect of different ratio of SSOW mixed with bulking agent in the development of short organic acid content and the shift from a fermentative to aerobic bacteria population during composting.
Forfattere
Grete Waaseth Roar Moe Royal D. Heins Svein GrimstadSammendrag
Varying photo thermal ratios (PTR) were supplied to Salvia x superba Stapf "Blaukönigin" during pre-inductive vegetative development with the exception of a short germination period under uniform conditions. In addition, both unvernalized plants and plants receiving a saturating vernalization treatment of 6 weeks at 5 oC were given two photosynthetic photon flux (PPF) levels (50 or 200 µmol m-2 s-1) during subsequent inductive 16-hour long days. There were no effects of PTR treatments during vegetative development on subsequent flowering. However, the higher PPF level during inductive long days significantly accelerated floral evocation in unvernalized plants, lowering the leaf number at flowering. The effect was practically negligent after the vernalization requirement was saturated. In a second experiment, varying periods (4, 7, 10, and 14 days or until anthesis) at a PPF of 200 µmol m-2 s-1 during 20-hour days were given at the beginning of a long day treatment, either with or without preceding vernalization treatment. Flowering percentage increased considerably as the period at 200 µmol m-2 s-1 was extended compared with plants grown at a lower PPF of 50 µmol m-2 s-1. However, the leaf number on flowering plants was not affected, except in unvernalized plants receiving the highest PPF continuously until anthesis, where leaf number was reduced by almost 50%. We propose that the PPF dependent flowering is facilitated either by the rate of ongoing assimilation or rapid mobilization of stored carbohydrates at the time of evocation. Abortion of floral primordia under the lower PPF (50 µmol m-2 s-1) irrespective of vernalization treatment indicates that the assimilate requirement for flower bud development is independent of the mechanism for floral evocation.
Forfattere
Gunn Mari StrømengSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Liv Sognnes Gustav Fystro Samson Øpstad Arve Arstein Trond BørresenSammendrag
In terms of agricultural use, peat soils have weak structure, high water content, insufficient soil aeration and poor thermal properties resulting in suboptimal physical properties and yields of grass. During the period 1978 - 1995, a long-term field trial was conducted on highly decomposed peat soil in order to investigate the impact of adding mineral materials to improve soil characteristics and increase grass yield. Shell sand or moraine soil (200, 400 or 800 m(3) ha(-1)) was incorporated into peat soil. Generally, addition of both shell sand and moraine soil improved the physical properties of the soil and grass production. During the first nine years, shell sand ( 400 m 3 ha(-1)) was the most efficient. Thereafter, moraine soil ( 400 and 800 m(3) ha(-1)) seemed most beneficial. This study indicates that additions of shell sand or moraine soil to peat are appropriate methods to improve and conserve the physical properties and cropping potential of these vulnerable soils.
Forfattere
Lars Nesheim Gustav FystroSammendrag
The resources of rock phosphates are limited. Common use as P fertiliser has to be considered, both in environmental and economical perspectives. Applied superphosphate in many former plant nutrient investigations ruled out the possibility of consistent discussions of the separate S and P effects. The objective of the presented field experiments was to test how plant growth in grassland relates to proposed critical values of herbage P to N relationships. Three field trials were established on soils low in P. Five levels of P fertilisation (0, 5, 10, 20 and 50 kg P ha-1 yr-1) and two levels of N (normal and 50 % of normal) were applied. The trials were harvested in two subsequent years. Plant P uptake on unfertilised plots was higher then expected, and uptake of applied P was lower. Thus, the relation between relative dry matter yield and P/N in plants was not as detailed examined as planned, however, the yield decrease following low P/N was in accordance to our hypothesis. When 20 kg P ha-1 was applied only 14 % was found in the harvested material.
Sammendrag
Total anti-oxidant capacity (TAC) and the contents of mono- and disaccharides, and organic acids were determined in strawberry fruit from ten genotypes sampled from eight experimental sites in Norway in 2002 and 2003.The difference between genotypes was significant for all recorded traits, and it appeared possible to select for all traits in breeding programmes. On average, the Norwegian bred cultivar `Carmen" had a TAC of 30.07 mmol kg"1 fresh weight (FW), compared to 23.16 mmol kg"1 FW in the standard cultivar `Korona". TAC was negatively correlated with fruit size, rainfall and leaf surface humidity, but was positively correlated with the minimum temperature on the day prior to sampling. Mono- and di-saccharide contents were negatively correlated with both minimum and maximum temperatures, and with wind velocity. It was confirmed that the sugars:organic acids ratio was inversely related to the maximum temperature on the day before harvest, which supports anecdotal claims that strawberries grown in northern areas have, on average, better flavour.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Ingvald Røsberg Jon Frank Arne O. StuanesSammendrag
Soil uptake of N, P, and K from the unfertilized plots leads to a depletion of these elements, but also very little leaching. Upon addition of N, P, K, Mg, Ca, and S, soil uptake and nutrient accumulation in the soil usually increased at the same time. The high doses of N, P, K, and S in the "optimal" treatment gave a distinct response with higher uptake from the soil and higher accumulation in the soil. No P was leached from the soil, while about one fourth to one third of the applied N, K, and Mg were leached. The treatment induced an unacceptably high nitrate leaching, and must therefore be regarded as "suboptimal". (c) 2006 Elsevier B.V All rights reserved. Tree growth and nutrient cycling of N, P, K, Mg, Ca, S, and B were examined after four growing seasons in a pine ecosystem in southern Norway. The Scots pine (Pinus sylvestris L.) stand, growing on a Cambic Arenosol, was 33 years old and had a medium site index class. The randomized block experiment had six treatments and three replicates: (1) control, (2) 3000 kg per hectare lime, (3) 3000 kg per hectare dolomite, (4) 3000 kg per hectare dolomite and (5) 6000 kg per hectare dolomite, both treatments (4 and 5) with the fertilizers KCl and superphosphate, and (6) 3000 kg per hectare dolomite with KCl, superphosphate, NH4NO3, kieserite, and borax, and denoted as "optimal" treatment. The "optimal" treatment gave a significantly higher annual increase in tree height and diameter, stand basal area and volume than the control and lime treatments. The dry mass of needles and branches increased slightly for the treatments nos. 3-5 compared to the control and lime treatments, with the most distinct increase for the "optimal" treatment. Highest dry mass of stem wood + bark was found for the treatments nos. 3-6. The nutrient contents in needles were highest for the "optimal" treatment, while dolomite without fertilizer elevated the Mg content in both needles and branches. The nutrient concentrations in the current year's needles increased the most for the "optimal" treatment, except for Ca and Mg. The addition of lime gave the highest concentration of Ca in needles compared to the other treatments. The amounts of N, P, S, and B in the forest floor were also highest for the "optimal" treatment. Soil uptake of N, P, and K from the unfertilized plots leads to a depletion of these elements, but also very little leaching. Upon addition of N, P, K, Mg, Ca, and S, soil uptake and nutrient accumulation in the soil usually increased at the same time. The high doses of N, P, K, and S in the "optimal" treatment gave a distinct response with higher uptake from the soil and higher accumulation in the soil. No P was leached from the soil, while about one fourth to one third of the applied N, K, and Mg were leached. The treatment induced an unacceptably high nitrate leaching, and must therefore be regarded as "suboptimal".
Sammendrag
A commercial extract of neem (NeemAzal-T) and a simple extract of pulverised seeds extracted in warm water were tested against the cabbage pest Mamestra brassicae L. Oviposition was reduced to half the number of eggs per plant by the neem treatment. The number of eggs that hatched was not affected by the neem treatment, but development of these larvae was strongly inhibited and all larvae in the neem treatment died within two weeks without reaching 2nd instar. The concentration of the active ingredient azadirachtin-A (the azadirachtin component in NeemAzal-T) needed to protect plants from damage by 2nd instar larvae was 8 "g ml"1. The lethal doses for 2nd instar larvae were 6.2 and 17.2 "g ml"1 for LC50 and LC95, respectively. NeemAzal-T protected plants from damage for at least three weeks if applied before oviposition, or at least two weeks if applied against 2nd instar larvae. In these studies, neem inhibited oviposition, larval development and feeding, and greatly increased mortality.