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.
2007
Abstract
No abstract has been registered
Authors
Mehreteab TesfaiAbstract
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Abstract
Podzol development was investigated in a chronosequence on sandy beach sediments, the ages of the soils ranging from 2,400 to 8,500 years. All soil properties investigated-the organic matter content of the B horizons, clay content, Fe-o, Al-o, Si-o, Fe-o/Fe-d and Fe-d/Fe-t - tend to increase with advancing podzolization, and are strongly correlated with soil age. Topsoil pH values decrease with age. The characteristic Bh and Bs horizons had developed after approximately 4,000 years.
Authors
Svein Ole Borgen Guro Ådnegard SkarstadAbstract
No abstract has been registered
Authors
Stig Strandli GezeliusAbstract
No abstract has been registered
Authors
Clive Kaiser Lars Sekse Mekjell Meland Lynn E. LongAbstract
No abstract has been registered
Authors
Mekjell Meland Magne MoeAbstract
The performance of the plum rootstocks Marianna, Pixy and Wangenheim using St. Julien A as a standard to the cultivars `Avalon", `Edda", `Excalibur", `Jubileum", `Reeves" and `Victoria" was assessed in a field trial in western Norway at 60" North. Trees were planted in spring 1999, the plant material was one-year-old whips, spaced 2.0 x 4.5 m and formed with a central leader as free spindles. Soil management was grass in the alleyways and herbicide strips 1-m wide along the tree rows. Tree vigour, yield, fruit size and yield efficentcy were evaluated for the six subsequent years. Tree size was significantly affected by the rootstocks after six years growth. Wangenheim produced the smallest and St. Julien A and Pixy the largest trees as measured by trunk cross-sectional area in average for the different cultivars. St. Julien A and Pixy were the most productive rootstocks for the cultivars. However, Pixy produced significant larger yields per tree to the cultivar `Reeves" than St. Julien A. Trees on Pixy were the most yield efficient for all cultivars with the exception of `Victoria". The fruit sizes were in general large for all cultivars and became little affected by the different rootstocks. Fruit quality characterized by the content of soluble solids was in general high and did not differ between trees on the various rootstocks. The cultivar `Avalon" had the highest contents of soluble solids.
Authors
Mekjell MelandAbstract
During the period 1998-2000, thinning trials were conducted using bloom thinners on mature European plum trees at Ullensvang and at fruit growers sites in western Norway. In 1998, unsprayed control and handthinned `Victoria" trees were compared with trees treated at full bloom with a single application of 1% Armothin® or 1.5% ammoniumthiosulphate (ATS). The same program was conducted in the following two years with the addition of a single full bloom treatment with 250 ppm ethephon and a post-bloom application one month after full bloom with the mixture 10 ppm 1-napththaleneacetic acid (NAA) and 75 ppm ethephon. High volume sprays were conducted the first two years and low volume the last year. Thinning trials testing 1-1.5 % ATS and 5-7 % lime sulphur in comparison with unthinned and handthinned trees to the cultivars `Opal" and `Victoria" were conducted in 2000, at growers sites. Generally, thinning treatments reduced crop load and enhanced fruit quality (fruit size, soluble solid content, fruit firmness and ground and surface colour), but the results varied from year to year. Fruit set was reduced to about half of control values and the percentage of class 1 fruits was doubled compared to the control trees. High volume sprays to running off was more effective than low volume. The cultivar `Opal" was more sensitive to ATS than `Victoria" and a low dosage recommended. All thinning compounds caused some minor leaf injury but no fruit damage. The flower thinners were efficient at rather low temperture. No differences in the amount of gummosis (internal disorder of the fruits) were observed due to treatments on the `Victoria" plums. Return bloom was improved by thinning. In conclusion, a single dilute application at full bloom of 1% Armothin®, 1.5% ATS or 250 ppm ethephon or one application of the mixture 10 ppm NAA-75 ppm ethephon four weeks after bloom reduced fruit set and crop load and increased the fruit quality and return bloom to the cultivar `Victoria". Similar results gave one dilute spray with 1 % ATS or 5 % lime sulphur at full bloom to the cultivar `Opal".
Abstract
Histological properties of the graft union between a rootstock and scion may provide a mechanistic explanation why dwarfing rootstocks are able to reduce the growth of the tree. In order to investigate the relationship between growth and the amount of functional xylem tissue of potted sweet cherry trees, an experiment was conducted during 2002-2003. One year old field budded and bench grafted (from greenhouse) sweet cherry trees of the cultivars Van, Ulster and Lapins in all combinations of the three rootstocks Prunus avium seedling, Colt and Gisela 5 were grown in pots for two growing seasons. After shoot extension had terminated when trees were in full leaf the second year, the total growth of the different parts of the trees and the functional area using safranin staining were measured. The total mass production (tree dry weight, the length of two year old wood and number of leaves) was significantly larger in the budded trees. Similarly the trunk cross sectional area was significantly larger 10 cm above and in the middle of the graft union, but not 10 cm below it. The Colt trees were the most vigorous followed by the seedling and Gisela 5. Minor differences between the different cultivars were registered. Xylem staining with aqueous safranin combined with quantitative image analysis showed that the rootstock stem had a higher proportion of stained tissue than the scion stem. Sections taken in the middle of the graft tissue and 10 cm above showed that the proportion of stained tissue declined proportionally with the distance from the roots. The total area of stained stem xylem was larger for the two vigorous rootstocks compared to Gisela 5. Small differences were observed between cultivars and propagation methods.
Abstract
Combinations of covering and fungicide applications were tested on two sweet cherry cultivars; Van during two years (2001 and 2002) and Lapins three years (2001"2003). The following treatments were tested in 2001 and 2002: (i) covering during flowering and from 5 to 6 weeks prior to harvest and throughout harvest, no fungicides applied, (ii) as (i) but fungicides were applied once or twice between the two covering periods, (iii) covered 5 to 6 weeks prior to harvest and throughout harvest, fungicides applied two or three times prior to covering, and (iv) uncovered throughout the season, fungicides applied two or three times in the period from flowering towards harvest. In 2003, the trees were covered only from 5 to 6 weeks prior to harvest and throughout harvest. Both treatments that year received fungicide applications during flowering, but one of the treatments was left unsprayed during the green fruit period prior to covering. Every combination of covering and fungicide applications reduced total fruit decay at harvest significantly compared to a full fungicide programme and no covering. In three of four trials when the trees were covered during flowering and prior to harvest, and fungicide applications were omitted in the green fruit phase between the covering periods, no significant increase in fruit rot occurred compared to treatments where fungicides were applied. However, in one trial there was a significant increase in fruit rot by leaving out one fungicide spray during that intermittent period. Furthermore, if fungicides were only applied during flowering and not on green fruit before covering in 2003, a significant increase in fruit rot occurred. Thus, leaving out fungicide applications during that supposedly less susceptible green fruit period, increased the risk of acquiring fruit rot. Applying fungicides during the green fruit stage significantly reduced the amount of brown rot in four of five trials and anthracnose in one of five trials. No negative effect on fruit quality was found from the extended covering periods. It can be concluded that covering effectively replaced fungicide applications during flowering and prior to harvest.