| 1. |
- Jönsson Belyazid, Ulrika, et al.
(författare)
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A comparative study of two methods for determination of pH, exchangeable base cations, and aluminum
- 2002
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Ingår i: Communications in Soil Science and Plant Analysis. - 0010-3624. ; 33:19-20, s. 3809-3824
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Tidskriftsartikel (refereegranskat)abstract
- The ability to compare soil chemical data achieved by different chemical extraction methods is a necessity for an efficient long-term monitoring of soils and for comparisons of results from regional soil surveys with differing standard methods. This study compares two common, methods for analysis of soil chemical properties, the combination of soil extraction in 1.0 M NH4Cl and 1.0 M KCl and the single extraction method using 0.1 M BaCl2. Results show that the two methods do not differ in extraction capability with regard to pH and exchangeable calcium (Ca) and magnesium (Mg). However, there is less agreement in extraction capability with regard. to potassium (K), sodium (Na), and aluminum (Al). For these elements, BaCl2 is less efficient than NH4Cl and KCl. Despite the differences in extraction capability between BaCl2 and KCl/NH4Cl, regression analyses showed that the methods are well correlated (high regression coefficients for all, elements). Thus, transformation of data achieved by one method to estimated values of the other method are possible. Results from this study may be an important tool for comparisons of mineral soil data achieved by the two methods.
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| 2. |
- Jönsson Belyazid, Ulrika, et al.
(författare)
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Acidification-induced chemical changes in coniferous forest soils in southern Sweden 1988-1999
- 2003
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Ingår i: Environmental Pollution. - 0269-7491. ; 123:1, s. 75-83
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Tidskriftsartikel (refereegranskat)abstract
- Thirty-two Norway spruce [Picea abies (L.) Karst.] and Scots pine (Pinus sylvestris L.) stands in southern Sweden were studied for a period of 12 years to evaluate acidification-induced chemical changes in the soil. Soil, at 20-30 cm depth in the mineral layer, was sampled three times during this period (1988, 1993 and 1999). The results show that pH(BaCl2) in mineral soil decreased by, on average, 0.17 units between 1988 and 1999, accompanied by an increase in aluminium (Al) concentration and a decrease in base saturation in the soil. In 1999, the base saturation was below 5% in 58% of the 32 sites compared with 16% in 1988 and 7% in 1993. Concentrations of calcium (Ca), potassium (K) and magnesium (Mg) are low and decreasing. Based on C/N ratios in humus, 45% of the sites may be subjected to leaching of considerable amounts of nitrate. The results show that the acidification of coniferous forest soils in southern Sweden is continuing, and that the negative effects on the nutrient status in soil are extensive. The results are compared with reference values for productive, long-term sustainably managed boreal coniferous or mixed forest soils and implications for long-term sustainability are discussed.
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| 3. |
- Jönsson Belyazid, Ulrika, et al.
(författare)
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Pathogenicity of Swedish isolates of Phytophthora quercina to Quercus robur in two different soils
- 2003
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Ingår i: New Phytologist. - : Wiley. - 1469-8137 .- 0028-646X. ; 158:2, s. 355-364
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Tidskriftsartikel (refereegranskat)abstract
- Several studies have demonstrated the involvement of soil-borne Phytophthora species, especially Phytophthora quercina , in European oak decline. However, knowledge about the pathogenicity of P. quercina in natural forest soils is limited. The short-term effects of two south-Swedish isolates of P. quercina on root vitality of Quercus robur seedlings grown in two different soils, one high pH, nutrient-rich peat-sand mixture and one acid, nitrogen-rich but otherwise nutrient-poor forest soil are described. Pathogenicity of P. quercina was tested using a soil infestation method under a restricted mesic water regime without prolonged flooding of the seedlings. There was a significant difference in dead fine-root length between control seedlings and seedlings grown in soil infested with P. quercina . Trends were similar for both soil types and isolates, but there was a higher percentage of fine-root die-back and more severe damage on coarse roots in the acid forest soil. No effects on above-ground growth or leaf nutrient concentration between control seedlings and infected seedlings were found. The results confirm the pathogenicity of south-Swedish isolates of P. quercina in acid forest soils under restricted water availability. Stress-induced susceptibility of the seedlings and/or increased aggressiveness of the pathogen in the forest soil are discussed as key factors to explain the difference in root die-back between soil types.
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| 4. |
- Göransson, Hans, et al.
(författare)
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Effects on soil chemistry and nutrient uptake by admixture of birch in Norway spruce stands
- 2002
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Ingår i: Reports in Ecology and Environmental Engineering. - 1104-2877. ; 1, s. 86-97
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Konferensbidrag (refereegranskat)abstract
- spruce stands, pure Norway spruce, pure birch and mixed plots of birch and Norway spruce were established in 1984/1985 at four locations in southern and central Sweden. The soil was sampled down to 30cm soil depth in1984 /1986, 1993 and 2001. We report results on soil chemical changes and changes in base cation stores above and below ground. No significant positive effect on soil chemical status of the birch admixture was found even though the uptake of base cations into the trees was smaller in the mixed stands. All treatments showed a decrease in soil chemical status in the mineral soil over time.
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| 5. |
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| 6. |
- Jönsson, Anna Maria, et al.
(författare)
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Excess nitrogen affects the frost sensitivity of the inner bark of Norway spruce
- 2004
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Ingår i: Annals of Forest Science. - : EDP Sciences. - 1286-4560 .- 1297-966X. ; 61:4, s. 293-298
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Tidskriftsartikel (refereegranskat)abstract
- The sensitivity to frost in the living inner bark of trees have been hypothesised to be influenced by acid rain and N deposition through changes in nutrient balance and carbon metabolism. At the Skogaby experimental site, situated in southern Sweden, Norway spruce in control plots, plots fertilized with ammonium sulphate and plots fertilized with mineral nutrients except N were compared in this respect. Frost sensitivity was measured by electrolytic leakage and expressed as an index of injury. The results showed increased sensitivity to frost in the bark of trees treated with continuous applications of ammonium sulphate for 11 years. This was probably not only a direct effect of high nitrogen availability, but also caused by insufficient levels of other nutrients due to the rapid growth and changes in soil chemistry induced by the addition of ammonium sulphate. Mainly Mg and K seemed to be of importance for retaining a good frost resistance, supporting the hypothesis that nutrient imbalances increases the risk for development of frost related bark lesions in southern Sweden.
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| 7. |
- Rosengren, Ulrika, et al.
(författare)
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Increasing the sensitivity of the N-15 root bioassay technique: Suggested procedures
- 2003
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Ingår i: Communications in Soil Science and Plant Analysis. - 0010-3624. ; 34:15-16, s. 2363-2373
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Tidskriftsartikel (refereegranskat)abstract
- The diagnosis of tree nutrient demand for nitrogen (N), phosphorus (P), and potassium (K) is possible using a root bioassay with excised roots, to measure the rate of uptake of the corresponding isotope. In this study, Norway spruce (Picea abies) roots were used to test the uptake response in roots of different diameter. The 15 N bioassay has been developed to test for nitrogen demand by plants, where high 15 N uptake demonstrates nitrogen limitation. Sometimes sample variability may mask potential treatment differences, but we have shown that when the fine root fraction of <1 mm diameter is selected rather than the whole root, the sensitivity can be significantly increased. Roots of different diameters revealed a 2-50 fold difference in the response to the N bioassay. If samples are restricted to the fine roots, the method is also more comparable to the bioassays for P and K.
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| 8. |
- Rosengren, Ulrika, et al.
(författare)
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Nitrogen and nutrient imbalance
- 2002
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Ingår i: Developing principles and models for sustainable forestry in Sweden. - 1402009992
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Abstract is not available
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| 9. |
- Sheppard, L J, et al.
(författare)
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Do nitrogen additions change the sensitivity of detached shoots from Sitka and Norway spruce to freezing temperatures? Evidence from three field manipulation studies
- 2003
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 18:6, s. 487-498
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Tidskriftsartikel (refereegranskat)abstract
- Controversy surrounds the impact of atmospheric nitrogen (N) deposition on frost hardiness. There are no specific field studies and the relevance of data from N fertilizer studies is questionable. Field N manipulation experiments with Norway spruce [Picea abies . (L) Karst.] at Skogaby, Sweden, and Sitka spruce [P. sitchensis . (Bong.) Carr.] at Aber in Wales and Deepsyke in Scotland were sampled in November/December to assess hardiness. The N was supplied with different accompanying ions, from 35 to 100 kg N ha(-1) yr(-1), as solid fertilizer, in irrigation water or to the canopy. Detached shoots were experimentally frozen and damage was assessed from electrolyte leakage. Frost hardiness was not significantly affected by the N treatments irrespective of site, dose, species or length of treatment. Shoots that had received N were generally the most hardy. The results are consistent with the nutritional status of the foliage at the time of sampling.
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| 10. |
- Stjernquist, Ingrid, et al.
(författare)
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Forest health indicators.
- 2002
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Ingår i: Developing principles and models for sustainable forestry in Sweden. - 1402009992
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Abstract is not available
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