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Sveriges lantbruksuniversitet Klas Rosén Department of Soil and Environment SLU – Uppsala Sweden

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Presentation on theme: "Sveriges lantbruksuniversitet Klas Rosén Department of Soil and Environment SLU – Uppsala Sweden"— Presentation transcript:

1 Sveriges lantbruksuniversitet Klas Rosén Department of Soil and Environment SLU – Uppsala Sweden Long-term effect of single potas- sium fertilization on 137 Cs levels in plants and fungi in a boreal forest in Sweden K. Rosén, M. Vinichuk I. Nikolova K-J. Johanson

2 Sveriges lantbruksuniversitet Radioecology activities at SLU Agricultural ecosystems -important food chains, long-term transfer of Cs -countermeasures Forest ecosystems -nutrient-poor systems, long-term transfer of Cs -mushrooms, moose, deer, wild boar, fish Natural Radionuclides - in soil - water - plant - animal – systems - in agricultural and mining areas Reindeer Dynamic models Monitoring – experiments - modelling Radiation protection & national preparedness (in case of nuclear accidents)

3 Sveriges lantbruksuniversitet ed. Dahlgaard, Cs deposited by the Chernobyl fallout in 1986 in the Nordic countries

4 Sveriges lantbruksuniversitet The study area were located in Heby commune, 40 km northwest of Uppsala in Sweden. study area was on a rocky boreal forest; dominated by - Scots pine - Norway spruce - shrub species

5 Sveriges lantbruksuniversitet Aim of study: Was to investigate the long-term effects of a single potassium (K) fertilizer in boreal forest ecosystems on 137 Cs uptake by heather and fungi 1992 – 2009, 17 year

6 Sveriges lantbruksuniversitet Pools and processes in soil where Caesium is involved

7 Sveriges lantbruksuniversitet Soil: The soil type was a Haplic Podzol on sandy glacial till with mor humus type organic matter content in upper layer about 70% pH extractable K 480 – 35 mg/kg

8 Sveriges lantbruksuniversitet Treatment in field: K+, fertilized area - about 1.0 ha 100 kg K/ha, 1992, once as a single dose K-, control area - about 1.0 ha K = potassium The ground deposition of 137 Cs 1986 was kBq m 2

9 Sveriges lantbruksuniversitet Sampling Auguste-September Lingonberry, Bilberryand and Heather - the green parts were cut above ground The sporocarps of fungi: Lactarius rufus (Pepparriska), Suillus variegatus (Sandsop), Rozites caperata (Rödskivig kanelspindelskivling) Cortinarius semisanguineus (Rynkad tofsskivling)

10 Sveriges lantbruksuniversitet Lactarius rufus, Pepparriska Suillus variegatus, Sandsop Rozites caperata, Rynkad tofsskivling Cortinarius semisanguineus, Rödskivig kanelspindelskivling

11 Sveriges lantbruksuniversitet Herbs plant was dried at o C, milled and sieved (2 mm) Sporocarps of fungi was dried at 55 o C milled and sieved (2 mm) The 137 Cs activity (Bq/kg, d.w.) were determined with HPGe detectors and decay corrected to sampling date All statistical analyses were carried out using Minitab software Samples preparation:

12 Sveriges lantbruksuniversitet Results: Mean 137 Cs activity concentration (Bq/kg d.w.) The effect of K+ and K- K+ area showed a highly significant decrease in 137 Cs activity (40-60%) compared with plants grown on K- area Plant speciesK+SEnK-SEn % Lingonberry1 295 ± ± Bilberry1 409± ± Heather4 563± ±

13 Sveriges lantbruksuniversitet 137 Cs (Bq/kg d.w.) activity concen- trations in vaccinium vitis-idaea, lingonberry n =

14 Sveriges lantbruksuniversitet 137 Cs (Bq/kg d.w.) activity concen- trations in Vaccinium myrtillus, Bilberry n =

15 Sveriges lantbruksuniversitet 137 Cs (Bq/kg d.w.) activity concen- trations in Calluna vulgaris, Heather n =

16 Sveriges lantbruksuniversitet 137 Cs activity concentration before and up to 15 months after the K fertilizer application (expressed as % of 137 Cs activity concentration in plants grown on control area). = Heather = Bilberry = Lingonberry

17 Sveriges lantbruksuniversitet T eff (years), effective ecological half-life The ecological half-life of radiocaesium (time taken for a given activity to decrease to half of the original value) Control area: 11y for lingonberry & bilberry 9y for heather

18 Sveriges lantbruksuniversitet Effect of K-fertilization in plants the effect was very clear for about 7 years, Cs activity concentration in K-fertilized are compared with the control area show a reduction with: 53% for lingonberry 63% for bilberry 69% for heather

19 Sveriges lantbruksuniversitet Schematic view of fungi in forest soil and its connection through the mycelia with roots ≈ 10% Mycorrhizal fungi play a fundamental role in forest ecosystems and they are involved in nutrient cycling

20 Sveriges lantbruksuniversitet 137 Cs (Bq/kg d.w.) activity concentra- tions in Cortinarius semisanguineus,

21 Sveriges lantbruksuniversitet 137 Cs (Bq/kg d.w.) activity concentrations in Suillus variegatus, Sand Soup n =

22 Sveriges lantbruksuniversitet

23 Sveriges lantbruksuniversitet Conclusion The results show that a single application of K- fertilizer (100 kg K/ha) to boreal forest plants is an effective way to decrease 137 Cs activity concen- trations in plants over a period 17 yare K-fertilizer decreased 137 Cs in heather, lingonberry and bilberry even the first year The most pronounced and significant reduction occurred over the first 7-8 years The reduction on 137 Cs in fungi after K fertilization was less pronounced, but still statistically significant

24 Sveriges lantbruksuniversitet TACK END

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