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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 www.slu.se Klas Rosén Department of Soil and Environment SLU – Uppsala Sweden E-mail: klas.rosen@slu.seklas.rosen@slu.se 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 www.slu.se 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 www.slu.se ed. Dahlgaard, 1994 137 Cs deposited by the Chernobyl fallout in 1986 in the Nordic countries

4 Sveriges lantbruksuniversitet www.slu.se 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 www.slu.se 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 www.slu.se Pools and processes in soil where Caesium is involved

7 Sveriges lantbruksuniversitet www.slu.se 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 3.4 - 3.7 extractable K 480 – 35 mg/kg

8 Sveriges lantbruksuniversitet www.slu.se 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 35 - 40 kBq m 2

9 Sveriges lantbruksuniversitet www.slu.se Sampling 1992-2009 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 www.slu.se Lactarius rufus, Pepparriska Suillus variegatus, Sandsop Rozites caperata, Rynkad tofsskivling Cortinarius semisanguineus, Rödskivig kanelspindelskivling

11 Sveriges lantbruksuniversitet www.slu.se Herbs plant was dried at 80-90 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 www.slu.se Results: Mean 137 Cs activity concentration (Bq/kg d.w.) 1992-2009 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 ±8390 2 162±11159 40 Bilberry1 409±11486 2 691±16062 47 Heather4 563±3148911 584±58764 60

13 Sveriges lantbruksuniversitet www.slu.se 137 Cs (Bq/kg d.w.) activity concen- trations in vaccinium vitis-idaea, lingonberry n = 12 - 3

14 Sveriges lantbruksuniversitet www.slu.se 137 Cs (Bq/kg d.w.) activity concen- trations in Vaccinium myrtillus, Bilberry 1992-2009 n = 11 - 3

15 Sveriges lantbruksuniversitet www.slu.se 137 Cs (Bq/kg d.w.) activity concen- trations in Calluna vulgaris, Heather 1992-2009 n = 13 - 3

16 Sveriges lantbruksuniversitet www.slu.se 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 www.slu.se, 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 www.slu.se Effect of K-fertilization in plants the effect was very clear for about 7 years, 1993 -2000 137 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 www.slu.se 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 www.slu.se 137 Cs (Bq/kg d.w.) activity concentra- tions in Cortinarius semisanguineus, 1992-2009

21 Sveriges lantbruksuniversitet www.slu.se 137 Cs (Bq/kg d.w.) activity concentrations in Suillus variegatus, Sand Soup 1992-2009 n = 33 - 1

22 Sveriges lantbruksuniversitet www.slu.se

23 Sveriges lantbruksuniversitet www.slu.se 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 www.slu.se TACK END


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