AGRONOMIJAS VĒSTIS - Latvijas Lauksaimniecības universitāte

AGRONOMIJAS VĒSTIS (Latvian Journal of Agronomy), No.10, LLU, 2008SOIL SCIENCE, PLANT, FERTILIZER AND FIELDMANAGEMENTIMPACT OF AGROCHEMICAL AND CLIMATIC FACTORS ON SELENIUMCONCENTRATION IN SOILSAntanaitis A., Lubyt÷ J., Antanaitis Š.Agrochemical Research Centre of Lithuanian Institute of Agriculture,Savanorių 287, LT-50127, Kaunas, Lithuania, analize@agrolab.ltAbstractSelenium was extracted by boiling the soil sample in concentrated HNO 3 ina closed systemfor 2 hours. Soil and acid ratio 1:10. The extracted selenium amount was measured using atomicabsorption spectrometer with graphite furnace (Aanalyst 800). Determined average seleniumconcentration was within a range of 0,129 - 0,180 mg kg -1 .Selenium concentration tends to be higher in the regions with higher average annual precipitationlevel (up to 800 mm) and higher han average annual temperatures. Long-lasting (30 years) NPKfertilisation resulted in a increased accumulation of selenium in the soil, while after the 8 year-longNPK fertilisation only a tendency of selenium concentration increase was recorded. Higherselenium concentration was determined in light texture soils with higher concentration ofpotassium and pH value within the range of 5,1-6,0.Key words:Fertilisation, potassium, precipitation, selenium, soil.IntroductionWide scale research on selenium concentration in soil, plants and other objects was startedlast in the century. In the beginning the selenium issue was viewed only from the toxicity point,and then it was found, that selenium impedes liver necrosis in rats (Swarz et all., 1957). Researchon selenium concentration in soil was started even later. Till now selenium concentration inLithuanian soils was studied very little. Researchers have not yet come to a unanimous opinionconcerning selenium concentration dependence on soil physical and agrochemical properties.Dudka ascertained a positive relation between selenium concentration and the volume of clayparticles in soil (Dudka 1991). German researchers noticed that bioavailability of seleniumincreases together with increasing pH value (Muller et all., 2003). In Hungary, according to theresults of selenium extraction using 0,5 M HNO 3 , 11 % of soils contain more than 1,0 mg kg -1 ofselenium. No relation was found between humus amount in soil and selenium concentration(Regional Office for Europe, 1989). On the other hand plants accumulate different concentrationsof selenium in the same conditions (Kabata-Pendias, 1998). Selenium concentration is not the samein separate layers of different Indian soils – top layer of low salinity soil contains more seleniumthan the deeper layers (Sharma, 1985). 10 years-long intensive fertilisation of perennial grasseswith sludge (selenium application rate 250 g ha -1 ) and mineral fertilisers (selenium 150 g ha -1 ) inAustria resulted in selenium concentration increase only in top 0-2,5 and 2,5-5,0 cm soil layers(Edelbauer et all., 2001) Precipitation adds certain amount of selenium to soil. Soils located closerto the sea contain more selenium (Щелкунов, 2000). Selenium deficiency is observed in Europeannon-chernozem zone despite the fact that selenium concentration in rocks and soil is sufficient(Ermakov, 1992). Selenium content in soil is studied in many countries dealing with selenium –related problems. Researchers attempt to decrease selenium accumulation in plants in countrieswith selenium – rich soils, and to increase it, if selenium content in soils is too little (Amweg,2003). The aim of our study is to determine selenium concentration in soils and to assess seleniumrelation to soil agrochemical properties as well as to climatic factors.20