20 YEARS USE OF SELENIUM IN FERTILIZER Status from Finland

1
20 YEARS USE OF SELENIUM IN FERTILIZERStatus
from Finland

• Mikko Korhonen
• Kemira GrowHow Oyj
• Helsinki, Finland

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Se history in Finland

• Se question rose in 60s
• Importance of Se in animals was demonstrated in
  researches
• Animal symptoms (sitting pigs muscular
  problems)
• gt 1969 inorganic Se allowed to used in feeds
• gt all commercial feeds supplemented (sodium
  selenite)
• gt decreased symptoms in animals fed commercial
  feeds
• Only minor effect on human Se intake
• Transfer of inorganic Se into animal products is
  poor
• HOW TO FULFIL Se REQUIREMENTS OF HUMAN AS
  COMPREHENSIVE AND SAFE WAY AS POSSIBLE ?

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Se history in Finland

• Intensive research project started
• Collaboration between companies, authorities and
  research
• Se-transfer to plants through various means of
  applications ?
• Se-transfer from feeds to animal products ?
• Human Se supply and intake ?
• -gt Low Se content in soil, pH and organic matter
  reduces Se availability (Se into insoluble form
  from selenate to selenite)
• -gt foliar application very difficult to control
  (toxicity)
• -gt organic Se transfer into animal products gtgt
  inorganic
• -gt selenate better than selenite in feeds
• -gt Se addition into fertilizers started1984
  (sodium selanate)
• 1984-1989 6 and 16 mg/kg DM, 1990 all 6 mg/kg,
  1998 10 mg/kg all

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Effects of Se applications
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Effects of Se applications
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Effects of Se applications
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Se in animals

• Essential trace element
• Toxic substance
• gt Constant monitoring of content in diets
• Biochemical component of enzymes, proteins and
  hormones
• Muscular function, heart disease, fertility,
  growth, resistance
• Utilization of organic Se gt inorganic Se
• Cattle 0.1, pigs 0.2, poultry 0.1-0.21, fur
  animals 0.6-0.9 mg/kg DM
• Max in compound feeds 0.5 mg/kg DM
• 0.2 in SE, 0.3 in NRC
• Surplus supply excreted in urine

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Se in plants

• Not essential element
• Plants has a key role to circulate Se from soil
  to animal and humans
• Why Se is taken up if not needed ?
• Plants form also volatile Se compounds
• Inorganic to organic (protein bound
  Se-methionine)
• Oxidation reduction processes
• May delay senescene
• May improve utilization of short wavelength light
• May improve assimilation
• May improve product quality starch content,
  colour
• Also plants requires Se ?? (beneficial or even
  essential)

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Grass Se in farm scale studies
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Grass Se in farm scale studies
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Se in Finland

• Se application in fertilizers
• SAFE AN ACCURATE WAY to fullfill Se requirements
• Soil-crops-animal products-human
• In all fertilizers 10 mg/kg DM
• 5 g/ha increased the content up to the current
  level
• Grasses and cereals for each cut
• In general grass content 0.2-0.3 mg/kg DM
• Enough to cover requirements of cattle
• Organic produced products or feeds Se content
  very low
• Silage 0.02, cereals lt 0.01
• Se in manure ?
• Role of Se in plants active research going on