https://farmingfirst.org/2011/01/selenium-fortified-fertilizers-in-finland/ https://farmingfirst.org/2011/01/selenium-fortified-fertiliz... Apparently Finland

https://farmingfirst.org/2011/01/selenium-fortified-fertilizers-in-finland/ https://farmingfirst.org/2011/01/selenium-fortified-fertiliz... Apparently Finland made it mandatory, and it worked.