%A Sissel Hansen %A Anne Kjersti Bakken %J Proceedings of the 2nd scientific conference of the international society of organic agriculture research (ISOFAR), Livestock, socio-economic and cross disciplinary research in organic agriculture %T A discussion of norms for S supply in organic farming based on content in forage and ruminant performance in Norway %X The content of sulphur (S) in grassland on 27 Norwegian organic farms with dairy or sheep production was investigated in 2001 and 2002. The forage content of S was below the norms (2 g S kg DM-1) for both plants and animals in a large proportion of the samples. The average S content in forage at dairy farms was 1.4 g S kg DM-1 and at sheep farms 1.5 g. Even on grasslands with low plant S content (<1 g S kg DM-1), S-fertilization did not increase yields and increased the plants? S content only very slightly. No indications of S deficiency were observed on the dairy farms. For one sheep farm with a forage S content of 1.1 ? 0.1g S kg DM-1, brittle and short winter wool was reported. %K forage, dairy cattle, deficiency, grassland, ruminant, sheep, mineralsip %P 160-163 %E Daniel Neuhoff %V II %D 2008 %I ISOFAR %L orgprints11946