Sulpur deficiency of dry land lucerne in the eastern Darling Downs of Queensland

Abstract

Experiments to study the phosphorus, molybdenum and sulphur requirements of lucerne swards were conducted at six sites on the eastern Darling Downs, Queensland. The soils at all sites were derived from basalt. The swards did not respond to phosphorus at any of the sites and responded to molybdenum at only one. Sulphur deficiency was more severe in late winter-early spring than in summer. Lucerne response to added sulphur was not related to total soil sulphur and only partly related to available soil sulphur or water soluble soil sulphate. Five lucerne swards on black earths showed decreasing sulphur deficiency with increasing soil depth and increasing soil salinity. On one site annual medics were more severely affected by sulphur deficiency than was the deeper rooting lucerne.