Drainage losses of sulphur from a yellow-grey earth soil

Abstract

Abstract Losses of sulphur (S) in surface runoff and subsurface drainage waters were measured during a 2-year study on a grazed yellow-grey earth soil (Tokomaru silt loam). Dissolved sulphur (S) losses in subsurface drainage from pastures fertilised the preceding spring averaged 11.0 ± 3.5 kg S/ha per year. Application of 43 kg S/ha in late autumn-early winter increased dissolved S losses by 4.5 ± 1.5 kg S/ha. Dissolved S concentrations in the drainage were significantly correlated with water-soluble soil S, but total dissolved S losses were not. Losses of dissolved S in surface runoff were markedly affected by fertiliser addition and subsurface drainage. Losses from gently sloping (6°) plots were minimal except when fertiliser S was applied in late autumn to undrained pastures. Under these conditions, 8% (4.5 kg S/ha) of the applied superphosphate was lost in surface runoff during a 6-week period. In another study, where dissolved superphosphate was applied in autumn, 130/0 (7.2 kg S/ha) of the applied S...