Correction of zinc deficiency in linseed on the Darling Downs, Queensland

Abstract

Significant yield increases were obtained from the application of zinc sulphate sprays at critical times. The effect of spray concentration (0· 5, 1·0 and 1·5%) and frequency of spraying (single or dual applications) was not significant. To be fully effective, sprays had to be applied at 2 weeks after emergence. Soil applications of 1 cwt of zinc sulphate per acre were fully effective. The lower rates of 28 and 70 lb/ac were not fully effective in all trials. The practical implications of these findings is that zinc sulphate sprays applied at 1·0% at 10 gal/ac at 2 weeks after emergence will control zinc deficiency in linseed at a low cost.