Correction of manganese deficiency in barley crops on calcareous soils. 1. Manganous sulphate applied at sowing and as foliar sprays

Abstract

Barley was grown in six field experiments from 1963 to 1969 on calcareous (>80 per cent CaCO3) soils of southern Yorke Peninsula, South Australia. Manganous sulphate was applied to the soil at sowing at 0 to 16 kg ha-1 Mn and to the plants as foliar sprays (1.3 - 1.8 kg ha-1 Mn per application). The effects on shoot and root growth, and manganese uptake in the shoots were measured during the season, and grain yields were determined. Application of manganous sulphate to the soil at sowing increased shoot and root growth and the manganese content of the shoots, and progressively delayed the appearance of manganese deficiency symptoms. However, all crops showed symptoms by the time of stem extension irrespective of the amount of manganese applied to the soil. The maximum grain yield response to soil application was obtained with 6 kg ha-1 Mn. Foliar application of manganous sulphate delayed the appearance of deficiency symptoms and increased grain yield in three of the experiments. Two or three sprays were more effective than a single spray, particularly where no manganese was applied to the soil at sowing. A combination of both soil and foliar application of manganous sulphate (6 kg ha-1Mn added to the soil at sowing and two or three foliar sprays) produced the highest grain yields and usually prevented the occurrence of deficiency symptoms.