Boron content of sultana vines in the Mildura area

Abstract

Sultana vines on Mallee soils in the Mildura district show a high boron content, which frequently reaches toxicity levels. The concentration of boron in the vine is related to the soil type, and is highest on loam soils, lowest on sands. Vines on grey alluvial soils in the area show lower, but adequate, boron content. Boron accumulates principally in the lamina of the leaf, where there is a rapid increase in concentration during the growing season. symptoms of boron toxicity on sultana leaves are described. These symptoms are found on leaves with 300 p.p.m, boron or more. Agricultural tile drains play a big part in keeping boron concentrations below toxicity levels. Drainage waters commonly show 5 p.p.m. boron. Data collected suggest that applications of sulphate of ammonia and superphosphate tend to increase the level of boron in sultana leaves.