Appears in
Oxford Companion to Wine

By Jancis Robinson

Published 2006

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phosphorus, one of the most important mineral elements required for vine growth, yet the amounts required are sufficiently small that for most vineyards, the natural supply from the soil is enough. There is only about 0.6 kg of phosphorus in a tonne of grapes (1.3 lb per ton). Phosphorus in the vine is an essential component of compounds involved in photosynthesis and sugar–starch transformations as well as the transfer of energy. Phosphorus deficiency in vines is uncommon, and found mostly on soils with a large content of iron and aluminium oxides, as in parts of the Yarra and King valleys in victoria, Australia, and the willamette valley, Oregon, USA. Its symptoms are a gradual loss of vigour and, sometimes, some red spots on the leaves.