Phosphorus (P) | Mineral element vital to plant growth. One of three macro-nutrients (‘NPK‘) needed for photosynthesis and overall plant health and yield (eg. wine grapes). See also nitrogen and potassiumCalcareous soils whose clay content is high may be low in phosphorus (Ian d’Agata, 2019, p.337)

Bibliography

Dr Ian d’Agata, Native Wine Grape Terroirs of Italy (University of California Press, 2019).