PHOSPHORUS (P)
Phosphorus is very mobile in plants; relatively immobile in soil and does not leach. It is stored in seeds and fruit. It
is most readily available to plants between a pH of 6 and 7.5 (unavailable in very acid or alkaline soils). Found in
greatest concentration in sites of new cell growth. Phosphorus absorption is reduced at low soil temperatures.
Phosphorus is necessary to stimulate early root formation and growth, hasten crop maturity, stimulate flowering and
seed production, give winter hardiness to fall plantings and seedings, and promote vigorous start (cell division) to
plants.
Phosphorus has a role in fat, carbon, hydrogen, and oxygen metabolism, in respiration, and in photosynthesis.
Deficiency symptoms
General: Red or purplish color (anthocyanin pigment) in leaves, especially undersides. Death of tissue or necrosis
may follow. Root growth poor. Lower stems may be purplish. Plants may exhibit stunting and delayed maturity.
Loss of lower leaves. May exhibit reduced flowering.
Deficiency is often a problem in cool soils in early spring.
Crops: corn has purplish tint, legumes bluish green and stunted, tomato has yellowing of leaves, appearance of
purpling on underside of leaf, and delayed maturity.
Turf: reddish-purple cast appears from the tip of the leaf blades (especially apparent in cool weather), dull blue-
green color, poor growth. Sod slow to knit. Fescue leaves have a cupped appearance.
Broadleaf plants: Leaves are green to dark green. Veins, petioles, and lower surfaces may become reddish, dull
bronze, or purplish. Foliage may be sparse, slightly smaller than normal, and distorted. Leaves drop early. Shoots
are normal in length unless the deficiency is severe, but they may be small in diameter.