It also causes a black or brown inter-veinal necrosis and leaves curl upwards. With a phosphorus deficiency, fruit is small. It is very important to root crops, a deficiency inhibits fruiting, dark or purplish discoloration of leaves. Fe are both crucial. Only dissolved is available and in alkaline media it precipitates most phosphate as calcium or magnesium salts.
Excess phosphorus precipitates with iron, reducing available iron.
It becomes a part of many important organic compounds. Phosphorus can become unavailable in high acid conditions, or dry media or soils. Bone undergoes remodeling and turnover. The ratio is needed for minerals to be efficiently used by the body. Niacin and riboflavin cannot be digested without phosphorus.