Phosphates

Phosphates are organic and inorganic compounds of the chemical element phosphorus (P), which exist in many forms. In the narrower sense, the term refers to the salts of phosphoric acid (H₃PO₄). In plant physiology, inorganic phosphates play an important role alongside nutrients in various essential processes such as osmosis regulation, ion transport, photosynthesis and protection against diseases (as do chlorides, nitrates and sulphates). There are the following compounds with the listed functions:

• Aluminium phosphate (AlPO₄) - fertiliser for plant health and soil structure
• Calcium phosphate (Ca₃(PO₄)₂) - cell growth; root development; resistance to diseases
• Iron(III) phosphate (FePO₄) - electron transport photosynthesis; energy production; oxygen transport
• Potassium phosphate (K₃PO₄) - regulation of energy balance; nutrient transport; growth; stress resistance
• Magnesium phosphate (Mg₃(PO₄)₂) - chlorophyll production; boosting photosynthesis performance
• Sodium phosphate (Na₃PO₄) - osmotic pressure for water balance; nutrient uptake; vitality

Another inorganic phosphate is silver phosphate (Ag₃PO₄). This is used in water treatment to eliminate unwanted microorganisms. Most of these phosphates can also be found in small quantities in soil and water. Above a certain level, they can lead to environmental problems such as eutrophication (ancient Greek eutroph = well nourished, excessive supply of nutrients, especially nitrogen and phosphorus compounds).