Phosphorus (P) was first discovered by Hennig Brandt in Germany in 1669. It is ironic that the discovery was made when he was busy with an experiment with urine, sand and coal. Phosphorus is absorbed by the plant from the nutrient solution in the form of H2PO4-1 or HPO4-2 at pH values between 4.5 and [...]

Nitrogen is consumed in large amounts by the plant. Nitrogen is used in components such as amino acids all proteins enzymes co enzymes nucleic acids and chlorophyll. Dry weight analysis of plant material shows that on average nitrogen makes up about 6% of the dry weight. Nitrogen is taken up in two forms; nitrates (NO3-) [...]