(a) In a tabular form, briefly discuss the following plant nutrients: (i) Potassium; (ii) Phosphorus; (iii) Calcium. Under the following headings: (i) form in which it is absorbed; (ii) three functions; (iii) one deficiency symptom.
(b) Give two examples of nitrogenous fertilizers.
Explanation
(a)
|
PLANT NUTRIENT |
FORM IN WHICH IT IS ABSORBED | FUNCTION |
DEFICIENCY SYMPTOMS |
|
Potassium |
Potassium cation/k+ |
-associated with enzymatic activities. It contributes in controlling stomata) opening and thus water movement in – Important in metabolism and translocation of carbohydrates. – important in neutralizing plant acids. – It strengthens plant stems and aids the uptake of nitrates |
– retarded growth. – premature loss of leaves |
|
Phosphorus |
– Phosphate anion p0³-₃ -P₂0₅ |
– It is associated with enzymatic actions. – It is also an important constituent of nuclear protein. – It strengthens the plants’ skeletal structure. – It confers on plants the ability to ward off diseases. – It is essential for cell division; – essential for root development; – essential for food formation. – It hastens the ripening of fruits. |
– plant becomes purple – stunting of plant parts. – poor root and bark development. – flowers, fruits and seeds fail to form. |
|
Calcium |
Calcium cation/Ca2+ | – It is important in cell wall formation. – It is also essential for growth of roots. – it controls toxicity of Al³⁺,Mn³⁺, and Na+. – It is equally important in translo-cation and storage of food into tubers/seeds. – It neutralizes acids in plants and takes part in metabolic activities. |
– stunting of roots. – leaves turn yellowsh |
(b) Examples of nitrogenous fertilizers are: (i) urea (ii) ammonium sulphate (iii) sodium nitrate (iv) calcium ammonium nitrate (CAN)