Theory question 103
Soil Fertility and Plant Nutrition(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.
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(a) Potassium – absorbed as K+; functions: strengthens stems, aids starch and sugar formation and movement, increases disease resistance, regulates stomata and water; deficiency: scorching/browning of leaf margins and tips of older leaves, weak stems
Phosphorus – absorbed as H2PO4−/HPO42−; functions: root development, flowering, fruiting and seed formation, early maturity, energy transfer (ATP); deficiency: purple colour on leaves, stunted growth, poor roots, delayed maturity
Calcium – absorbed as Ca2+; functions: forms cell walls (calcium pectate), growth of root and shoot tips, neutralises acids, pod filling in groundnut; deficiency: death of growing tips, distorted young leaves, blossom-end rot, empty groundnut pods
(b) Any two: urea; ammonium sulphate; ammonium nitrate; calcium ammonium nitrate; sodium nitrate
Put the three nutrients in rows under the three headings.