Theory question 103
Agricultural Ecology(a) Draw a well labelled diagram of the water cycle.
(b) Mention two deficiency symptoms of phosphorus in crops.
(c) Using the table below, classify the following insect-pests according to their modes of feeding: (i) weevil; (ii) locust; (iii) scale insect; (iv) armyworm; (v) earworm; (vi) cotton stainer; (vii) green spidermites; (viii) thrips; (ix) capsids; (x) yam beetle.
Show the model answer
(a) Diagram showing: sea/rivers/lakes; evaporation and transpiration from plants; water vapour rising and condensing into clouds; precipitation (rain); run-off back into rivers; infiltration/percolation into soil and ground water; arrows completing the cycle.
(b) Any two: poor root development; stunted growth; purplish/dark-green leaves; delayed maturity; poor flowering, fruiting and seed formation.
(c) Biting and chewing: locust; armyworm; yam beetle. Piercing and sucking: scale insect; cotton stainer; green spider mites; thrips; capsids. Boring: weevil; earworm.
Label every process with an arrow in the water cycle.