Question

3(a) Discuss the root knot disease of tomato plants under the following headings: (i) causal organism; (ii) mode of transmission; (iii) two symptoms; (iv) two prevention and control measures.
(b) Describe three effects each of the following farming practices on the soil: (i) fertilizer application; (ii) clean clearing; (iii) overgrazing.
(c) Mention three agricultural uses of land.

Accepted Answer

(a)(i) Causal organism: Root knot nematode/Meloidogyne spp.
(ii) Mode of transmission: Nematodes are soil borne/through the soil.
(iii) Symptoms: Enlargement of certain cells of the roots in form of knots; Wilting of plants; Retarded growth; Reduction in yield.
(iv) Prevention and control measures: Practising crop rotation; Good farm sanitation; Use of resistant varieties; Soil sterilization; Use of nematicides.

(b)(i) Fertilizer application effects: Adds nutrients to the soil/enhances the productive capacity of the soil; Continuous use of nitrogenous fertilisers e.g. sulphate of ammonia increases soil acidity; Excessive use of fertilisers reduces the availability of some essential plant nutrients e.g. potassium and calcium; Prolonged use of fertilizers leads to a reduction in some soil microorganisms; Excessive use of fertilizers leads to ground-water contamination.
(ii) Clean clearing effects: Destruction of soil structure/soil compaction; Exposes the soil to erosion; Encourages leaching of soil nutrients; Results in increased rate of evaporation; Leads to increase in soil temperature.
(iii) Overgrazing effects: Leads to soil compaction; Exposes the soil to agents of erosion; Increases the evaporation rate of soil water; Results in low soil fertility; Destroys soil structure.

(c) Agricultural uses of land: Crop production; Wildlife conservation/game reserve; Livestock production farming; Forestry; Horticulture/snail farming.

WAEC Agricultural Science 2023 Theory — Question 3

Sign up free to unlock