Question

3(a) Give one function each of the following bacteria in the nitrogen cycle: (i) Rhizobium; (ii) Nitrosomonas; (iii) Pseudomonas; (iv) Nitrobacter.
(b) A farmer discovered that aphids have invaded a cowpea farm. (i) State three effects of aphids on the cowpea plants. (ii) Mention four cultural ways by which the farmer could control aphids on the cowpea farm.
(c)(i) Explain the term forestry. (ii) Name five products that could be obtained from forests.

Accepted Answer

(a)(i) Rhizobium: fixation of nitrogen in the root nodules of leguminous crops.
(ii) Nitrosomonas: oxidation of ammonium compounds to nitrites (NO2-).
(iii) Pseudomonas: reduction of soil nitrates to gaseous nitrogen/denitrification.
(iv) Nitrobacter: oxidation of nitrites to nitrates (NO3-).

(b)(i) Effects of aphids on cowpea: reduces yield; reduces yield of seeds; reduces germination of seeds/seed viability; serves as vectors of diseases; may result in death of plants.
(ii) Cultural control: planting resistant varieties; planting insect-free seeds; practising crop rotation; inter-planting of crops.

(c)(i) Forestry is the study and management of forests and forest resources -- the art and science of managing trees, forests and forest products for human use.
(ii) Products from forests: Timber/wood; Fuelwood/firewood; Woodpulp; Honey; Snail/Mushroom; Chewing stick; Palm wine/palm oil/Kolanut; Wild fruits; Bamboo; Gum/Latex; Medicinal herbs; Dye; Wild vegetables; Fibre; Resin; Bush yam; Long pole; Wax; Wild spice (any five).

WAEC Agricultural Science 2024 Theory — Question 3

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