(a) Discuss the cultivation of cassava under the following headings: (i) soil requirements; (ii) spacing (iii) one disease; (iv) one pest. [5 marks]
(b) Differentiate between natural pasture and artificial pasture. [2 marks]
(c). Explain the term disease as used in crop production. [2 marks]
(d) State Mendel’s law of independent assortment of genes. [2 marks]
(e) Explain the term regeneration as a forest management practice. [2 marks]
(f) State five effects of deforestation. [5 marks]
Explanation
(a) Discussion of the cultivation of cassava:
(i) Soil requirements:
-A well-drained/sandy/friable loamy soil.
- soil rich in organic matter.
(ii) Spacing: 1m x 1m. (iii) Disease:
- Cassava mosaic
- Leaf spot
- Bacterial leaf blight
- Tuber rot/white thread
-Anthracuose.
(iv) Pest:
- Green spider mites
- Grasshoppers
- Mealy bugs
- Rodents
- White flies
- Monkeys.
(b) Difference between natural and artificial pasture: Natural pasture refers to an area of land covered with forage grasses and legumes which are not planted by man. While/on the other hand/but/whereas. Artificial pasture refers to an area of land covered with forage grasses and legumes which are deliberately planted by man.
(c) Explanation of the term disease in crop production: Disease refers to a deviation from the normal health status/ condition of a crop presenting marked symptoms.
(d) Mendel 's law of independent assortment of genes: Mendel 's law of independent assortment of genes states that each character behaves as a separate unit and is inherited independently of any other character. OR This law states that when two pure/true-bred organisms with two or more pairs of contrasting characters are crossed, the characters assort independently in the second filial generation.
(e) Explanation of regeneration as a forest management practice: - Regeneration is the process of forest regrowth after it has been exploited which can be natural or artificial.
(f) Effects of deforestation:
- Loss of soil nutrients.
- Permanent destruction of indigenous forests.
- Soil erosion.
- Desert encroachment desertification.
- Loss of bodiversity/imbalance in the ecosystem.
-Disruption of hydrological cycle.
- Increase in atmospheric carbon(iv) oxide concentration.
-Destruction of micro climate/increased environmental temperature.
- Loss of soil organic matter.
- Reduction in soil microbial activities.
-Exposure of the soil to direct rays of the sun.