(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) 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) 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.