(a) Discuss the cultivation of cassava under the following headings: (i) soil requirements; (ii) spacing (iii) one disease; (iv) one pest. [5 marks] (b) Dif...

Answer Details

(a) Cultivation of cassava

• (i) Soil requirements: deep, loose, well-drained sandy-loam soil, fairly fertile and free of waterlogging.
• (ii) Spacing: about 1 m x 1 m (one metre between rows and one metre within rows).
• (iii) One disease: cassava mosaic disease.
• (iv) One pest: cassava mealybug (or grasshopper/variegated grasshopper).

(b) Difference between natural and artificial pasture

A natural pasture is grassland made up of grasses and herbs that grow on their own without being deliberately planted by man, whereas an artificial (established) pasture is one that is deliberately planted and managed by man using selected grasses and legumes.

(c) Disease as used in crop production

A disease is any abnormal condition that disturbs the normal structure or functioning of a crop plant, caused by pathogens such as fungi, bacteria and viruses or by unfavourable conditions, leading to reduced growth and yield.

(d) Mendel's law of independent assortment

It states that when two or more pairs of contrasting characters (genes) are considered together, each pair separates and is inherited independently of the others during the formation of gametes.

(e) Regeneration as a forest management practice

Regeneration is the renewal or re-establishment of a forest, either naturally (from seeds and shoots of existing trees) or artificially (by deliberately planting seedlings), to replace trees that have been removed and keep the forest productive.

(f) Five effects of deforestation

1. It leads to soil erosion.
2. It reduces soil fertility (loss of organic matter and leaching).
3. It destroys the habitat of wildlife, reducing biodiversity.
4. It reduces rainfall and alters the climate.
5. It causes desertification and loss of timber and forest products.