(a) What is natural pasture? (2 marks) (ii) State four characteristics of natural pastures in West Africa. (4 marks) (b) Discuss the root knot disease of to...

(a)(i) Natural pasture [2 marks]

Natural pasture is grassland made up of grasses, legumes and other herbs that grow on their own (naturally) without being deliberately planted or managed by man, and on which animals graze.

(a)(ii) Four characteristics of natural pastures in West Africa [4 marks]

• They are made up mainly of grasses with few legumes.
• They are dominated by tall, coarse grasses of low nutritive (feeding) value.
• They grow luxuriantly in the rainy season but dry up and become poor in the dry season.
• They contain a mixture of many different (unimproved) species and are often subject to bush burning.

(b) Root-knot disease of tomato [6 marks]

• (i) Causal organism: a nematode (eelworm), Meloidogyne species.
• (ii) Mode of transmission: spread through infested soil, and through movement of infected seedlings, farm tools, irrigation/run-off water and soil carried on implements or feet.
• (iii) Two symptoms: formation of knots, galls or swellings on the roots; stunted growth with yellowing and wilting of the plant (poor yield).
• (iv) Two control measures: practise crop rotation and use resistant varieties; treat/sterilise the soil with nematicides and destroy (uproot and burn) infected plants.

(c) Grafting versus budding [2 marks]

In grafting, a portion of stem (scion) bearing several buds is joined onto the rootstock, whereas in budding only a single bud is inserted into the bark of the rootstock.

(d) Two uses of sugarcane [2 marks]

• It is used for the production of sugar and syrup.
• It is chewed as food and used in making alcohol/ethanol and animal feed (by-products such as molasses).