(a) Explain the following terms used in agricultural ecology: (i) Soil texture (ii) Soil profile. (b) (i) Discuss three advantages of grafting. (ii) Mention...

(a) Terms in agricultural ecology:

• (i) Soil texture: The relative proportion (by weight) of the different sizes of mineral particles - sand, silt and clay - that make up the soil. It determines whether a soil is sandy, loamy or clayey.
• (ii) Soil profile: A vertical section of the soil from the surface down to the parent rock, showing the different layers or horizons (topsoil, subsoil, weathered rock and parent material).

(b)(i) Three advantages of grafting:

• It combines the good qualities of the rootstock (for example disease resistance) with those of the scion (good fruit).
• The new plant matures and bears fruit earlier than one raised from seed.
• It keeps the desired variety true to type (the offspring resembles the parent exactly).

(b)(ii) Two crops that could be propagated by grafting:

• Mango
• Citrus (orange) (or cocoa/cashew)

(c) Four cultural practices used to replenish nutrients in the soil:

• Application of organic manure (farmyard manure, compost, green manure).
• Application of inorganic fertilisers.
• Crop rotation, including legumes that fix nitrogen.
• Bush fallowing/cover cropping to allow the soil to recover.

(d) Four measures to control pests in grain stores:

• Dry the grains properly to a safe moisture content before storage.
• Fumigate or dust the grains with approved storage chemicals/insecticides.
• Keep the store clean, dry, airtight and rat-proof (good hygiene).
• Mix the grains with inert materials such as wood ash, or store in hermetic (airtight) containers.