(a)(i) State six uses of lime in Agriculture (ii) List four common liming materials (b) State (i) Three examples of nitrogenous fertilizer: (ii) three examp...

Answer Details

(a)(i) Six uses of lime in agriculture:

1. It reduces soil acidity by raising the soil pH.
2. It supplies the plant nutrients calcium and (in dolomite) magnesium.
3. It improves soil structure by causing clay particles to floculate, giving better aeration and drainage.
4. It promotes the activity of soil micro-organisms and hastens decomposition of organic matter.
5. It increases the availability of other nutrients such as phosphorus and molybdenum in acid soils.
6. It reduces the toxicity of iron, aluminium and manganese in strongly acid soils, and helps to control some soil-borne pests and diseases.

(a)(ii) Four common liming materials:

• Quicklime (calcium oxide, CaO)
• Slaked or hydrated lime (calcium hydroxide, Ca(OH)₂)
• Ground limestone (calcium carbonate, CaCO₃)
• Dolomitic limestone (CaMg(CO₃)₂); wood ash and marl are also used.

(b)(i) Three examples of nitrogenous fertilizer:

• Urea
• Ammonium sulphate
• Ammonium nitrate (calcium ammonium nitrate and sodium nitrate are also acceptable)

(b)(ii) Three examples of a phosphorus fertilizer:

• Single superphosphate
• Triple superphosphate
• Rock phosphate (bone meal and basic slag are also acceptable)