(a)List three edaphic factor that influence crop growth. [3marks] (b) Explain the following terms as used in soil and water conservation: (i)gravitational w...
Question 1 Report
(a)List three edaphic factor that influence crop growth. [3marks]
(b) Explain the following terms as used in soil and water conservation: (i)gravitational water(ii)hygroscopic water [4marks]
(c) State two deficiency symptoms of each of the following nutrient elements in crops:(i)nitrogen; (ii) phosphorus; (iii)potassium [6marks]
(d) State three benefits derived from draining farmlands. [3marks]
Answer Details
(a) Three edaphic factors that influence crop growth
- Soil texture.
- Soil structure.
- Soil pH (soil reaction) and nutrient/organic-matter content.
(b) Explanation of terms
- (i) Gravitational water: This is the water that drains freely through the soil under the force of gravity after the soil has been saturated. It moves down to the water table and is not available for plant use.
- (ii) Hygroscopic water: This is the very thin film of water held tightly around soil particles by adhesive forces. It is held so firmly that it is not available for plant use.
(c) Two deficiency symptoms of each nutrient element
(i) Nitrogen:
- Stunted growth.
- Yellowing (chlorosis) of leaves, starting with the older leaves.
(ii) Phosphorus:
- Stunted growth with delayed maturity.
- Purple/reddish colouration of leaves and stems, and poor root development.
(iii) Potassium:
- Scorching/browning of leaf margins (marginal necrosis).
- Weak stems that lodge easily.
(d) Three benefits derived from draining farmlands
- It removes excess water and prevents waterlogging.
- It improves soil aeration and warms the soil.
- It promotes root development and improves the workability of the soil.
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