Theory question 104
Land Preparation and Cultural Practices(a)(i) Define the term soil tillage. (ii) Distinguish between primary tillage and secondary tillage.
(b) Outline three roles of each of the following soil management practices: (i) green manuring; (ii) mulching.
(c) Give six reasons for carrying out irrigation in crop production.
Show the model answer
(a)(i) Tillage is the working (loosening, turning) of the soil with tools or machines to make it suitable for crop growth.
(ii) Primary tillage is the first, deep working of the soil that breaks and turns it (ploughing); secondary tillage follows it and breaks clods into a fine tilth and levels or ridges the soil (harrowing, ridging).
(b)(i) Green manuring: adds organic matter/humus; adds nutrients, especially nitrogen from legumes; improves soil structure and water holding; increases soil organisms; protects soil from erosion while growing.
(ii) Mulching: conserves soil moisture; suppresses weeds; reduces erosion; moderates soil temperature; adds organic matter when it rots.
(c) Any six: supplies water during the dry season/drought; allows all-year cropping; supplements irregular rainfall; makes dry land cultivable; softens soil for planting; can carry fertilizers (fertigation); controls soil temperature/frost; leaches excess salts; increases yield.
Show the difference in (a)(ii) by when and how each is done.