Theory question 102
Soil Properties(a) Explain each of the following terms as used in agricultural ecology: (i) soil texture; (ii) soil structure; (iii) soil profile.
(b)(i) State three advantages of grafting. (ii) Name two tree crops that could be propagated by grafting.
(c) List three cultural practices that could be used to replenish nutrients in the soil.
(d) Give four measures that farmers could adopt to control pests in grain stores.
Show the model answer
(a)(i) Soil texture: the relative proportions of sand, silt and clay particles in a soil (coarseness or fineness).
(ii) Soil structure: the way soil particles are grouped or arranged into aggregates (crumbs, blocks, plates).
(iii) Soil profile: a vertical section of soil from the surface down to the parent rock, showing the horizons.
(b)(i) Any three: combines good qualities of stock and scion; early fruiting; plants true to type; disease/drought-resistant rootstock; propagates plants that do not root easily.
(ii) Any two: citrus (orange); mango; avocado; cocoa; rubber; cashew.
(c) Any three: crop rotation with legumes; bush fallowing; green manuring; cover cropping; mulching; organic manuring/composting; liming.
(d) Any four: clean and fumigate the store before storage; dry grains properly; use storage insecticides/fumigants; airtight containers; rat guards/traps; inspect regularly and remove infested grain; use hermetic bags/silos.
Define each soil term in one sentence.