Theory question 103
Agricultural Ecology(a) Discuss three effects of each of the following factors on crop production: (i) water; (ii) air; (iii) soil microbes.
(b) List three edaphic and four climatic factors that affect crop productivity.
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(a)(i) Water: needed for germination and photosynthesis; solvent and transport of nutrients; keeps cells turgid and cools by transpiration; too much causes waterlogging, too little causes wilting
(ii) Air: oxygen for root and seed respiration; carbon dioxide for photosynthesis; nitrogen fixed by bacteria; wind helps pollination and seed dispersal but causes lodging
(iii) Soil microbes: decompose organic matter releasing nutrients; fix nitrogen; improve soil structure; some cause plant diseases
(b) Edaphic (any three): soil pH; texture; structure; fertility; organic matter; drainage; topography. Climatic (any four): rainfall; temperature; sunlight; relative humidity; wind
Three effects each for water, air and microbes.