Theory question 104
Agricultural Ecology(a) With the aid of an annotated diagram only, illustrate the water cycle.
(b) State three forms in which water exists in the soil.
(c) List five importance of water to crops.
Show the model answer
(a) Annotated diagram: evaporation from seas, rivers and soil; transpiration from plants; condensation into clouds; precipitation (rain); infiltration and percolation into soil and ground water; run-off back to rivers and sea
(b) Gravitational water; capillary water; hygroscopic water (also water vapour)
(c) Any five: raw material for photosynthesis; solvent and carrier of nutrients; keeps cells turgid/supports soft plants; cools the plant by transpiration; needed for seed germination; part of protoplasm; aids enzyme activity and translocation
The diagram must show evaporation, condensation, precipitation and run-off with arrows.