Theory question 103
Forestry and Wildlife(a) Explain each of the following agro-forestry practices in West Africa. (i) alley cropping; (ii) ley farming; (iii) taungya system
(b) Give five reasons why agro-forestry is practised by farmers in West Africa.
(c)(i) Describe the water cycle. (ii) List two forms of water in the soil.
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(a)(i) Alley cropping: arable crops are grown in alleys between rows of (usually leguminous) trees or shrubs such as Leucaena and Gliricidia, which are pruned regularly and the prunings used as mulch/green manure.
(ii) Ley farming: land is used for arable crops for some years and then put under grass/legume pasture for livestock for some years, in rotation.
(iii) Taungya system: farmers grow food crops between young forest trees during the early years of forest establishment, until the tree canopy closes.
(b) Any five: improves soil fertility (nitrogen, leaf litter); controls erosion; provides fuelwood, timber and fodder; diversifies income; provides shade and windbreaks; controls weeds; makes full use of land; conserves biodiversity and moisture.
(c)(i) Water from seas, rivers, soil and plants evaporates (and transpires) into water vapour; the vapour rises, cools and condenses into clouds; it falls back as rain (precipitation); some runs off into rivers and seas, some infiltrates the soil and becomes groundwater, and the cycle repeats.
(ii) Any two: gravitational water; capillary water; hygroscopic water.
Name each stage of the cycle in order.