Effect of fire on soil, rice, weeds and forest regrowth in a rain forest zone (Coˆte d'Ivoire)

摘要: Abstract In south-western Coˆte d'Ivoire mature forest is felled and burned one crop of upland rice grown. Forest then allowed to regenerate for 15 or more years before being cropped again. Soils are very gravely, clayey, acid, thoroughly leached chemically poor. Forest, soil, rice, weeds regrowth were studied in the fields local farmers permanent plots during 2–5 years. The (16) covered all currently cultivated soil types types. Burning leads an instant mineralisation organic matter ashes produce a marked decrease acidity (before burning pH 4.4–5.2, after 5.4–6.2). nutrient availability further stimulated by reduction Al activity solution. Fire decisive factor cultivation: slightly burnt unburnt areas wholly unproductive. thrives on nutrients contained ash rather than mineral soil: nature relatively little importance, as long large quantities biomass burnt. A fire normal intensity destroys enough buried seeds vegetative parts plants avoid weed stress, yet allows survival sufficient number crop. Excessive kills sprouts seeds. Regeneration comes from dispersed into field fire, mainly grasses forbs. Grassy shrub land thickets thus formed.