The sustainability of agricultural food commodity production in the humid tropics of Central and Western Africa
1992
Jutzi, S.C. (Kassel Gesamthochschule, Witzenhausen (Germany). Fachbereich Internationale Agrarwirtschaft. Fachgebiet Feldkulturen der Tropen und Subtropen)
The African humid-tropical rainforest is converted into agricultural land far more rapidly than Latinamerican or Asian rainforest. In Africa this process is primarily propelled by smallholder subsistence agriculture. The sustainability of the methods conventionally utilized in this process (shifting, slash-and-burn, swidden cultivation) is threatened by the shortening of fallow periods due to increasing rural population pressure. Similarly, continous, monoculture-based field crop production on humid-tropical soils with massive external input is linked with considerable ecological risks and constraints. Humid-tropical soils are strongly weathered and therefore present low inherent fertility, low nutrient and water retention capacity, and unbalanced ion load in the exchange complex. Continously high ambient temperatures, high rainfall amounts and high rainfall intensities accelerate the process of soil deterioration and soil loss. These soils require maximum biological protection for their sustainable utilization. In analogy to the conditions prevailing within the rainforest which can provide such soil protection, the sustainability of the soil resource in field crop production is intimately linked with its association with tree vegetation. Only genetically diverse, complex (alley farming), integrated tree-(legumes), crop- and animal-based land use with low external, but nomally high internal input in the sense of integrated agro-sylvo-pastoral systems are in a position to sustainably satisfy the high requirements of the humid-tropical ecology.
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