Question

Difficulty: HardAgricultural Systems and Practices in Africa

In the nutrient-poor, highly leached soils of the Miombo woodlands in Central and Southern Africa, local farmers practice a specialized variant of shifting cultivation known as the *Chitemene* system. What is the primary ecological mechanism by which this agricultural practice temporarily restores soil fertility for crop production?

  1. Concentrating and burning tree branches lopped from a wide surrounding woodland area to create a nutrient-rich ash bed that reduces soil acidityAnswer
  2. B
    Deep sub-soil ploughing to expose un-weathered mineral parent rock to intense tropical weathering in arid northern savanna belts
  3. C
    Controlled seasonal river flooding that deposits rich alluvial silt onto low-lying floodplain terraces during annual high-discharge flows
  4. D
    Application of synthetic nitrogenous fertilizers combined with continuous leguminous crop cover to eliminate the need for fallow periods

Answer

The primary ecological mechanism of the Chitemene system is concentrating tree branches from a wide area into a central plot and burning them, which creates a nutrient-rich ash bed that neutralizes soil acidity.
The Chitemene system is a distinctive indigenous agricultural practice in Central Africa (notably Zambia). Because the soils of the Miombo woodlands are heavily leached and acidic, farmers lop branches from surrounding trees across a wide perimeter, haul them into a central field, and burn them. The ash layer provides a concentrated boost of mineral nutrients and temporarily neutralizes soil acidity, allowing crop growth for a few seasons before the plot must be left fallow.

Step-by-Step Solution

1
Identify the geographical region and system in question
The Chitemene system is a traditional shifting cultivation method practiced in the Miombo woodland zone of Central/Southern Africa (e.g., Zambia).
Establishing the system's operational context clarifies its environmental constraints.
2
Analyze the soil condition and agricultural adaptation
Miombo soils are highly leached, acidic, and nutrient-poor oxisols/ultisols.
Understanding the soil limitation explains why simple clearing is insufficient.
3
Determine the specific technique used to overcome soil infertility
Farmers cut (lop) branches from an area about 5–8 times larger than the planted plot, stack them in the center, and burn them.
Branch lopping concentrates the biomass nutrients into a smaller burn area.
4
Evaluate the chemical and physical effect of burning on the soil
The ash deposit releases essential minerals (potassium, calcium, magnesium) and raises the soil pH (reduces acidity), creating a fertile seedbed for crops like finger millet.
This confirms the primary ecological mechanism responsible for temporary fertility.

Key Concept

Chitemene System and Soil Fertility Restoration in African Shifting Cultivation
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