Discuss the Physical Factors that Control Agricultural Distribution

The physical factors also known as geographical, natural or environmental factors
include climate, topography, and soil.

(a) Climate: Several climatic factors affect the type and distribution of agriculture in
East Africa, but the most significant are rainfall and temperature.

- Rainfall is the single most dominant weather element influencing the intensity and
location of farming systems. Areas that receive high rainfall (over 1000mm) and
those that have low evaporation rates are intensively cultivated. In such places the
received rainfall has a high effectiveness and reliability. Rainfall effectiveness is the actual received in a given place, minus the total possible evaporation. Rainfall
is said to be reliable if its deviation from the mean (average) figure does not
exceed 20%. A viability of more than 20% implies a great risk to farming and
rain-fed agriculture in such circumstances cannot be practiced successfully.

- Temperature is very critical for plant growth because each plant or crop requires a
particular minimum growing temperature. Warm temperatures (16-22^oc) are
better suited to a variety of agricultural practices than extremely high and cold
temperatures (25^0c) increase evapo-transpiration rates thus decreasing moisture
available for crop production; and when coupled with high humidity, they become
favourable to a variety of insect pests and a higher incidence of plant pathogens.
Very few crops (dates) and animals (camel) will survive in regions of extreme
temperatures. On the other hand, too low temperatures (10^oc) discourage the
growth of many crop varieties, cause delays in the maturity of cereal crops such
as maize and sorghum and may also lead to crop losses (Awour and Ogola, 1997).
Areas of extremely low of high temperature are extensively utilized.

(b) Topography’s characteristics influence the type and intensity of agriculture in
Africa. These include:

- At high altitudes, decreased atmospheric pressure causes big problems, inhibiting
human settlements and limiting agricultural activities that can be conducted there.
Vegetation growth is restricted and crops take long to mature. Soils too take long
to mature as there are fewer mixing agents; humus content takes longer to break
down, and leaching is more likely to occur.

Moderate to high altitude lands are intensively used. Dairy farming is
an important agricultural activity practiced in such places. Crops like tea and
coffee grow best on well-drained hilly slopes and at altitudes of up-to 2000m
above the sea level. This explains why the slopes of Mt. Kenya and Mt. Meru are
intensively cultivated.

Lowlands especially those receiving effective and reliable rainfall are some of the
most intensively cultivated parts of East Africa world. The level-ness of the
ground eases cultivation and makes the use of machinery possible. But lowlands
that do not receive adequate rainfall are usually extensively used.

- Slope also affects agricultural land use. Steep slopes are in most cases not used
for agriculture, except in the cases where population pressure has forced farmers
to encroach on such land. These are fragile ecosystems. It is true that all soils are
prone to erosion but it is also true that erosion is greater on steep slopes than on
gentle slopes. Such soils can only become productive if appropriate management
strategies are applied. This is because the soils are poorly developed, are thin and
hence very vulnerable to erosion. In addition steep slopes pose a serious limitation
to the use of machinery.

Gently and moderately sloping lands especially the windward sides are
intensively used. This is particularly true where adequate rainfall is received and
whether means of transport are developed.

(c) Soils (edaphic factor) constitute the physical base for any agricultural activity.
Soils endowed with a proper combination of texture, salts and humus tend to be very
productive, give high yields and are usually intensively cultivated. As soils are so varied
in their physical and chemical composition, their suitability for the cultivation of crops
varies tremendously. The characteristics of a soil that determine its usefulness include:

- Soil texture: the texture of a soil influences the ease of cultivation, root
penetration, aeration, and absorption. For example, clay soils retain a lot of
moisture, are heavy to work and are best suited to wet crops like rice. Sandy soils
lack coherence, but are well aerated, and easy to work and are best suited to crops
like barley, dates, cotton, wheat, maize and pulses. Loamy soils are the most ideal
for agriculture. They have sufficient: clay 20 per cent, which helps in moisture
and nutrients retention; sand, 40per cent which prevents water logging, allows for
adequate aeration and makes them easy to cultivate and silt 40 per cent which acts
as an adhesive, holding the sand and clay together. As such they accommodate a
wide range of crops and are intensively cultivated. Loam soils are also least
susceptible to soil erosion.
- Soil composition: Apart from their mineral content (influenced by parent rock)
soils contain organic matter derived from the decomposition of plants and
animals. The higher the organic matter in a soil, the more fertile it is; the higher
its resistance to erosion and the more intensively it is utilized.

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Titany answered the question on January 18, 2022 at 05:35