In today’s class, we will discuss the environmental factors affecting agricultural production. 

CONTENT:

Environmental factors affecting agricultural production can be grouped into:
Climate factors
Biotic factors
Edaphic factors.

Climate: This can be defined as the average weather condition of a place measured over a long period.

  Factors of climate

It includes rainfall, relative humidity, temperature, light, wind, and pressure.
Each of the factors influences agriculture. This is shown by the distribution of vegetation and crops in the climatic zones. The result is that when the soil conditions are favourable, thick evergreen forest develops.

A.) Rainfall:
It is defined as the amount and distribution of water precipitation within a given time in a given area.

Rainfall distribution and pattern

West Africa is known for its high temperatures throughout the year. It is brought about by the southwest monsoon trade wind blowing from the Atlantic Ocean.

The wind blowing from the ocean to the inland drops some water. A narrow part of the coast has the wind blowing from the ocean to the inland drops some water. A narrow part of the coast has rainfall throughout the year, against the rest of the region. As we move from the coast, the amount of rainfall decreases. By the time the wind gets to the northern part of the country, there is little or no moisture left in it. Here, less rainfall is experienced per year. In the coastal area, the rainy
season ranges from 8 months to all year round, while in the north, the rainy season lasts only 3 to 4 months..

The moisture required affects crop and livestock production. In the coastal areas, more in the southern parts, crops adapted to heavy rainfall predominantly trees, yam, maize, rice, fruit, banana, etc. Much animal rearing does not take place here due to the high humidity rate which exposes the animals to tsetse fly infection.

Only animals that can resist the attack of trypanosomiasis can be seen in this area. Examples are N’ dama and Muturu breeds of cattle, dwarf sheep and goat, and poultry. Those crops that can thrive well in the northern part with little rainfall or resistance to drought are guinea corn, millet, groundnut, cowpeas, cotton, etc.

Importance/effect of rainfall

• It determines the distribution of crops and animals.
• It helps to dissolve nutrients in the soil, making it available for plant use
• It is necessary for seed germination.
• Excessive rainfall leads to leaching of nutrients and causes soil erosion.
• It determines the type of vegetation of an area.

Insufficient rainfall causes crop failure and poor yield.

B.) Temperature:
It is defined as a measure of the heat energy that a body contains or the degree of hotness or coolness of a place, at a point in time. Temperature varies from the coastal areas to the extreme north. In the dry season, the temperature is not high in the coastal area as against the extremely high north.

Importance/effects of temperature

• It affects the distribution of crops and animals.
• Necessary for the germination of the seed.
• The unfavourable temperature may result in seed dormancy
• High temperature may cause premature dropping of fruits and sudden death of livestock in heat stress.
• High temperature reduces the performance of livestock.

C.) Sunlight:

Importance/influence

• It is necessary for photosynthesis.
• It affects the rate of production in poultry.
• It affects evapotranspiration.

D.) Wind:

Influence/importance

•  High winds may cause wind erosion.
• It aids seed and fruit dispersal
• It can aid pollination and the spread of disease.
• It helps in the distribution of rainfall and changes in seasons e.g., rainy and dry seasons
• High wind velocity causes damage to crops.

 E.) Relative humidity:

Influence

• It results in the formation of rain
• It affects the performance of crops and animals
• High humidity in poultry causes moldiness of feed and litter.
• Low humidity leads to heat stress in animals.

Relative humidity determines the type of pests prevalent in an area. High relative humidity forms the regrowth of disease pathogens.

 Biotic factors or biological factors affecting crop and animal production

1. Predators: These are living organisms that prey on or feed on other organisms. Examples are birds, rodents, insects, etc. Some are beneficial and some are destructive. Some control harmful pests of crops and animals, others feed on other animals, e.g., hawk,s etc.

2. Parasites (Parasitism): A parasite is an organism that lives on or in another living organism known as the host. It obtains its food from the body of its living host. Often, a parasite harms its host by causing diseases or death.

Types of parasites

•  Endoparasite: These are parasites that live inside or within the body of other animals. e.g.liver fluke, tapeworm, roundworm, or Ascaris.
•  Ectoparasite: Parasites that live outside or on the host. Examples ticks, lice, mites, insect bugs,fleas, etc.
• Soil organism: Soil organisms can be classified into a microorganisms or macroorganisms.

Microorganisms are bacteria, virus,es etc., while macro-organisms are rodents, termites, centipedes etc. Some, like bacteria and fungi, can cause disease, some aid aeration in soil, hence improving soil fertility. Some, like root nodule bacteria, can fix nutrients directly to the plant and soil. Some help in the decomposition of plant and animal material to form humus.

 3. Pests: These organisms cause damage or destroy crops either in the field or in stores. They include insects, rodents, birds, and some animals e.g,. monkeys. They reduce the yield of crops and animals, thereby reducing the farmer’s income. Some are vectors or carriers of diseases.

The cost of their control increases the cost of production.

a.  Diseases: The disease is a situation in plants or animals in which there is a deviation of the plant or animal from a normal state of health. The disease can be caused by pathogens which are a viruses, bacteria, fungi, protozoa, etc. They cause a reduction in the yield of crops and animals. They can cause the loss or death of plants and animals. The cost of control increases the cost of productio,n which affects the income of the farmers.

b,. Mutualism (Symbiosis): In mutualism, two organisms live together for the mutual benefit of each other. Termites and the protozoa living in their guts are mutualistic. The protozoa receive protection from termites; it helps in the breakdown of food in termites. The protozoa helps them to digest it.

c.. Weeds: They compete with crops for space, water, nutrients, and sunlight. Some may harbour diseases and pests. They reduce the yield of crops. Control increases the cost of production

Edaphic factors or physical factors

1. Soil pH: This is the degree of acidity or alkalinity of a soil.

•  It affects the growth of the plant.
• It affects the availability of soil nutrients to plants.
• It affects the presence of soil microorganisms

2. Soil texture: This is the measure of fineness or coarseness of soil samples.
It determines the type of soil in an area. It determines the level of soil fertility.
It determines the type of crops to be grown. It affects the level of leaching and erosion of the soil.

3. Soil structure: This is the physical appearance of the soil according to the way individual particles are packed or arranged.

It determines the fertility of the soil.

It determines the water-retaining capacity of the soil

It determines the level of aeration.

It determines the level of microorganisms

General evaluation

1. What is soil structure?

2. Define soil texture.

3. What is soil pH?

4. State three features of soil texture

5. List out five soil organisms

Theory

1) Discuss briefly five biotic factors that affect crops and animals.

2) State three edaphic factors affecting crops and animals.

In our next class, we discuss Classification of Crops: Based on Life Cycle, Morphology and Uses. 

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