Agricultural Science

Topic: Environmental Factors Affecting Agricultural Production

Contents

• Meaning And Elements/Factors Of Climate
• How Climate Determines The Type Of Crops And Animals Found In Nigeria
• Environmental Factors Affecting Agricultural Production

Objectives

At the end of this article, readers should be able to:

1. Define climate.
2. State the importance of climate in agriculture.
3. Discuss some elements of climate and their effects in agriculture.
4. State the environmental factors that affect agricultural productivity.

Meaning And Elements/Factors Of Climate

Definition: Climate is defined as the average weather condition of a place, measured over a long period of time (over 35 years).

Factors Of Climate

Factors or elements of climate include:

1. Rainfall
2. Temperature
3. Wind
4. Relative Humidity
5. Pressure
6. Light
7. Radiant energy.

Importance Of Climate In Agriculture

1. Climate affects the duration of cropping season.

2. It determines the yield of Crops.

3. Climate limits the types of crop to be grown in an area.

4. It also affects vegetation distribution in an area.

5. It affects the incidence of pests.

6. It affects the incidence of diseases.

7. Climate determines the yield or productivity of animals.

8. Climate limits the type of livestock to be reared in an area.

9. It also affects the type of Soil formation in an area.

How Climate Determines The Type Of Crops And Animals Found In Nigeria

Essential factors of climate which determine the types of crops and animals founf in Nigeria are rainfall and temperature.

Rainfall

1. Rainfall is defined as the amount and distribution of water precipitated within a given time, in a given area.

2. It is brought about by the South West Trade winds which blow from Atlantic Ocean.

3. As the wind blows from the Ocean to inland, it drops the water it is carrying.

4. As a result of this, the coastal areas receive more rainfall per annum than the rest of the religion.

5. As the moisture-laden wind moves further inland, the amount of rainfall decreases.

6. By the time this wind gets to the northern part of the country, there is little or no moisture left in it.

7. In the northern areas, less rainfall is experienced per year.

8. In the coastal areas, rainy season ranges from eight months to all the year round while in the north, rainy season lasts for only three to four months.

9. This moisture regime affects crops and livestock distribution.

10. In the coastal areas, which are the more humid southern part, crops which adapt to heavy rainfall are predominant, e.g rice, maize, fruit, cocoa, forest trees, yams and banana.

11. Much animal rearing does not take place in heavy rainfall areas because of high humidity and tse tse fly infestation.

12. Consequently, only animals such as dwarf sheep, goat, poultry, Muturu and N’dama cattle which are resistant to trypanosomiasis can be reared.

13. In the northern parts, with little rainfall, crops which are drought resistant like guinea corn, millet, cowpea, groundnut, cotton and beniseed are grown.

14. These crops normally complete their life cycles within three to four months of rainfall. This area is the animal-rearing zone because of few or no tse-tse fly.

15. Animals like donkeys, cattle, sheep, goats, camels and horses are reared here successfully because of sufficient grassland for grazing them.

Temperature

1. Temperature is defined as a measure of the heat energy which a body contains or the degree of hotness and coldness of a place at a point in time.

2. There is variance of temperature from the coastal areas to the extreme north.

3. During the dry season, temperature is extremely high in the north but not as high in the coastal areas.

4. Though many farming activities do not take place in dry season, the crops found in the north are high temperature-loving plants, like tobacco.

5. The average minimum temperature varies from 22oC in the coastal areas, e.g. Calabar, during the coldest month of the year to about 13oC in the northern areas, e.g., Nguru, during the coldest harmattan season.

6. Owing to this coldness, wheat can be successfully grown in the north under irrigation, while it cannot be grown in the coastal areas.

7. Animals found in the northern areas are also well-adapted to withstand the severe heat of the sun.

Environmental Factors Affecting Agricultural Production

Environmental factors affecting agricultural production are grouped into three major classes. These are:

1. Climatic factors
2. Biotic factors
3. Edaphic factors

Climatic Factors Affecting Agricultural Production

1. Rainfall

Definition: Rainfall is defined as the release of excess condensed water vapour in the atmosphere into the earth.

1. It determines the distribution of crops and animals.

2. It is necessary for seed germination.

3. Insufficient rainfall cause crop failure and poor yield.

4. The seasons also determine when crops would be planted.

5. It determines the seasons in Nigeria, i.e, rainy and dry seasons.

6. Excessive rainfall leads to leaching of nutrients and cause Erosion.

Ways In Which High Rainfall Affects Agricultural Production

1. High rainfall prolongs the cropping season.

2. It increases the problem of plant diseases.

3. It determines the type of crop to be grown.

4. It increases the incidence of erosion or flooding.

5. It encourages thick forestation, thus increasing the incidence of pest e. Tse-tse flies infestation.

6. It encourages growth of disease causing organisms (pathogens).

7. It increases leaching of plant nutrients or soil acidity.

8. It cause water logging in clay soil.

9. It encourages faster or rapid growth of weeds.

2. Drought

This is defined as lack of or insufficient rainfall in an area.

Effects Of Drought On Plant Growth And Development:

1. Delay in flowering/reduction in flowers/flower abortion.

2. Poor crop establishment.

3. It leads to a reduction in leaf area.

4. There is a reduction in cell size and inter-cellular volume.

5. Several physiological processes may decrease due to the dehydration of protoplasm.

6. Water stress produces important changes in carbohydrate and nitrogen metabolism of plants.

7. Difficulty in pegging, especially in groundnut.

8. Possible death of plants/crop failure.

9. There is reduction in yield.

10. Wilting.

3. Temperature

Definition: Temperature is defined as the degree of hotness or coldness of a place.

1. Temperature is necessary for germination of seeds.

2. It also affects the distribution of crops and animals.

3. Too hot or too cold temperature does not favour plants and animals growth.

4. Unfavourable temperature may result in seed dormancy.

5. High temperature reduces the performance of livestock.

6. It affects the wilting of field crops, ripening and maturity of crops.

4. Wind

Definition: Wind is defined as air in motion.

1. High wind velocity may cause wind erosion.

2. It aids seed and fruit dispersal.

3. It can aid pollination and spread of diseases.

4. It helps in the distribution of rainfall and changes in seasons, e.g. Rainy and dry seasons.

5. High wind velocity causes damage to crops e.g lodging.

6. It determines seasons in Nigeria. For example, South West Trade wind brings rain while North East Trade winds brings harmattan or dry season.

5. Sunlight/Sunshine

Definition: Sunshine is the amount of heat and the period the sun’s rays are received at a place.

1. Sunlight is necessary for photosynthesis.

2. It affects evapo-transpiration.

3. It affects the productivity of crops due to length of day, i.e, photoperiodism. In other words, light divides plants into three photo periods:

a. Long Day Plants: These plants require longer day light of between 13 – 15 hours of sunlight, e.g, millet, sorghum (guinea corn).

b. Short Day Plants: These plants require shorter day light period of between 8 – 10 hours of sunlight, e.g., cocoa, kola and oil palm.

c. Day-neutral Plants: These plants require equal period of day and night; that is, about 12 hours of sunlight and 12 hours of darkness, e.g. Tomato.

4. Light affects the rising and roosting of animals.

5. It affects the rate of production.

6. It determines the productivity of cultivated crops.

6. Relative Humidity

Definition: Relative humidity is defined as the amount of moisture in the atmosphere.

1. It results in the formation of rain.

2. It affects the performance of crops and animals.

3. High humidity in poultry houses cause mouldness of feed and litters.

4. Low humidity causes aridity or dryness.

5. High relative humidity favours the growth of disease pathogens.

6. Relative humidity determines the type of pests prevalent in an area.

7. Solar Radiation

Definition: Solar radiation is the amount of heat or sun rays radiated to the atmosphere.

1. High intensity of radiation cause heat stress in animals, and this reduces growth, production and reproduction.

2. Solar radiation assists photosynthesis in crops.

3. Solar radiation is a source of farm power.

4. Solar radiation assists in drying of crops.

5. It increases the cost of production because shades has to be provided to protect animals and some crops from direct rays of the sun.

Biotic Factors Affecting Agricultural Production

1. Soil Organisms

1. These include bacteria, fungi, earthworm, rodent and termite.

2. Some, like bacteria and fungi, can cause diseases.

3. Some aid aeration of soil, percolation and fertility.

4. Some help in the decomposition of plant materials to form humus.

5. Some reduce the quality and quantity of crops, e.g, potato and yam.

2. Pests

1. These include insects, rodents, birds and some mammals.

2. They reduce the yield of crops and animals.

3. They also reduce the quality of crops and animals.

4. The cost of their control increases the cost of production.

5. Some are vectors or carriers of diseases.

3. Parasites

1. They include ticks, liver flukes, tapeworms, dodder, mistletoe and lice.

2. Some transmit diseases.

3. They reduce the quantity or yield of produce.

4. They also reduce the quality of produce.

5. They reduces production capacity of livestock or crops.

4. Diseases

1. They may be diseases caused by viruses, bacteria, fungi, protozoa, etc.

2. They cause reduction in yield of crops and animals.

3. They can cause the loss or death of plants and animals.

4. The cost of control increases the cost of production.

5. The cause reduction in farmer’s income.

5. Weeds

1. They compete with crops for space, water, nutrients and sunlight.

2. Some weeds can harbour diseases and pests.

3. They reduce the yield of crops.

4. Weed control increases the cost of production.

5. Weed cause poor growth of crops.

6. Predators

1. These are birds, rodents and praying mantis.

2. Some are beneficial in agricultural production.

3. Some are used to control some harmful pests of crops and animals.

4. Some feed on farm animals. For example, hawks feed on chicks.

7. Human Activities

Human activities include the influence of man on the production of plants and animals.

1. His activities may improve the fertility of the soil if he uses fertilizers and manure.

2. There could be increase in yield if he practises crop rotation.

3. There could be increase in yield if he control pests and diseases,

4. Increase in yield or production can also be enhanced if he gets rid of weeds from his farm.

5. Continuous cultivation bush burning and inability to control erosion can lead to lower agricultural output.

Edaphic Factors Affecting Agricultural Production

1. Soil pH

1. It affects the growth of plants.

2. It also affects the availability of soil nutrients to plants.

3. It affects the presence of soil micro-organisms.

4. It causes toxicity to plants and animals in the soil.

2. Soil Texture

1. It determines the type of soil in an area.

2. It determines the level of soil fertility.

3. It determines the type of crops to be grown.

4. It affects the level of leaching and erosion.

3. Soil Structure

1. It determines the fertility of the soil.

2. It determines the water-retaining capacity of soil.

3. It determines the level of soil organisms.

4. It determines the level of soil aeration and percolation.

4. Topography

1. Topography refers to the shape of the land in relation to the underlying rocks of the earth’s surface.

2. Steep and gentle slopes give rise to soil erosion.

3. Steep and gentle slopes may also aid the weathering of rocks.

4. Even or flat slopes can lead to accumulation of soil.

5. Even or flat slopes can be better sites for intensive farming.

5. Soil Fertility

1. Fertile soil aids the production of food and cash crops.

2. Fertile soil leads to the production of forage crops and plants for grazing.

3. It minimizes the use of fertilizers and manures.

4. It leads to multiplication of beneficial soil organisms.

5. Fertile soil generally leads to reduction in cost of production.

6. Soil Types

1. Soil types include sandy, clay and loamy soil.

2. Loamy soil is rich in soil nutrients, hence it is the best soil for agriculture.

3. Sandy soil does not contain enough nutrients, hence it cannot support crop growth.

4. Sandy soil encourages water-logging and erosion but prevents leaching of plant nutrients.

7. Soil Erosion

Definition: Soil erosion is defined as the wearing away of soil by means of natural agents such as water, ice or glacier, wind and animals.

Erosion takes place for a long time and it is greatly influenced by the following factors:

1. Climate
2. Soil Properties
3. Vegetation
4. Human activities
5. Topography

Agent OF Soil Erosion: Agents of soil erosion are mainly water and wind.

1. Water: Rainwater tends to run off the surface of the soil in deforested or over-grazed areas, thereby removing the top soil. Run-off is the rainwater which does not sink into the soil but flows away over the surface of the soil into streams, rivers or oceans.

2. Wind: Wind is capable of moving large quantity of soil and sand. The faster the wind moves, the more it can carry. Wind-caused erosion occurs in dry areas where the soil is bare and loose.

Types Of Soil Erosion

There are four major types of erosion. These are:

1. Splash Erosion: Splash erosion is the removal of top soil from as small area due to the forceful fall of rain.

2. Rill Erosion: Rill erosion occurs when raindrops falling on the soil surface cause the gradual removal of soil particles in suspension along narrow tracks or channels either already existing or caused by the rainwater itself.

3. Sheet Erosion: When raindrops cause particles to block soil pores against percolation, floods follow.

4. Gully Erosion: Gully erosion occurs when rain water does not all sink into the soil and part of it runs off over the soil surface, removing soil particles along its way.

Prevention And Control Of Soil Erosion And Soil Conservation Practices That Can Be Used To Control Erosion On A Gentle Slope:

1. Terracing.
2. Contour Ploughing
3. Ridging Across The Slope.
4. Construction of drainage channels.
5. Cover cropping/ Afforestation/ High density planting.
6. Strip cropping
7. Mulching

How Each Practice Can Be Used To Conserve The Soil

1. Terracing

1. It is a practice in which the slope is broken into series of steps or platforms.

2. Each platform or step is constructed along a contour so that each of them is on uniform height, but different from those above or below it.

3. It is done to reduce the length and gradient of slope and hence reduce the speed of run-off.

2. Contour Ploughing

1. The slope is first surveyed to locate contour points.

2. Ploughing is now done along the contours joining all areas along each contour.

3. These contours are running across the slope of the land.

4. Plants are established along the contours and not across.

3. Ridging Across The Slope

1. Flood water will normally run down along the slope of a land.

2. Ridges constructed should be across the slope to block the run-off water.

3. Such ridges will also help to trap the water into small reservoirs which will sink into the soil.

4. It can be practised by every farmer without much technical know-how.

4. Construction Of Drainages

1. Drainages are means of getting rid of excess water in the field.

2. Many types of drainages are available. They may be open channels or underground channels.

3. Pipes are laid along the slope to carry the water straight down into reservoirs below, thus preventing soil erosion or loss.

5. Cover Cropping/Afforestation/High density planting

1. The principle is not to allow the surface to be exposed to agents of erosion e.g wind, water.

2. The slope is planted with cover crops or other crops to trap or retard any run-off water.

3. Their leaves decay and enhance soil fertility, thereby encouraging more growth of other species.

6. Strip Cropping

1. Planting of crops in rows along the contour interspersed by rows of uncultivated area or fallow, to retard water run-off across the slope.

2. It also entails planting of different crops with different growth characteristics in alternate rows along the contour and across the slope to check run-off.

7. Mulching

1. Mulching is the act of covering soil surface with such materials as dry grassed, crop residues and polyethylene sheets.

2. It reduces the impact of rain drops on soil.

3. It reduces the spend of run-off.

4. Decayed mulch improves soil structure and so helps check soil erosion.

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