ENVIRONMENTAL FACTORS AFFECTING AGRICULTURAL PRODUCTION
Subject:
Agricultural Science
Class:
Senior Secondary School Year 1
SSS 1
Term:
Second Term / 2nd Term
Week:
Week 3
Topic
ENVIRONMENTAL FACTORS AFFECTING AGRICULTURAL PRODUCTION
Previous Knowledge: The pupils have previous knowledge of
AGRO-ALLIED INDUSTRIES AND RELATIONSHIP BETWEEN AGRICULTURE AND INDUSTRY
that was taught in their previous lesson.
Behavioural Objectives : At the end of the lesson, learners will be able to
- Define Climate
- List climatic Factors that affect climate formation
- Explain Biotic Factors
- List edaphic Factors that affect soil formation
Instructional Materials
- Wall charts
- Online Resource
- Textbooks
- Laptop
- Flash cards
Methods of Teaching
- Role modelling
- Questions and Answers
- Explanation
- Discussion
- Recitation
- Imitation
- Story Telling
- Dramatization
Content:
Agricultural activities such as crop and livestock production are affected by several environmental factors.
These environmental factors determine and influence the distribution of crops and livestock as well as the performance and productivity of crops and livestock.
Climatic Factors
Climate can be defined as the average weather condition of a place measured over a long period of time (over 35 yrs).
Elements of climate include temperature, sunlight, wind, rainfall, relative humidity, pressure, radiant energy and cloud cover.
Temperature
This is the degree of hotness or coldness of a place at a given time. The effects on plants and animals include;
- It is essential for germination.
- It is essential for growth of plants.
- It is necessary for photosynthesis.
- It affects distribution of crops and
- animals.
- It affects maturity of crops i.e; ripening of fruits.
- It also determines the rate of evapotranspiration.
Sunlight
Plants need sunlight to grow.The energy that is generated by sun is also known as solar energy. The process whereby green plants make their food in the presence of sunlight is known as photosynthesis. The effects of sunlight on plants include the following:
- Sunlight is necessary for germination and maturity of seeds.
- It is the major source of energy for all living things.
- It is the major ingredients for photosynthesis.
- Sunlight account for the opening and closing of the petals of certain flowers e.g sunflower.
Sunlight affects the length of day, this is referred to as Classification of Crops Based on Amount of Sunlight Needed
Long-day plants which require longer day light.
For example, most cereal like millet, sorghum, spinach, etc.
Short-day plants which require shorter day light. For example cocoa, kola, tobacco, okro, soyabean and oil palm.
Day-neutral plants which require equal period of day and night, that is about 12 hours of sunlight and darkness respectively for example tomato, sun flower, maize, garden egg, etc.
Sunlight is equally essential for the performance and production of poultry.
It affects evapotranspiration. Absence of light lead to etiolation in which the plants leaves becomes pale and the stem elongated.
Wind
Wind refers to air in motion and account for the different seasons in the tropic.
It helps in the ripening of some fruits like cotton.
Wind affects the level of rainfall. It can either increase or reduce evaporation -transpiration.
Wind is essential for the dispersal of fruits and seeds. It is one of the agents of pollution. It can cause erosion it also causes serious damages to our crops in form of lodging.
Wind can spread diseases by carrying air borne spores and other pathogens.
It determines seasons in Nigeria. For example, south west trade wind brings rain while north east trade wind brings harmattan or dry season.
Rainfall
Rainfall is defined as the released of excess condensed water vapour in the atmosphere in to the earth, it has the highest effect on agricultural production in Nigeria.
Rainfall supplies drinking water for animals especially in the desert areas.
It determines the distribution and types of crops and animals that can be found in an area.
- Rainfall also determines the different types of vegetation.
- For example forest (south) and savannah regions (north).
- Rainfall is essential for seed germination and helps to dissolve soil nutrients.
- Excessive rainfall can cause soil erosion and leaching.
- It helps to dissolve nutrient in the soil, thereby making nutrient available to crop in the soil.
- It determine the season in Nigeria, raining and dry season
- It also determines when plant should be planted
- It also determines the types of crops to be grown
- It determines the type of livestock that can be raised in the different ecological zone
- Insufficient rainfall causes crop failure and poor yield.
Relative Humidity
This refers to the amount of moisture in the atmosphere.
Relative humidity results in the formation of rain.
High relative humidity can reduce temperature leading to coldness, and reduces evapo-
transpiration.
- High relative humidity leads to mouldiness of feeds in the poultry house.
- High relative humidity affects food intake and production of farm animals.
- High relative humidity also aids the growth of disease pathogens.
- Relative humidity determines the type of crops growing in an area. For example cocoa will not
grow well under low relative humidity while low humidity encourages the growth of grains and
grasses.
Cloud Cover
This influences temperature. It can determine rainfall of a place. It reduces evapo-transpiration. It affects growth of plants and feeding in poultry It affects sunlight intensity
Biotic Factors
These are living organism that affects agricultural production.
They include predators, parasite, soil organism( macro and micro-organisms) pest , disease pathogens and weeds.
Predators:
These are organisms that feed on other organism. Predators may include lizard, toad, hawk, tiger and lion while prey includes goat, chicks, and insects.
Some of them cause a great loss in livestock industry. Some predators are used to control some pests of crops and animals.
Parasites:
A parasite is an organism that live in or on other organism called host. It derives nourishment from the host while the host is injured during the association. It transmits certain diseases to the host egbabesiosis which is transmitted by tick
Parasites can live inside the host as endo-parasites such as tapeworm, roundworm and liver fluke.
They may also live outside the host asectoparasites such as ticks, lice and mite.
Parasites can also be plants such as parasitic weeds/epiphytic like dodder and mistotle.
They reduce the quantity and quantity of agricultural products. They may eventually lead to the death of plants and animals if not controlled on time.
Soil Organisms: These are living organism inhabiting the soil.
They include micro organisms like
bacteria, fungi and viruses and macro organisms such as earth worms, rodents,cricket,
millipedes, termites and snails etc.
Some of them cause diseases in farm animals and crop plant. For example bacteria and fungi
cause diseases.
Their activities can reduce the quality and quantity of agricultural yields.
Some of them are also beneficial in agricultural production. For example
Nitrogen fixes bacteria in the soil.
Fungi can help in humus formation and the decomposition of plant materials.
Some soil organisms also aid soil aeration, water percolation and fertility of the soil.
They help to breakdown organic matter in the soil and help in microbial digestion.
Pests: Pests are those organisms that cause physical damages to crop plants.
They include birds, rodents
They can attack crops while still growing on the field or during storage.
They can reduce yields of crops and animals.
They may increase cost of production
They reduce farmer’s income due to their effects on animals and crop yield.
Some pests are vectors of diseases.
Weeds: Weeds are plants growing where they are not desired.
They compete with crops for water, space, light and food nutrients. Some weeds are poisonous
to livestock.
They increase cost of production
It can also act as hosts for certain crop pests.Pathogen: These are diseases causing organism e.g. bacteria, viruses, fungi, protozoa, nematodes.
It increase the cost of production It reduce production yield It reduce farmers income It can lead to death of plants and animals
Edaphic Factors
These are soil related factors that affect agricultural production. The major soil factors include soil types, soil texture, soil structure, soil PH, and topography, etc.
Soil Type This is a serious factor in crop production. Soil types include sandy, loamy and clay soil.
It determines the kind of crop to be grown and It determines the irrigation type to be employed where needs be. It affects the performance of the crops. Soil Texture This refers to the relative proportion of sand, silt and clay in a soil sample.It determines the type of soil in an area.
Nutrient availability is also determined by soil texture.
It affects water infiltration and retention of the soil.
Erosion and leaching can either increase or decrease based on types of crops to be cultivated.
Soil Structure
This refers to the arrangement size and stability of soil aggregate or group.
Good soil structure aids the survival of soil organism which in turn aid soil fertility.
Good structure soil reduces soil erosion and flooding thereby helps soil conservation.
It also determines percolation rate and water retention capacity of the soil.
It determines the ease with which roots penetrate the soil and the ability to thrive well.
Soil pH
This refers to hydrogen ion (H+) concentration in the soil.
It is used to determine whether the soil is acidic, basic or neutral.
Soil pH determines the crop species that can grow in a habitat. For example tea grows well in
acidic soil while maize grows in slightly acidic soil.
Soil pH determines availability of soil organisms.
The quantity of soil nutrients varies with the soil pH. Aluminium, iron and manganese dissolve in
acid soils, than making them toxic to crop plants. Most tropical crops thrives well in a soil pH of
between 5.5 (slightly acidic) and 8.0 (alkaline). The color indicator commonly associated with
pH,
Acidic soil: Red color is commonly use.
Alkaline soil: Blueneutral: Green color
Universal Indicator pH range
Description Color <3 Strong acid Red
3-6 Weak acid Orange or yellow 7
NeutralGreen
8-11 Weak base Blue Soil Fertility A fertile soil is the one that contains all essential nutrients and water at the required proportion.
A fertile soil aids the production of food crops, cash crops, and forage crops. It minimizes the use of fertilizers and manures. It leads to reduction in cost of production. Topography/Land Relief
Topography refers to the shape of the land in relation to the underlying rocks of the earth’s surface.
Steep and gentle slope give rise to soil erosion It also aid weathering of rocks. Flat, gentle slopes land can be better site for intensive farming.
Presentation :
The topic is presented step by step
Step 1: The class teacher revises the old topic
Step 2: The class teacher introduces the new topic
Step 3: The class teacher allows the pupils to give their own contributions and gives room for pupils” participation
Class Teacher and Pupils Activities. Interaction or Participation
This involves class teacher and pupils’ interaction, conversation, imitation or modeling through discussion, play method or just by recitation or asking and answering questions that are related to the topic that has just been taught.
EVALUATION
1. Make a list of climatic factors that affect agricultural production.
2. Explain briefly how sunlight affects classification of crop plants.
3..Describe four effects each of:
- wind;
- rainfall;
- temperature; on agricultural production.
4. Itemise the edaphic factors that affect agricultural production.
5. Explain briefly how land relief feature can affect agricultural production.
6. How do soil texture and soil structure influence agricultural production.
7. Explain five ways in which high rainfall affects agricultural production.
(i) List six environmental factors affecting agricultural production. (ii) Explain three of the factors
8. Discuses five economic importance of pests and disease in agricultural production.
9. Explain briefly how the following affect crop production: (i) soil texture (ii) soil pH (iii) soil living organisms.
10. State two each of (i) climate (ii) biotic, and (iii) edaphic factors affecting production of crops and animals in your country.
Conclusion :
The class teacher concludes the lesson by giving the pupils some notes on the topic that has just been taught. He goes round to mark and he does the necessary corrections.
