Agricultural Science - Year 10 - Term 3 - Weeks 1,2,3,4,5,6,8,9,10
Irrigation System
Definition: Artificial application of water to soil to supplement rainfall, especially in areas with insufficient rainfall.
Sources of Water:
Rivers
Lakes
Streams
Ponds
Dams
Boreholes
Wells
Reservoirs
Reasons/Aims of Irrigation:
To soften the ground for tillage.
To cool the soil and atmosphere for favorable plant growth.
To provide crop insurance against drought.
To provide a cool environment for soil organisms.
To apply fertilizers (fertigation).
To enable multiple cropping cycles within a year.
To wash out or dilute excess salts in the soil.
Importance/Effects of Irrigation on Crop Production:
Softens soil for easy tillage.
Provides soil moisture for root absorption.
Reduces accumulated salt in topsoil.
Cools the soil during dry seasons.
Ensures crop establishment during erratic rainfall.
Increases crop yield.
Provides a humid environment for pests and pathogens.
Improves microbial decomposition of organic manure.
Dissolves nutrients for root absorption.
Facilitates year-round crop production.
Encourages the spread of weed seeds.
Factors to Consider When Choosing an Irrigation System:
Availability of water.
Slope of the land (Topography).
Soil type.
Types of crops.
Size of farmland.
Irrigation Systems/Types
Three Main Classes:
Surface irrigation
Sub-surface irrigation
Overhead irrigation
Surface Irrigation
Water flows along the surface of the land from rivers, dams, or streams.
Forms:
Channels
Flooding
Contour ditch
Furrow
Basin
Border dyke
Border ditch
Requires a gentle slope towards the farmland.
Factors to Consider in Choosing Surface Irrigation Method:
Topography of the land.
Soil type.
Type of crop.
Size of the farm land.
Advantages:
Removes excess water from heavy rainfall, especially in heavy soils.
Prevents accumulation of alkalis.
Easy to construct.
Increases microbial activities in the topsoil.
Cheap to establish and maintain.
Disadvantages:
Not suitable for hilly terrains.
Not successful in sandy soils.
Difficult to control water volume, especially in flooding.
Some crops may not tolerate heavy flooding.
Sub-Surface Irrigation
Water is applied below the soil surface to maintain an artificial water level.
Perforated pipes deliver water, reaching roots through capillary action.
Depends on:
Type of crop.
Nature of the soil.
Factors to Consider in Choosing Sub-Surface Irrigation Method:
Permeability of substratum.
Level of water table.
Soil texture or capillarity.
Soil structure.
Advantages:
Maintains water at optimum depth for crop needs.
High efficiency of water use.
Low evaporation losses.
Does not obstruct cultural practices.
Disadvantages:
High salt content water cannot be used.
Requires technical expertise.
Expensive.
Overhead Irrigation
Water is supplied above the soil surface.
Forms:
Sprinkler irrigation
Drip irrigation
Sprinkler Irrigation
Water is sprayed from the air through nozzles under high pressure.
Requires a pumping machine.
Advantages:
Regulated water supply.
Economizes water use.
Suitable for arid lands.
Soluble fertilizers and herbicides can be applied.
Disadvantages:
Costly to operate.
High wind velocity may affect distribution.
Requires stable water supply.
Lacks sufficient technical expertise.
Needs high power for pumping.
Drip Irrigation
Water is discharged through emitters or drippers near the plant base.
Reduces water loss through deep percolation, runoff, and evaporation.
Advantages:
Reduces salt concentration in the root zone.
Fertilizers can be applied.
Appropriate for arid and semi-arid regions.
Disadvantages:
Expensive to set up and maintain.
Uneven distribution on sloppy land.
High salt content water cannot be used.
Problems Associated with Irrigation
Inadequate water supply.
High cost of irrigation equipment and maintenance.
Invasion from pests of dry regions.
Increased disease due to high humidity.
Vectors of disease breed freely.
Lack of technical know-how.
Excessive salt dissolution prevents proper crop growth.
Potential pollution.
Disturbs farm machinery movement.
Reducing Disease Build-Up on Irrigated Farms
Use disease-resistant varieties.
Crop rotation.
Use appropriate chemicals.
Use clean tools and healthy planting materials.
Destroy diseased crops.
Weed control.
Avoid excessive irrigation.
Relationship Between Agriculture and Industries
Agriculture provides a market for industrial goods (e.g., farm machinery, fertilizers, pesticides).
Agriculture provides food for industrial workers.
Agriculture provides raw materials for industries (e.g., cocoa for beverage industries).
Drainage System
Definition: The artificial removal of excess water from the soil to promote good farming activities while retaining adequate reserve for crops during scarcity.
Importance/Effects of Drainage:
Reclaims waterlogged soil for crop production.
Improves soil structure and water-holding capacity.
Improves soil aeration for root respiration.
Provides suitable conditions for soil microbes responsible for decomposition.
Increases soil temperature.
Leaches excess salt from the soil, preventing plant poisoning.
Eases tillage.
Reduces crop diseases.
Enhances early planting.
Reduces soil acidity.
Drainage Systems/Types
Two Major Systems:
Surface drainage
Sub-surface (underground) drainage
Surface Drainage
The orderly removal of excess water from the surface using open ditches, field drains, land grading, and lateral ditches.
Advantages:
Relatively easy to construct.
Cheaper than sub-surface drainage.
Disadvantages:
Occupies space that could be used for planting.
Hinders machine passage.
Prone to gully erosion.
Requires frequent maintenance.
Increases farm hazards.
Underground or Sub-surface Drainage
The orderly removal of excess water using perforated pipes, tiles, or moles dug underground.
Advantages:
Does not pose a threat to machines.
More land available for cultivation.
Low maintenance cost.
Faster and more efficient drainage.
Suitable for deep, permeable soils.
Disadvantages:
Very expensive to operate.
Requires expertise.
Difficult to maintain.
Needs deep excavation, damaging soil structure.
Agricultural Pollution
Definition: Biotic and abiotic by-products of farming practices that result in contamination or degradation of the environment, ecosystems, and/or cause harm to humans and their economic interests.
Sources of Agricultural Pollution
Point Source Pollution: From a single discharge point.
Non-Point Source Pollution: Diffuse, landscape-level causes.
Abiotic Pollutants
Pesticides and Herbicides: Can contaminate soil, alter microbial processes, increase plant uptake, and cause toxicity. Leaching can contaminate groundwater.
Fertilizers: Excess Nitrogen and Phosphorus lead to groundwater contamination.
Organic Contaminants: Manures and bio solids contain nutrients but may also contain pharmaceuticals and personal care products.
Heavy Metals: From fertilizers, organic wastes, and industrial by-products, leading to accumulation in agricultural systems.
Land Management: Affects emission levels of greenhouse gases like nitrous oxide. Tillage levels can also affect nitrous oxide emissions.
Soil Erosion and Sedimentation: Intensive management contributes to soil erosion and sediment deposition, affecting water quality.
Biotic Sources
Greenhouse Gases from Faecal Waste: Livestock contribute directly or indirectly to anthropogenic greenhouse gases.
Bio pesticides: Derived from natural materials, may have negative impacts on non-target species.
Introduced Species: Globalization of agriculture has resulted in accidental transport of pests, weeds, and diseases to novel ranges, impacting native species and threatening agricultural production.
Biological Pest Control: Ecological issues include dispersal from agricultural habitats into natural environments.
Animal Management: Animal waste contributes to air, soil, and water pollution.
Effects of Agricultural Pollution
Health-Related Issues: Chemicals from fertilizers and pesticides contaminate drinking water, causing health problems, including blue baby syndrome.
Effect on Aquatic Animals: Fertilizers, manure, waste, and ammonia turn into nitrate, reducing oxygen in water and causing aquatic animal deaths. Bacteria and parasites from animal waste can pose serious health hazards.
Ways of Minimizing Agricultural Pollution (Control)
Quarantines: Legal instruments restricting movement of infested material.
Biological Control: Using predators, parasitoids, parasites, and pathogens to control agricultural pests.
Bio-pesticides: Derived from natural materials, safer to handle, and have a short residual time.
Anaerobic Digestion: Biological treatment of liquid animal waste to produce nutrient-rich liquid fertilizer and methane gas.
Simple Farm Tools
Tools used to make farm work easier and faster.
Examples and Uses:
Cutlass:
Digging holes for planting seeds.
Weeding.
Cutting and clearing bushes during land preparation.
Harvesting crops.
Felling trees.
Transplanting.
Hoes:
Digging holes during planting.
Making ridges, heaps, or mounds.
Weeding.
Making nursery beds.
Spade:
Digging house foundations, canals, drains, and trenches.
Lifting and turning of the soil.
Mixing concrete.
Leveling the soil.
Shovel:
Leveling the soil.
Mixing concrete.
Transferring manures.
Transferring soil.
Rake:
Leveling the soil.
Removing weeds, sticks, and stones from seedbeds.
Garden Fork:
Turning and picking up compost materials.
Removing weeds and trashes from the farmland.
Axe:
Falling big trees.
Splitting firewood.
Uprooting stumps during land preparation.
Pick Axe:
Breaking hard soil.
Removing stumps from the soil.
Mattock:
Removing stumps.
Removing stones from the field.
Bush clearing.
Hand Trowel:
Transplanting seedlings.
Light weeding on vegetable beds.
Mixing manure with the soil.
Sickle:
Harvesting cereal crops (rice, wheat, etc.).
Harvesting pasture grass.
Secateurs:
Trimming and pruning woody branches.
Preparation of cuttings for vegetative propagation.
Shears:
Trimming of flower hedges and shrubs.
Head pan:
Collecting harvested crops.
Mixing and carrying manures.
Carrying inputs and outputs on the farm.
Wheel barrow:
Carrying inputs and outputs on the farm.
Maintenance of Simple Farm Tools
I. Clean/wash tools after use.
II. Store in a cool and dry place.
III.Apply grease/oil on metal parts.
IV. Keep wooden tools away from termites.
V. Sharpen the sharp edges.
VI. Keep tools away from sun and rain.
VII. Repair/replace broken/worn out part.
VIII.Use tools for the right purpose.
Farm Machinery and Implements
Machines and implements used to make farm work easier, faster, and more profitable.
Examples
Farm Machines: Tractor, bulldozer, tree puller, dryer, sheller, incubator, milking machine, etc.
Farm Implements: Plough, harrow, ridger, cultivator, rotavator, etc.
Tractor
A powerful multipurpose motor vehicle used for lifting or pulling farm implements.
Equipped with a governor system.
Internal combustion engine (diesel or petrol).
Hydraulic control system for lifting mounted implements.
P.T.O (power take off) shaft for implements.
Driven on four wheels with rubber tires.
Types of Tractors
Wheel Type Tractor: Driven on wheels, has a PTO shaft for lifting and pulling implements.
Track Type Tractor: Moves on a track with chain and sprockets, often called a 'Bulldozer' or caterpillar.
Uses of the Tractor
Drawing farm implements (ploughs, harrows, etc.).
Stationary power source (shellers, threshers, grinders).
Carrying farm inputs, harvested products, and farm workers.
Hydraulic control system for lifting implements.
Daily Maintenance of Tractor
Keep clean.
Check water level, battery electrolyte, tire pressure.
Inspect tractor daily.
Adhere to manufacturer’s instructions.
Don’t overload the tractor.
Periodic Maintenance of Tractors
Service regularly.
Replace worn-out parts.
Check and retighten nuts, screws, or shields.
Grease linkages, steering, and moving parts regularly.
Wash and clean carburetor regularly.
Adjust or replace fan belt and service injector regularly.
Incubators
Machines used for hatching eggs (21 days).
Components of an Incubator
Setter
Hatcher
Heat source
Control unit
Heat distribution unit
Relative humidity unit
Felt tray
Thermometer
Air circulation unit
Egg turning device
Insulator
Turning device for egg tray
Milking Machine
Used for extracting milk mechanically.
Consists of an electric motor, vacuum pump, power source, vacuum controller, gauge, tank, and teat.
Shellers
Used for removing grains from cobs and pods.
Dryer
Used to reduce moisture content of farm products.
Maintenance
Store properly after use.
Sharpen blunt cutting edges.
Tighten bolts and nuts.
Lubricate metal and moving parts.
Replace worn-out parts.
Tractor Coupled Implements
Tools attached to and pulled by the tractor.
Plough
Primary tillage implement for cutting the soil into clods and turning it over.
Types of plough
Disc plough
Mouldboard plough.
The Disc Plough
Made up of concave discs mounted on a frame called the standard.
The standard is attached to the beam.
Features a furrow wheel and disc scrapper.
Suitable for working on heavy soil, stumpy soil.
Makes deeper cuts and buries weeds deeper than mouldboard plough.
How the Disc Plough Works
Beam carries the plough.
Coulter makes vertical cuts.
Share makes horizontal cuts & uproots weeds.
Mouldboard inverts the weeds.
Standard bears the mouldboard & the share.
Mould Plough
Suitable for temperate countries.
Made up of mould board, coulter etc.
Secondary Tillage Implements
Used after the plough (harrows, ridgers, planters, etc.).
Importance
To break down soil particles.
To kill weeds.
To incorporate weeds into the soil as manures.
Disc Harrow
Has many more discs than the plough.
Breaks the clod into fine particles.
It has the same parts and working principles with the plough.
The Cultivator
Helps in over turning obstacles.
Ridgers
Has the features of the plough with 5 discs – two discs facing each other to form ridges..
Made of strong metal; adapted for work in the tropics.
Used for making ridges.
Maintenance of Ploughs, Harrows, and Ridgers
Remove trash/mud before and after usage.
Tighten nuts, screws/shields, and caps.
Lubricate moving parts, joints, and bearings regularly.
Adhere strictly to manufacturers’ instructions.
Replace worn-out parts.
Keep implements in cool and dry sheds.
Use competent operators.
Planters
Containers for seed with features such as a hopper and furrow openers.
*Present infront of the hopper is a furrow opener and behind is a furrow covering device.
Harvesters
Used to harvest mature and ripe crops. Example of Harvesters such as combine harvesters, forage harvesters, corn pickers.
Sprayer
Used to spray agro-chemicals and liquid fertilizers. Examples of sprayer such as Knapsack or Boom Sprayer.
Agricultural Mechanization
The application of engineering principles and technology in agricultural production, storage, and processing on the farm.
Problems of Agricultural Mechanization
Land tenure system.
Scattered farm holdings.
Inadequate facilities (machinery).
Bad topography.
Varied soil types.
Inadequate spare parts.
Inadequate technical manpower.
Problems of stumps and logs.
Advantages of Agricultural Mechanization
Timeliness of operations.
Saves labor.
Reduces health hazards.
Reduces drudgery.
Encourages large-scale farming.
Leads to an increase in farm revenue.
Disadvantages of Agricultural Mechanization
Displacement of workers.
Compaction of soil.
Causes environmental pollution.
Few crops can be mechanized.
Expensive to operate.
Inadequate technical know-how.
Inadequate spare parts.
Limitation of Farm Mechanization
Economic limitation.
Technical limitation.
Lack of maintenance.
Small farm holdings.
Possible Ways of Improving Agriculture Through Mechanization
Farmers should be educated to accept modern systems of farming.
Loans should be provided to enable farmers to purchase farm machines.
Simple and less expensive machines should be developed.
Land tenure systems should be reviewed.
Farm Power
Power is the rate of doing work.
Sources of Farm Power
Human power
Animal power
Mechanical power
Electrical power
Wind power
Water power
Solar power
Biogas
Human Power
Power provided by man (family, hired, skilled, or unskilled).
Work Includes
Land preparation, planting, weeding, harvesting, storage processing, fertilizer application, etc.
*Normal human power is about W and decrease to about when continuously used.
Advantages
Man can control his work.
Useful for all operations.
Man can use his intelligence.
Readily available.
Disadvantages
Cannot perform tedious jobs.
Can be affected by health.
Skilled labor may be expensive.
Efficiency decreases with age.
Can be lost through death.
Takes time to complete a job.
Less efficient compared to machines.
Animal Power
Power supplied by work/draught animals (oxen, bullock, etc.).
Operations that Animal Power can perform
*Carrying of loads, farm inputs and people.
*Drawing of implements by yoked oxen and bullocks.
Advantages
Can be used for many operations.
Cheaper compared to mechanical power.
Animals don’t get tired easily.
Can perform more tedious operations than man.
Makes work easier.
Can be used to transport goods and personnel.
Disadvantages
Expensive to feed and maintain animals.
May be affected by pests and diseases.
Cannot work in the afternoon.
Only effective where there are no tsetse flies.
Not suitable for work in commercial farm.
State of health affects efficiency.
Can be lost through death.
Mechanical Power
Farm power provided by machines and implements.
Advantages
Very fast and efficient.
Can handle a large area of land quickly.
Cannot be affected by pests and diseases.
Performs a wide range of operations.
Makes work less tedious.
Disadvantages
Expensive (to buy and maintain).
Requires technical experts to operate.
Leads to unemployment.
Not easily available.
Movement of heavy equipment destroys soil texture.
Smoke causes pollution.
Electrical Power
Farm power derived from the use of electricity.
Advantages
A cheap source of power.
Can be used for various operations at the same time.
Saves labor.
Easy to operate.
Disadvantages
Supply is irregular in developing countries.
Expensive when generators are used.
Dangerous if not properly handled.
Cannot be used for field operations.
Wind Power
Power generated by the movement of wind.
Advantages
Cheap (available everywhere).
Alternative to electrical power.
Disadvantages
Not stable.
Limited to certain operations.
Cannot be stored.
Difficult to control.
Water Power
The power is derived from water in rivers, streams, dams, etc.
Advantages
Cheap.
Can be converted to other sources of power (electricity).
Easy to harness.
Disadvantages
Low level of water affects generation.
Not available everywhere.
Does not supply power directly.
Supply is affected by season/weather.
Can be destructive.
Solar Power
Farm power derived from the radiation of the sun.
Advantages
Cheap and free.
Easily available.
Neat source of power.
Disadvantages
Only available during the day.
Cannot be stored or controlled.
Expensive to store/harness.
Supply is seasonal.
*### Biogas
Farm power generated from animal feces (dungs).
Advantages
Converts chemical power in dung to heat power.
Can be used for cooking, drying, and heating.
Easy to control.
Disadvantages
Not a common source of power.
Requires expertise.
Expensive to set up and maintain.
Only possible where animals are reared on a commercial basis.
Farm Surveying
The process by which measurement of land is made on the farm or the measuring and mapping out of the position, size and boundaries of an area on farmland..
Importance of Farm Surveying
Determine the hectare of land.
Exposes the gradient of the land.
Helps to make decisions on locations of various farm building and structure.
Helps determine the amount of fertilizer, labor, seeds, and chemicals to be used.
Enables farmers to make the best use of available resources.
Loans can be got with the help of farm survey plans.
Gives the owner of the land security.
Does not allow wastage of land.
Can be used as a basis of feasibility studies.
Common Surveying Equipments
Ranging Pole
Günter's Chain
Measuring Tapes
Prismatic Compass
Theodolite
Arrows or Pins
Offset Staff
Beacon or Pillar
Ranging Pole
Made of wood or metal with varying lengths, circular in section.
It is used for marking stations.
It is used for making straight line
Gunter's Chain
Consists of a series of dumb bell shaped series link of steel wires. The length of the chain is .
Use:
It is used in taking short or detailed measurement of length and breadth
Measuring Tapes
*Made of linen or fine steel sheet, marked in metric units.
Uses
It is used for taking measurement of length breadth and height
Prismatic Compass
It has a prism with a compass card marked in degrees, half degrees, minutes, and seconds, in a clock wise direction
Uses
It is used in taking bearings.and measures angular distances
Theodolite
It consists of a tripod stand, and spirit level. It is mainly use to measured horizontal or vertical angles or planes
Arrows or Pins
These are thin pointed steel wires of about 30cm long with one end curved into a ring. A red cloth is normally attached to the ring.
uses
it is used to mark chains lengths during chaining. also to mark stations
Offset Staff
This is a graduated rod 3m long, a hook may be fitted at the top for the purpose of pulling a chain through a hedge. It is used for taking short measurements of Offsets
Beacon or Pillar
It is made of rectangular block usually in concrete form, marks are usually inscribed on top of the block. They are always buried in the ground with the marked head raised a little above ground. They are used for marking off points measured and recognition of measure and survey the area
Precautions In Survey of Farmland
Pull taut chains, tapes, or ropes.
Avoid errors of transposing figures on papers.
Equipment such as theodolite should be placed on a perfect horizontal plane.
All chains, tapes, ropes, etc., must be properly aligned before taking measurement.
Avoid the error of parallax when reading measurements.
Make sure the chain is not faulty before use.
Farm Planning and Principles of Farmstead Planning
Farm planning is the drawing or outline of a farmstead.
Importance of Farm Planning
Enables proper use of the land.
Ensures proper siting of buildings.
Ensures the location of livestock buildings in relation to other farm buildings.
Promotes neatness and prevents pollution within the farmstead.
It allows for proper utilization of resources without wastage.
It makes the farmer to be more responsive to market demand.
It encourages efficiency of farm activities
It makes coordination and control of farm operation easier.
Factors Affecting the Siting of a Farm/Farmstead
Topography
Soil type
Accessibility
Water supply
Health/Hygiene
Nearness to market
Drainage
Principles of Farmstead Layout
Plant crops on the best soil.
Locate livestock buildings on the poorest soil.
Locate buildings in easily accessible areas.
Locate farm buildings on slopes to avoid erosion.
Locate residential and office buildings away from livestock buildings.
Calculating Area of Farm Land and Plant Population
Area of farmland depends on the shape of the land.
*Number of plant stand or population=Spacing: distance between plants, e.g.,
Example Calculation:
Given: A school farm with dimensions , , and .
a. Calculate the area of the land in hectares
b. the school plans to cultivate plantain at a spacing of 4m X 4m on 80% of the land and pineapple at a spacing of 2m X 2.5m on 20% of the land, calculate the number of plantain and pineapple planting materials that would be required for the farm.
Solution
Area of land =
Conversion of the area into hectares: since 1 hectare = 10,000 m^2
Area of land in hectare =hectare
Area of cultivating plantain = Area of farmland % land for plantain
Spacing of plantain =
Plantain population stands of plantain
Area for cultivating pineapple = Area of farmland Area occupied by plantain
Spacing for Pineapple =
Pineapple population = stands of pineapple