FARM POWER AND MACHINERY

Introduction

• Farm power is any form of energy used in the farm to do work.             .

Sources of Farm Power

Human Power

• Performs light tasks.
• Quality of work produced is variable.
• Takes a long time to complete a task.

Animal Power

• Done by draught animals such as camels, donkeys, horses and elephants.
• Used in land preparation and transportation.

Disadvantages

• Slow.
• Animals are liable to sickness and get tired.
• Need enough food.

Wind Power

• To pump water from boreholes.
• To winnow crops such as beans, finger millet and rice.
• Generate electricity.

Disadvantages

• Not easy to control and may not be available when needed.

Water Power

• Irrigation.
• Grinding mills (to grind maize grains).

Disadvantages

• Difficult to use in the farm because it is not easy to control.

Biomas

This includes:

• wood or charcoal
• biogas power.

Charcoal/Wood Fuel Energy

Uses

• Provides heat for boiling water and cooking.
• Dehydrating of some crops.
• Curing of tobacco.

Disadvantages

• Exhaustible.
• It cannot be used directly in some farm operations.
• Large quantities are required.
• They are bulky hence difficult to transport.

Biogas

Uses

• Provides heat and light for cooking, boiling water and lighting.
• Produces electricity.

Disadvantages

• Only possible where there are animals under zero grazing unit.
• It is labour-consuming.
• Large quantities of dung are required.
• Cannot be used directly in some farm operations.

Fossil Fuels

These include:

• coal,
• petroleum oils
• natural gas.

Uses

• Petrol or diesel is burned in internal combustion engines to produce power.
• Kerosene is the main source of power to light rural homes.
• Natural gas is used for cooking, heating and lighting.

Electrical Power

It includes:

• hydro-electrical power (HEP),
• geothermal,
• nuclear
• power stored in batteries.
• Nuclear energy is a potential source of power which has not yet been used in the farms.

Uses of Electrical Power

• Runs stationary machines such as milling machines, grinding mills, cooling machines and water pumps.
• Supplies heat and light for operations of brooders.

Disadvantages

• Cannot be used directly in some farm operations.
• Lack of electricity in the rural areas.
• Power failures can lead to high losses.
• It is costly to install and maintain.

 

Solar Energy

Energy obtained from the sun.

Uses

• Provides heat and light.
• Used by all the plants in photosynthesis.
• Dehydrating crops such as vegetables, maize grains, beans and hay.
• Boils water which drives turbines to produce power for minor uses.

Disadvantage

• Low concentration of energy on cloudy d
• Expensive In collecting and concentrating equipment.
• Cannot be used directly in some farm operation
• Requires skilled labour to install and maintain.

Tractor

• The tractor has an internal combustion engine which burns petrol or diesel to produce power.
• This power is then passed to the gear box from where it is transmitted in various ways.
• The common tractor engine is a four stroke cycle engine.

The four strokes are:

• Induction stroke.
• Compression stroke.
• Power stroke.
• Exhaust stroke.

Induction Stroke

• Piston moves down.
• Inlet valve opens.
• Fuel and air get into the cylinder.

Compression Stroke

• Inlet valve is closed.
• Piston moves up the cylinder.
• Fuel-air mixture is compressed.

Power Stroke

• A spark is produced at spark plug, igniting the fuel-air mixture.
• The increased pressure forces the piston down the cylinder.

Exhaust Stroke –

• Exhaust valve opens.
• Piston moves up the cylinder.
• Burned fuel-air mixture expelled.

 

Advantages of the Four Stroke Engines

• Produce high power which can do heavy farm work.
• Have efficient fuel and oil utilization.
• Perform a wide range of farm operations.
• Are effectively cooled with water thus allowing the production of large engine size.
• Exhaust gasses are effectively expelled from the cylinders.

 

Disadvantages

• Are expensive to buy and maintain
• Their use is limited in some areas;
• Tractor can only be used on flat or gently sloping areas
• Require skilled personnel and support services

 

The Two Stroke Engines

• Found in small machines such as mowers, motor bikes, and water pumps which do light jobs in the farm.
• All the cycles are completed in two strokes of the piston.

        These strokes are;

Induction and compression stroke

• The piston is at the bottom
• Piston moves up uncovering the inlet port
• Fuel-air mixure is drawn in
• Ignition occurs when the piston reaches the top
• Piston is forced downward compressing the mixture in the crank.

Power and exhaust stroke

• The piston is at the top
• Ignited gases produce pressure which force the piston downwards
• The piston covers the inlet port and traps fresh fuel-air mixture in the crank case
• Piston moves further down to uncover the exhaust port
• Fuel-air mixture transferred from the crankcase to the combustion chamber.

What Advantages of two stroke engine?

• Cheap to buy and easy to maintain
• Economical in fuel consumption
• Can be used in a wide  range of farmland, including hilly areas
• Can do small tasks in the farm which would be un-economical to do using the four stroke engine.

What disadvantages of two stroke engine?

• They produce less power hence cannot be used for heavy duties.
• They are inefficient in burning fuel to produce power.
• They are air cooled thus limiting the size of the engine.

Systems of a Tractor

The modern tractor has the following systems:

• The fuel system.
• Electrical system
• Ignition system
• Cooling system
• Power transmission system.

The Fuel System

Supplies fuel to the engine.

Categorized into two types depending on the fuel used.

These are:

• The petrol fuel system.
• The diesel fuel system

The Petrol Fuel System

Consists of:

Fuel tank – storage of fuel.

Fuel filter – removes foreign particles from the fuel.

Carburettor –

• atomises fuel into spray.
• introduces fuel-air mixture into the engines.
• Regulates fuel-air into suitable proportion

Fuel pump – forces fuel into the carburettor.

Delivery pipe – connects all the devices.

 

Maintenance

• Cleaning the carburettor regularly.
• Cleaning the fuel filter in petrol.
• Cleaning the hole in the fuel tank cap.

The Diesel Fuel System

Consists of:

• Fuel tank – storage of fuel.
• Fuel injection pump – pumps diesel through injection nozzles and breaks into fine spray.
• Fuel filters – remove foreign particles from the fuel.
• Delivery pipes – connect the various devices.

 Maintenance

• Replacing the fuel filter.
• Bleeding in case air is trapped in the system.
• Cleaning the sediment bowl regularly.

Electrical System

Consists of the following:

Battery

• Converts chemical energy into electrical energy.
• Stores electrical energy produced by the running

Ignition circuit – provide the electrical required by the spark plugs.

current that produces a spark in the engine.

Generator circuit – provide the electrical current that starts the engine.

Lighting circuit – supply the electrical current required for the lighting system.

Starter motor circuit – starts the engine.

 

Care and Maintenance of a Tractor Battery

• The level of electrolyte should be kept just above the plate by topping with distilled water.
• Corroded terminals should be scrapped clean and smeared with grease.
• The battery should be tightly fixed in a box to avoid spillage and damage.
• The battery should be fitted correctly on the tractor.
• The battery should be charged regularly and periodically.
• In case of long storage the battery contents should be kept upside down.
• The generator fan belt should always be functional to ensure the battery is always charged.

 

 Ignition System

Consists of:

Ignition – change the low voltage from the battery to high voltage current  required by the spark plugs.

Condenser – absorbs the self-induced current in the primary circuit.

• stores current for a short time.
• passes electric current to the distribut

Distributor – distributes the high voltage current to the spark plugs.

Contact breaker – Interrupts the normal flow of current in the primary circuit.

State the Maintenance practices carried on  the Ignition System

• The carbon deposits on the spark plug electrodes should be removed.
• The spark plugs whose electrodes are worn out should be replaced.
• The contact breaker points should be cleaned.
• The breaker points should be adjusted so that they lie between O.30mm and 0.50mm.
• The condenser should be replaced regularly.
• The ignition systems should always be kept dry.
• Ignition wires with poor insulation should be replaced.

Cooling System

• The cooling system aims at preventing the engine from overheating which would cause piston zeisure in the cylinder.
• Some tractor engines are cooled by air while others are cooled by water.

State the Characteristics of Air Cooled Engines

• They are simple in construction.
• They have fins and a fan blade which assists the circulation.
• They are light in weight for they have no radiators and water jack

 Limitations

• They get hot quickly and use heavy lubricating oil.
• The cooling is not adequate under all conditions especially when carrying heavy load

Water Cooled Systems

• It consists of the radiator, water jackets, water hoses, water pump, thermostat and a fanning mechanism.
• Water is used to absorb heat from the engine block at a reasonable rate.

 Care and Maintenance of Water Cooling system

• The water pumps should be lubricated regularly.
• Clean water should be used in the radiator and trash removed from the fins.
• All pipes should be fitted tightly to avoid blockage.
• The radiator should be filled with clean water before starting the day’s work.
• Fan belt tension should be checked regularly and if too tight or too loose should be adjusted accordingly.

Lubrication System

• This system is aimed at supplying oil to all parts of the engine where friction is likely to occur.

Importance of Lubrication system

• It helps to increase the efficiency of the machine and reduces the rate of wear and tear of moving parts.
• It reduces the heat created by the rubbing surfaces and acts as a seal between them.
• It acts as a cleaning agent because it washes off all the dust, dirt, soot and metal chippings from the oil paths to the sump.

Types of Lubrication Systems;

• Splash feed type
• Force feed type
• Oil mist type

Types of Lubricants

• SAE 10 – This is thin engine oil which gives little protection when heated.
• SAE 50 – This is thicker engine oil which is recommended for protecting the bearings.
• SAE 90 – 100 – These are transmission oils which are recommended for clutch, gear box, wheel lubrication and ball bearings.

      Note: SAE – Society of Automobile Engines.

Care and Maintenance of Lubrication Systems

• Old or contaminated oil should not be used for lubrication.
• Oil should be drained when still hot to avoid sticking on the walls of the sump.
• The oil filters should be replaced when necessary.
• The correct type of oil should be used as per the manufacturers’ instructions.

Power Transmission System

• The function of this system is to transfer power from the tractor engine to the drive shaft, the wheel axle, the power take off shaft and the hydraulic system.
• The system consists of the clutch, gear box, differential and the final drive.

The power transmitted from the engine is made available for use through the following:

• The propeller shaft – it connects the gear box to the differential.
• The power take off shaft (PTO shaft)­ -It is located at the rear part of the tractor and rotates at the same speed as the crankshaft of the engine.
• Hydraulic system – it is operated by the use of a lever near the drivers seat.
•  It is connected to the 3-point linkage and helps to lower or raise implements mounted on the 3-point linkages such as ploughs, mowers, planters and sprayers.
• Draw bar –

• It is a one-point linkage at the rear part of the tract
• It serves for the attachment of trailed implements that can be used during harrowing, transportation or rolling.

Tractor Servicing

• The aim of tractor servicing is to keep the tractor in good and efficient working conditions.
• Tractor servicing is either;
• short
• long term.

List the Short Term Tractor Servicing

 It includes:

• Checking the engine oil daily by use of a dip stick.
• If the oil level is low, it should be added.
• The fuel level should be checked at the start of every day’s work and added if necessary.
• Water level in the radiator should be checked and if possible topped up.
• The level of the electrolyte should be checked daily and topped up with distilled water accordingly.
• Nuts and bolts should be tightened every day.
• Lost nuts and bolts should be replaced before the day’s work.
• Grease should be applied by use of grease gun through the nipples.
• Large sediments from the sediments bowl should be removed.
• The tyre pressure should be checked daily before the day’s work.
• The fan belt tension should be checked to ensure that it deflects between 1.9cm and 2.5cm when pushed.
• The brake shaft bearing should be greased.
• The brake fluid level is maintained at the recommended level.

Long Term Services

• The engine oil should be drained completely from the oil sump and replaced with new oil.
• The gear box oil should be checked and refilled as recommended.
• The oil in the differential should be replaced as recommended.
• The linkage and the pulley attachment should be greased.
• The pulley oil level should be checked and added if need be.
• The dirty oil should be removed and replaced with clean one.

 

Farm Machinery

Tractor Drawn Implements

• These are implements which are attached to the tractor during opera

State the two categories. Tractor Drawn Implements

One–point hitch implements ;

• Are attached to the tractor at only one point that is, the draw bar.
• They include all trailed implements such as the trailers, heavy harrows, planters and roller

Three point hitch implements;

• Are implements attached to the tractor at three points that is, the top linkage point and two lower linkage point
• They are operated by the hydraulic system.
• They include ploughs, most harrows, sub­soiler, planters, mower, ridgers, sprayers and rotavators.

 

Trailers

• They are one-point hitch implements.
• They are used for transportation of goods.
• Small ones have two wheels while big ones have four wheels.

 

Maintenance

• All the moving parts should be lubricated.
• Tyre pressure should be adjusted to the correct pressure.
• Worn out tyres should be replaced.
• Loose nuts and bolts should be tightened, worn-out ones should be replaced.
• The implements should be kept under a shed during long storage.

 

Ploughs

• They are primary tillage implements.
• The common type of ploughs include:
• Disc plough
• Mould board ploughs.

Disc ploughs

• It is made up of heavy steel concave discs of 60-70cm diameter.

Parts and Functions of a disc plough

The hitchmast:

• Is an attachment for the three point hitch.
• Made up of two side links and a top link.
• These are parts connected to hydraulic system of a tractor for lifting and pulling.
• The beam: Supports all other parts. It also adds weight for better penetrati
• Depth wheel:
  • Used when driving on highway,
  • it also controls the depth of plou
  • May not be present in all disc ploughs.
• The standard or leg: Connects the discs to the beam.
• The hub: Allows the discs to rotate smoothly hence does the cutting of furrow slices.
• The scrapers: Remove the trash and mud or soil which cling to the discs,
• Disc blades: Cut and invert the furrow slice
• Rear furrow wheel: Controls the depth of digging and stabilises the discs.

 

Adjustment                .

• The cutting angle should be adjusted at 35° – 50° from the I ine of travel.

Achieved by pivoting the beam or the standard.

• Depth of digging: This is corrected by changing the height of depth wheel or adjusting hydraulic system and adding weight

Care and Maintenance of Disc Plough

• Check for loose nuts and bolts and replace them.
• Sharpen the disc blades if blunt.
• Lubricate the rotating parts by use of oil/grease to reduce friction.
• Paint the exposed parts for example the beam/framework.
• Clean the implement at the end of each day’s work before storage.
• Store the implements in a shed.
• The unpainted parts should be coated with old engine oil to prevent rust.

Uses of a Disc Plough

      Used in areas with the following conditions:

• Virgin land with many obstacles.

• Land with too much trash or tall vegeta

• Opening up pasture land.

Mouldboard ploughs

• This primary tillage implement is suited in areas without obstacles such as stones, tree stumps, and roots.
• It gives a uniform depth of ploughing.

Parts and Functions Mouldboard ploughs

• Share: This makes the horizontal cut and starts the turning of the furrow slices.
• Mouldboard: Continues the turning of the furrow slices and pulverizes the soil.
• Disc coulter: Makes a vertical cut in the soil to separate the furrow slice from the un-ploughed land.
• Skim coulter: Removes any trash from between the furrow slices.
• Frog: It is the part where the share, mould board and the landside are attach
• Landside: Stabilizes the plough and absorbs the side forces created when furrow is turned.
• Shin: Leading edge of a mouldboard.
• Knife coulter: Is a vertical knife which cuts trash and earth ahead of the share.

 

Care and Maintenance

• Lubricate the rolling parts for example wheel bearings and disc coulter bearings.
• Paint scratched parts of the plough.
• Sharpen the share or replace if worn out.
• Check all loose nuts and bolts and replace where necessary.
• Clean the implement after each day’s work to remove soil, mud and trash.
• For long storage, keep under a shed and apply lubricants.

Adjustment

Depth:

• Controlled by raising or lowering the depth wheel.
• Controlled by hydraulic control lever setting.

Pitch: controlled by altering the length of the top li

Front furrow width: Controlled by cross shaft adjustment lever or by rotating the cross shaft crank.

Lateral levelling: Controlled by tractor lift rod.

Harrows

• They are secondary cultivation implements.
• There are different types of harrows.
• The common ones are:

disc, Harrows

spring tine Harrows

spike tooth harrows.

 

Disc Harrows

• It comprises of a set of gangs with concave discs.

Uses

• Mixing the soil particles.
• Levelling the seedbed by breaking large
• lumps of soil.
• Killing weeds.

 

Disk harrows can be classified according to the arrangement of the gangs such a;

• s tandem,
• double tandem
• offset tandem.

Depth Adjustment

• Adding weights on the harrows.
• Use of hydraulic force.
• Use of light or heavy harrows.
• Use of regulating wheels.

Care and Maintenance

• Check for loose nuts and bolts daily.
• Lubricate the shafts and bearings.
• Clean and oil before storage.

Spring Tine Harrow

• Is made up of flat and curved tines which act as springs.

    Uses

• Levels and smoothens the seedbed.
• Breaks the soil clods.
• Mixes trash and soil thus preventing wind erosion.
•  Aerates the soil.

Adjustments

• Depth is controlled by the horizontal connecting link and depth wheel.
• For individual tine, use crossbar and loosening the screws.

Care and Maintenance

• Check for loose nuts and bolts and tighten them if necessary.
• Clean after use.
• Oil the lever mechanism.

 

 Spike Tooth Harrows

• Consists of a metal framework with rigid metal spikes which break up the soil by vigorously hitting large lumps of soils as it is pulled through the soil.

      Uses

• It smoothens and compacts the soil.
• It breaks big lumps of soil into small particles.
• Can be used for cultivating small crops if well set.

Subsoilers

• Heavy and require high horse power to pull.
• Ploughing depth of 51-90cm.

 

Functions

• Break up compacted soil.
• Break up the hardpan.

Care and Maintenance

• Clean it after use
• Check the point and if worn out, replace it.
• Oil when not in use.

Ridger

• It is double mould board plough used to make ridges and furrow
• It is used to prevent water logging and draining through furrows for easy harvesting of root crops.

 

Rollers

• This is an equipment used to compact the soil gently especially where tiny seeds are to be planted.

Rotavators: (Rotary cultivators)

• Work on the principles of high speed of revolving flail blades which beat and cut the soil together with trash.
• It is an equipment for both primary and secondary tillage operations.
• It is driven by the P.T.O. shaft of a tractor.

    Uses

• Breaks up large soil particles into small ones.
• Mixes the vegetation and the soil.
• Achieves two operations in one pass.

    Adjustments

• Forward speed of the tractor gives a fine tilth of the seedbed done through the gearbox.
• Depth of work done by control of depth wheel.
• Slip clutch may break in case the knives come across obstructions

 Mowers

Uses

• Cutting grass for hay or silage making,
• cutting overgrown grass
• clearing the field.

Reciprocating Mower

Parts and Functions

• Swath stick: Keeps the cut crop falling correctly.

• Swath board: To remove the cut crop.
• Shoe: Has a runner to absorb the weight and wear.
• Cutter bar: Is a flat bar which guides the fingers.

• Wear plate: Counteracts downward force and holds the knives.

      Adjustments

• To adjust knife register by moving the whole bar away or towards the yoke.
• Knife lead: The outer shoe should be adjusted to be outer than the inner shoe by 4cm.

Maintenance

• Check for loose nuts and bolts and tighten where necessary.
• Keep knife section sharp.
• Lubricate the knife parts.
• Check knife to ledger plate cup for best cutting.
• Keep all the parts tight.

Rotary Mowers

• Cutting edge consists of two blades fitted opposite to each other on horizontal disc.
• The cutting blades swing round at high speed horizontally to the ground hence cutting is effected.

Adjustment and Maintenance

• Blades should be sharp.

• Guards to be fitted around the blades to protect the operator from flying objects.

• Lubricate the P.T.O. shafts.
• Check the gear-box oil regularly and fill to the right level if necessary.

Planters

• They are machines used for sowing seeds.

• There are two types:

• Row crop planters.
• Seed drills.

 

Functions of the Planters

• Meter the seed and fertilizers from seed and fertilizer
• Open the seed furrow.
• Deposit the seed in the furrow through the delivery tubes.
• Cover the seed

 

Functions of Parts of a Seed Plate

• Filler plate: gives proper seed depth.
• False ring: allows the seed to fall from the seed plate into the boot.
• Knockout pawl: pushes the seeds out of the cell by the roller action.
• Cut-off pawl: prevents more than one seed remaining in a plate cell.
• Cells: shaped holes to hold the seed.

 

Adjustments

• Adjust the coulters depth for the right crop.
• Fix the right seed plate.
• Place the planter in the level position.
• All the shafts should be free to turn.

 

Care and Maintenance

• Check all loose nuts, bolts and tighten them.
• Clean and oil the planter after use.
• Grease the drive sprockets regularly.

 

Seeders

• The grain drill sows grains of wheat, barley, oats, peas, beans and alfalfa seeds.

Parts that can be adjusted to change the sowing rate;

• Select the side of the feed wheel recommended on the drill charts for the seed-rate.
• Change the speed of the wheels by changing the gears or sprockets or both.
• Change the position of the feed gate in the cup.

• Use reducers below the feed wheel.

Care and Maintenance

• Keep seed and fertilizer hoppers dry and clean after each day’s work.
• Check the drive shaft and lubricate them.
• Paint the parts for example fertilizer
• hopper to be shiny

 

Combine Harvester

     Use

• Harvesting cereal crops for example maize, wheat and barley.

It is designed to do the following:

• Cutting
• Threshin
• Winnowing
• Bagging

Parts of a Combine Harvester

• Cutter bar – cuts the grain head.
• Pick up reel- direct crop into the cutter bar,
• Elevator – channels the cut grain to the threshing drum.
• Winnowing ran – fans trash up onto a straw walker and directs it out of the combine harvester.
• Delivery tube – delivers the clean .grains into a collecting tank from where it is bagged.

Maintenance of a Combine Harvester

• Loose nuts and bolts should be tightened.
• Remove all foreign materials stuck in the machine at the end of the day’s work.

Ridgers

• They are used for harvesting tuber crops and for making furrows or ridges.

     Maintenance

• Lubricate the moving parts.
• Clean the implement after use.
• Store under a shed.
• Repair or replace worn-out or broken parts.
• Loose nuts and bolts should be tightened.
• Unpainted parts should be oiled during long storage.
• Shares should be sharpened if blunt.

Foragers

• They are tractor mounted and operated by power from the P.T.O. shaft .
• Used for harvesting forage crops such as Napier grass, sorghum and maize.

    Maintenance

• Tighten loose nuts and bolts.
• Lubricate moving parts.
• Store in a shed.
• Clean after the day’s work.
• Repair/replace worn out or broken parts.
• Unpainted parts should be oiled to prevent rust.

 

Maize Shellers

• These are stationary implements which are either hand or tractor driven.
• They consist of. a rotating disc which shell maize grains from cobs.

 

Maintenance

• Greasing moving parts.
• Removing any stuck maize cobs.
• Repair or replace worn out or broken parts.
• Store in a shed.

Animal Drawn Implements

Ox Plough

• Ox-plough is a simple type of a mouldboard plough which is pulled by a pair of oxen, donkeys or camels.

Explain the functions of the following parts of an ox-plough

• Main beam – It is the main component onto which all the other parts are attached.
• Mouldboard – It inverts the cut furrow slice upside down.
• Plough share -It cuts the furrow slices.
• Land wheel- It regulates the depth of plough.
• Draft rod – It is on this rod that a chain is connected on which a yoke is linked.
• It forms the draught mechanism of the plough.

What are the Advantages of an Ox-Plough Over Tractor­ Drawn Plough ?

• Less skill is required to operate it.
• Useful where tractors cannot be used for example steep slopes.
• Cheap to buy and maintain.

 What are the disadvantages of an Ox-Plough Over Tractor­ Drawn Plough ?

• Much time is wasted in training oxen.
• Tedious and laborious to the driver of the animals and the controller of the implement.
• Animals can be sick or in poor physical state.
• Extra land is required as grazing fields for the oxen.

 

Adjustments

• Depth of plough is controlled by the land wheel and draft rod

 

Care and Maintenance

• Sharpen or replacing of the worn out share
• Replacement of worn out parts such as hooks and draw bar assembly.
• Oiling the shiny parts e.g  mouldboard
• Wash off the soil after use.
• Paint the handles, beam and braces to prevent rusting.

 

Ox-Drawn Cart

• These are small carriages harnessed to the animals by a yoke
• The small carts have only two wheels bigger ones have four.
• They are pulled by animals in singles or in pairs
• Carts are used for transport.

Maintenance

• Moving parts should be oiled
• The yoke should be repaired when worn out or replaced if not repaired
• Tyre pressure should be checked and adjusted accordingly
• Repair other damages on the cart.