Lesson Notes By Weeks and Term v4 - SHS 1
AGRICULTURAL MACHINERIES
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AGRICULTURAL MACHINERIES
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Subject: Agricultural Science
Class: SHS 1
Term: 1st Term
Week: 8
Grade code: 1.1.3.LI.2
Strand code: 1
Sub-strand code: 3
Content standard code: 1.1.3.CS.2
Indicator code: 1.1.3.LI.2
Theme: NEW DAWN IN AGRICULTURE
Subtheme: AGRICULTURAL MACHINERIES
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Welcome, future leaders of Ghana's agriculture! For centuries, our farmers have used tools like the hoe and cutlass. While effective for small farms, these tools involve a lot of hard work (drudgery) and limit the amount of land one person can cultivate. To feed our growing population and turn farming into a profitable business, we must embrace modern technology. This is where agricultural machinery comes in. This lesson will introduce you to the powerful machines that are transforming farming in Ghana and around the world. We will learn how to group them based on their function and understand the basic principles of how they work.
A. What is Agricultural Machinery?
Agricultural Machinery refers to complex mechanical devices and vehicles used in farming to reduce human labour and improve efficiency. They are usually powered by an engine. Key Difference from Farm Tools: A farm tool (like a hoe, cutlass, or shovel) is a simple implement powered by human muscle. A machine (like a tractor or combine harvester) uses a power source (e.g., a diesel engine) to perform work on a much larger scale.
The most important machine on a modern farm is the Tractor. Tractor: A powerful motor vehicle with large rear wheels, used for pulling other farm implements. It provides the power for most other machines through: The Drawbar: A bar at the back to pull implements like ploughs and harrows. The Power Take-Off (PTO) Shaft: A rotating shaft at the back that powers machines with moving parts, like sprayers or harvesters. Hydraulic System: Uses fluid pressure to lift and lower heavy implements. B. Classification of Farm Machinery by Function
We can classify farm machinery based on the stage of crop production at which they are used. Tillage Machinery (For Land Preparation) Tillage is the process of preparing the soil for planting. Primary Tillage: The initial, deep breaking and loosening of the soil. Ploughs: Used to cut, lift, and turn over the topsoil. This buries weeds, loosens the soil for roots and water, and brings nutrients to the surface. Mouldboard Plough: The classic plough. It has a curved plate (the mouldboard) that completely inverts the soil slice. Best for loamy soils. Disc Plough: Consists of a series of large, sharp, concave steel discs. It is better for hard, dry, or sticky soils and land with many roots and stones, as the discs can roll over obstacles. Secondary Tillage: Operations that follow primary tillage to create a fine, level seedbed. Harrows: Used to break up large soil clods left by the plough, remove weeds, and create a smooth surface for planting. Disc Harrow: Similar to a disc plough but with smaller discs, used for finer tilling. Spike-tooth Harrow: A frame with rigid spikes that are dragged through the soil. Rotavator (or Rotary Tiller): Has rotating blades that actively churn and mix the soil. It can sometimes perform both primary and secondary tillage in one pass on lighter soils. Planting/Sowing Machinery These machines place seeds or seedlings into the prepared soil. Planters: Used for sowing large seeds like maize, beans, and groundnuts. They are designed to place seeds at a specific depth and spacing. How it works: A furrow opener creates a small trench, a metering device drops a seed (or a set number of seeds) into it, and covering wheels push soil back over the seed. Seed Drills: Used for sowing small-grained crops like rice or wheat. They sow seeds in continuous rows rather than at specific intervals. Transplanters: Used to plant seedlings that have been raised in a nursery (e.g., rice, tomatoes, cabbage). This is less common in Ghana but is used on large commercial vegetable farms. Crop Maintenance Machinery These machines are used to care for the crop between planting and harvesting. Sprayers: Used to apply fertilisers, pesticides, or herbicides. Boom Sprayer: A tractor-mounted machine with long arms (booms) fitted with nozzles that spray liquid over a wide area. This ensures even application on large farms. Irrigation Systems: While not always "machinery" in the tractor sense, mechanised systems are crucial. Sprinklers: Devices that spray water over crops, simulating rainfall. They can be stationary or mobile. Drip Irrigation Systems: A network of pipes and tubes that deliver water directly to the base of each plant, conserving water. Harvesting Machinery These machines are used to gather mature crops from the field. Combine Harvester: An amazing machine that combines three separate operations into one: Reaping: Cutting the standing crop. Threshing: Separating the edible grain (e.g., maize kernels, rice grains) from the rest of the plant (stalks, chaff). Winnowing: Cleaning the grain by blowing away the lighter chaff. It is used for grain crops like maize, rice, and soybeans. Root Crop Harvesters: Specialised machines for harvesting crops like potatoes, yams, or cassava. They dig into the soil, lift the tubers, and separate them from the soil. C. Principles of Operation and Safety