Lesson Notes By Weeks and Term v4 - SHS 3
AGRICULTURAL MACHINERI ES
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AGRICULTURAL MACHINERI ES
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Subject: Agricultural Science
Class: SHS 3
Term: 1st Term
Week: 16
Grade code: 3.1.3.LI.4
Strand code: 1
Sub-strand code: 3
Content standard code: 3.1.2.CS.2
Indicator code: 3.1.3.LI.4
Theme: NEW DAWN AGRICULTURE
Subtheme: AGRICULTURAL MACHINERI ES
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This lesson introduces the essential topic of agricultural machinery, a cornerstone of modern farming. In Ghana, where agriculture is the backbone of our economy, moving from traditional, labour-intensive methods using tools like the cutlass and hoe to modern mechanization is crucial for increasing food production, ensuring food security, and making farming a profitable business. We will explore the wide range of tools, implements, and machines used in agriculture, from the simple hand tools familiar in our local communities to the complex machines seen on large commercial farms.
This section breaks down the core content needed to understand agricultural machinery. A. Fundamental Definitions Agricultural Mechanization: This is the application of engineering principles and technology in agricultural production, including the use of tools, implements, and machines to improve the efficiency of human labour. It's not just about tractors; even using a well-designed wheelbarrow is a form of mechanization. Simple Farm Tools: These are simple, hand-held instruments powered by human energy. They are the most common tools in small-scale farming in Ghana. *Examples:* Cutlass, hoe (*asÉ”*), mattock (*adwuma*), pickaxe, shovel, hand trowel, sickle. Farm Implements: These are devices attached to a power source (like an animal or a tractor) to perform a specific task. They do not have their own engine. *Examples:* Plough, harrow, ridger, trailer. Farm Machinery: These are complex pieces of equipment, often with their own engine, designed for specific or multiple farm operations. *Examples:* Tractor, combine harvester, corn sheller, power tiller. B. Classification of Agricultural Machinery by Function
The most common way to classify farm machinery is based on the specific operation they perform on the farm. Tillage Implements (For Land Preparation) Tillage is the mechanical manipulation of soil to provide a suitable seedbed for crops. It is divided into primary and secondary tillage. Primary Tillage Implements: These are used for the initial, deep breaking and turning of soil. They are used on uncultivated land or after harvesting. Mouldboard Plough: Inverts the soil completely, burying weeds and crop residues, which then decompose to form humus. It is very effective in controlling weeds but not suitable for rocky or stumpy land. Disc Plough: Consists of a series of hardened steel discs. It is more suitable for Ghanaian conditions with hard, dry, rocky, or stumpy soils because the discs can roll over obstacles. It does not invert the soil as completely as the mouldboard plough. Secondary Tillage Implements: These are used after primary tillage to break down large soil clods, level the ground, and create a fine tilth (a well-prepared seedbed). Harrows: Used to break soil clods and smoothen the soil surface. *Types:* Disc harrow, Spike-tooth harrow. Ridgers: Used to create ridges and furrows. This is essential for crops like yam, cassava, and maize, as it helps with water management and earthing-up. Cultivators: Used for weed control between rows of growing crops and for stirring the soil. Planting/Sowing Machines These machines are designed to place seeds or seedlings into the soil with precision. Planter: Sows seeds in rows at specific distances from each other. Very common for crops like maize and beans. It ensures uniform plant population and spacing, which is difficult to achieve by hand. Seed Drill: Sows seeds in continuous furrows, not individually spaced. It is suitable for crops like rice and wheat. Transplanter: A machine that mechanizes the task of transplanting seedlings from a nursery to the main field. Used for rice and some vegetables. Crop Maintenance and Protection Machines These are used during the growth of the crop to ensure it is healthy and free from competition. Sprayers: Used to apply liquids like herbicides (to kill weeds), pesticides (to kill pests), and foliar fertilizers. *Knapsack Sprayer:* Carried on the back, manually operated. Very common among cocoa and vegetable farmers in Ghana. *Boom Sprayer:* A tractor-mounted sprayer with a long arm (boom) fitted with nozzles. It can cover a large area quickly. Fertilizer Spreader/Applicator: Distributes granular or liquid fertilizer evenly on the field. Harvesting Machines These machines are used to gather mature crops from the field. Reaper: A machine that cuts down grain crops like rice or wheat. Combine Harvester: This is a "combination" machine. It performs reaping (cutting), threshing (separating grain from the stalk), and winnowing (cleaning the grain) in one single operation. It is a massive time and labour saver for large-scale grain farms (e.g., maize farms in Afram Plains). Root Crop Harvester: Designed to dig up root and tuber crops like potatoes, cassava, or yams. Post-Harvest and Processing Machines These are used after the crop has been harvested to prepare it for storage or consumption. Thresher: Separates grains from the ear or pod (e.g., rice thresher). Sheller: Removes grains from the cob (e.g., a corn/maize sheller). This is much faster than shelling by hand. Grinding Mill: Grinds grains like maize, millet, or dried cassava into flour or powder. Gari Processing Machine: Includes a grater, press, and fryer used to process cassava into gari.
Guided Practice (With Solutions)
Question 1: A farmer at Nsawam has just cleared a one-hectare plot of land that has not been farmed for three years. The soil is hard and dry. Which primary tillage implement would you recommend he attaches to his tractor, a mouldboard plough or a disc plough? Justify your answer. Solution: Recommendation: A disc plough. Justification: The disc plough is more suitable for hard, dry, and potentially stumpy or rocky soil, which is common in land left fallow. The rotating discs can roll over obstacles that might damage a mouldboard plough. The mouldboard plough is more effective in soft, loamy soils without obstructions.