Lesson Notes By Weeks and Term v4 - SHS 2
MODERN MECHAN ISED AGRICULTURE
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MODERN MECHAN ISED AGRICULTURE
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Subject: Agriculture
Class: SHS 2
Term: 1st Term
Week: 16
Grade code: 2.2.2.LI.3
Strand code: 2
Sub-strand code: 2
Content standard code: 2.2.2.CS.2
Indicator code: 2.2.2.LI.3
Theme: MODERN TECHNICAL AND MECHANISED AGRICULTURE
Subtheme: MODERN MECHAN ISED AGRICULTURE
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This lesson focuses on the practical skills needed to operate simple tools, implements, and machinery used during and after harvesting. In Ghana, a significant portion of the food we grow is lost between the farm and the market due to poor harvesting and post-harvest practices. By mastering the use of both traditional and modern tools, we can reduce this loss, work more efficiently, save time and energy, and ultimately improve food security and increase income for our farmers. This lesson moves from theory to practice, equipping you with the knowledge and skills to handle these essential agricultural tools safely and effectively.
A. Defining Key Terms Harvesting: The process of gathering mature crops from the fields. The method used depends on the type of crop. Post-Harvest Handling: The series of activities a crop undergoes from the moment it is harvested until it is consumed or processed. This includes threshing, drying, cleaning, sorting, storage, and transportation. Implement/Tool: A simple device held in the hand to perform a specific task (e.g., cutlass, sickle). Machinery: A more complex device with moving parts, often powered by an engine or electricity, designed to reduce human labour (e.g., corn mill, mechanical thresher). B. Categories of Harvest and Post-Harvest Implements and Machinery
We will explore these tools by categorizing them according to their function. For each, we will discuss its operation and safety. I. Harvesting Implements
These are used to gather the crops from the farm. Cutlass / Machete Description: A long, heavy knife with a single cutting edge. It is one of the most versatile tools on a Ghanaian farm. Crops: Used for harvesting cassava, yam, plantain, sugarcane, and for clearing weeds. Operation (for Cassava): Hold the cutlass handle firmly. Clear the area around the base of the cassava plant. Chop the cassava stem about 15-20 cm above the ground, leaving a "handle." Use the "handle" to pull and lever the tubers out of the ground. The soil may need to be loosened with the cutlass tip or a hoe first. Safety Precautions: Always maintain a secure footing before swinging. Ensure no one is standing close to you, especially in your swing path. Keep the blade sharp; a blunt blade requires more force and is more dangerous. When not in use, keep it in a sheath or a safe place. Sickle Description: A hand-held tool with a curved, crescent-shaped blade and a short handle. Crops: Ideal for harvesting cereals with stalks, like rice, wheat, and some grasses for animal feed. Operation (for Rice): With your non-dominant hand, grasp a bunch of rice stalks. With your dominant hand, hold the sickle. Place the inside curve of the blade against the base of the stalks you are holding. Pull the sickle firmly and swiftly towards your body in a cutting motion. Crucially, your other hand holding the stalks must be kept well above the cutting path. Safety Precautions: Always cut away from your legs and the hand holding the crop. Wear protective gloves to prevent cuts on your hands. Store with a blade cover or hang it securely. Go-to-Hell (Harvesting Knife/Sickle Pole) Description: A long wooden or bamboo pole with a sharp, curved blade attached to the end. Crops: Used for harvesting tree crops where the fruits are out of reach, such as cocoa pods, palm fruits, and mangoes. Operation (for Cocoa): Stand firmly on the ground, a safe distance from the tree trunk. Identify a ripe pod. Position the sharp hook of the blade around the stalk of the pod. Pull down firmly and sharply to sever the pod from the tree. Be ready to step away as the pod falls to avoid being hit. Safety Precautions: Ensure the blade is securely fastened to the pole. Be aware of your surroundings and other people before pulling. Wear a helmet or hard hat if possible to protect your head from falling pods. II. Post-Harvest Implements and Machinery
These are used after the crop has been brought from the farm. Threshing / Shelling Implements Threshing: Separating grain from the stalk/chaff. Shelling: Removing maize kernels from the cob. Manual Method (Flailing): Beating harvested rice or millet panicles with a stick on a hard surface or tarpaulin to release the grains. Hand-Cranked Maize Sheller (Simple Machine): Description: A small, cast-iron device mounted on a wooden stand. It has a rotating disc with teeth and a spring-loaded pressure plate. Operation: Mount the sheller securely to a bench or box. Take a dried maize cob and insert the tip into the opening. Turn the handle (crank) with one hand while pushing the cob through with the other. The rotating teeth will strip the kernels from the cob, which fall below. The empty cob exits from the other side. Benefits: Much faster than by hand, reduces thumb sores and blisters, and results in less grain damage. Drying Equipment Drying: Reducing the moisture content of the grain to a safe level (e.g., 12-14% for maize) for storage to prevent mould and insect infestation. Raised Platform / Tarpaulin: A simple method where grains are spread in a thin layer under the sun. They must be turned regularly for even drying. Solar Dryer (Simple Technology): Description: An enclosed structure, often made of a wooden frame covered with clear plastic sheeting. It has vents to allow air circulation. Operation Principle: The sun's rays pass through the plastic, heating the air and the grain inside. The heated air absorbs moisture from the grain. The warm, moist air is lighter and rises, exiting through the top vents. Cooler, drier air enters through the bottom vents, continuing the process. Benefits: Protects grain from rain, dust, and animals. Dries faster than open-sun drying because it traps more heat. Storage Structures Storage: Keeping harvested produce safe for future use, sale, or planting. Traditional Crib (for Maize): Description: A structure built with a raised platform, wooden poles for walls (with gaps for ventilation), and a thatched or zinc roof. Function: It allows air to circulate freely around the maize cobs, continuing the drying process and preventing mould. The raised platform and rodent guards (metal cones on the legs) protect against rats. Hermetic Storage Bags (e.g., PICS Bags): Description: An airtight storage technology consisting of two inner plastic liners and a tough outer woven sack. Operation Principle (The Science): Properly dried grain is placed inside the two liners. Each liner is twisted and tied securely to create an airtight seal. Any insects (like weevils) sealed inside with the grain will use up the limited oxygen through respiration. Once the oxygen is depleted, the insects suffocate and die, and their eggs cannot hatch. This prevents damage without using chemicals.