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: 8
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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Welcome, students. Today, we delve into the exciting world of agricultural machinery. Think about the food you eat every day – the banku, kenkey, rice, and yam. For Ghana to produce enough of this food to feed everyone and even export, farmers cannot rely solely on the cutlass and hoe. This is where agricultural machinery comes in. It represents the shift from subsistence (small-scale) farming to commercial (large-scale) agriculture. Understanding these machines is crucial for anyone interested in modern farming, food security, and the business of agriculture in Ghana.
A. What is Agricultural Machinery? Simple Farm Tools: These are simple, hand-held instruments that rely on human power. Examples: cutlass, hoe, sickle, hand trowel, mattock, pickaxe. They are suitable for small gardens or subsistence farms. Agricultural Machinery: These are complex pieces of equipment, often powered by an engine (or sometimes animals), designed to perform agricultural tasks efficiently on a larger scale. They reduce human labour, save time, and increase the area of land that can be cultivated.
The main source of power for most heavy machinery is the Tractor. The tractor is the prime mover on the farm; it pulls, pushes, or powers other machines (called implements or attachments).
B. Classification of Agricultural Machinery Based on Use
We can classify machinery based on the specific stage of crop production they are used for. This is the most logical way to understand their roles on the farm. Tillage Machinery (Land Preparation) Tillage is the process of preparing the soil for planting. It is divided into two stages: Primary Tillage: This is the first, deep breaking and turning of the soil. It is done to break up compact soil, bury weeds and crop residues, and improve aeration and water infiltration. Machine Example 1: Plough (or Plow) Function: The plough is the main primary tillage implement. It cuts, lifts, and turns the soil over in slices called "furrow slices." Types: Mouldboard Plough: The most common type. Its curved board (the mouldboard) effectively turns the soil over. Ideal for burying heavy vegetation. Disc Plough: Consists of large, rotating concave discs. It is better for hard, dry, or sticky soils and can roll over obstacles like rocks and stumps. Secondary Tillage: This follows primary tillage. It involves breaking down the large soil clods left by the plough into a finer, more level seedbed suitable for planting. Machine Example 2: Harrow Function: To break up soil clods, level the field, and remove weeds. It creates a fine tilth for seed germination. Types: Disc Harrow: Uses smaller discs than a disc plough to chop up clods. Spike-tooth Harrow: A frame with rigid spikes that are dragged through the soil to level it and break smaller lumps. Machine Example 3: Ridger Function: Used to make ridges and furrows. This is very important for crops like yam, cassava, and maize, as it helps with water management and earthing-up. It is typically used after harrowing. Planting Machinery These machines are designed to place seeds or seedlings into the prepared soil accurately and quickly. Machine Example 4: Planter / Seeder Function: To sow seeds in rows at a specific depth and spacing. This ensures a uniform plant population, which makes subsequent operations like weeding and harvesting easier. Types: Row-crop Planter: Sows seeds like maize, beans, and soybeans in precise rows. Grain Drill: Sows seeds for crops like rice and wheat in narrow, closely spaced rows. Crop Maintenance and Protection Machinery These are used after planting but before harvesting to care for the growing crops. Machine Example 5: Sprayer Function: To apply liquids like herbicides (for weed control), pesticides (for pest control), fungicides (for disease control), or liquid fertilizers to the crops. Types: Boom Sprayer: A tractor-mounted machine with a long boom (arm) fitted with many nozzles. It can cover a wide area quickly and is used on large commercial farms. Knapsack Sprayer: Carried on the back of the operator. Can be manual or motorized. Common on smaller farms in Ghana. Machine Example 6: Irrigator Function: To supply water to crops artificially, especially during the dry season. Types: Sprinklers (which spray water like rain) and Drip irrigation systems (which deliver water directly to the plant roots). While the pipes are infrastructure, the pumps that power them are machinery. Harvesting and Post-Harvest Machinery These machines are used to gather mature crops from the field and prepare them for storage or sale. Machine Example 7: Combine Harvester Function: A complex, self-propelled machine that performs multiple harvesting operations in one pass – reaping (cutting the crop), threshing (separating the grain from the stalk), and winnowing (cleaning the grain). It is a huge time and labour saver for grain crops like rice, maize, and soybeans. Machine Example 8: Sheller / Thresher Function: These are simpler, often stationary machines used after manual harvesting. Maize Sheller: Removes maize kernels from the cob. Rice Thresher: Separates rice grains from the panicle (stalk).