Lesson Notes By Weeks and Term v4 - SHS 2
MODERN MECHAN ISED AGRICULTURE
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
MODERN MECHAN ISED AGRICULTURE
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Subject: Agriculture
Class: SHS 2
Term: 1st Term
Week: 11
Grade code: 2.2.2.LI.2
Strand code: 2
Sub-strand code: 2
Content standard code: 2.2.2.CS.1
Indicator code: 2.2.2.LI.2
Theme: MODERN TECHNICAL AND MECHANISED AGRICULTURE
Subtheme: MODERN MECHAN ISED AGRICULTURE
This page supports the lesson note with a companion video and a short classroom-ready summary.
For class groups and homework, share this lesson page so learners also get the summary, objectives, and full lesson context.
In Ghana, our agriculture is heavily dependent on rainfall. We have a rainy season when there is plenty of water, and a long dry season (Harmattan) when farming becomes very difficult or impossible in many areas. This reliance on seasonal rain limits our ability to produce food all year round. Modern mechanised agriculture provides a solution through irrigation (supplying water to crops) and drainage (removing excess water). By managing water effectively, we can increase food production, create jobs, and improve our national food security. This lesson explores the methods and importance of these two critical water management systems.
A. What is Irrigation?
Definition: Irrigation is the artificial application of water to land or soil to assist in the growing of crops. It is used to supplement rainfall, especially during periods of drought or in areas with low rainfall, like the Savannah regions of Ghana. Essentially, irrigation is "watering the farm" in a controlled way.
Why is Irrigation Necessary in Ghana? Erratic Rainfall: The rainy season can be unpredictable. Sometimes it starts late, ends early, or has long dry spells in between. Dry Season Farming: The northern parts of Ghana have a single, long dry season. Irrigation allows farmers to cultivate crops like tomatoes, onions, and pepper during this period, providing year-round income. Growing Specific Crops: Some crops, like rice, require large and consistent amounts of water that rainfall alone may not provide. B. Methods of Irrigation
Irrigation methods can be broadly grouped into three categories: Surface, Sprinkler, and Drip/Micro-irrigation. Surface Irrigation This is where water flows over the soil surface to reach the crops. It is the oldest and most common method in Ghana, especially in government-led schemes like Tono and Vea. a) Basin / Flood Irrigation How it works: The field is divided into small, level basins or plots surrounded by bunds (small earth walls). Water is allowed to flood the entire basin to a certain depth. Suitability: Best for flat land and crops that can withstand standing water, like rice. It is widely used in the rice paddies of the Volta and Northern regions. Advantages: Low initial cost; simple technology. Disadvantages: Wastes a lot of water through evaporation and runoff; can lead to waterlogging if not managed well. b) Furrow Irrigation How it works: Small, parallel channels called "furrows" are dug between rows of crops. Water is directed into these furrows and it seeps sideways into the soil to water the plant roots. Suitability: Excellent for row crops like maize, tomatoes, okra, and groundnuts. The ridges where crops are planted remain dry. Advantages: More water-efficient than basin irrigation; less risk of water touching the plant stems, which can cause diseases. Disadvantages: Requires a gentle, uniform slope; can cause soil erosion if the water flow is too fast. c) Border Irrigation How it works: The land is divided into long, parallel strips (borders) separated by low ridges. A sheet of water flows down the slope of the strip, irrigating the crops as it moves. Suitability: Good for close-growing crops like wheat or fodder grasses. Advantages: Relatively simple to operate. Disadvantages: Requires very level land; less common in small-scale Ghanaian farming. Sprinkler Irrigation This method mimics natural rainfall. Water is pumped through pipes and sprayed into the air through rotating nozzles (sprinklers), falling onto the crops like rain. How it works: A pump provides pressure to move water through a network of main pipes and smaller lateral pipes. Sprinkler heads are attached to the lateral pipes. Suitability: Very good for sandy soils that absorb water quickly. Can be used on uneven or steep land where surface irrigation would cause erosion. Ideal for vegetables like cabbage, lettuce, and carrots. Advantages: High water efficiency (less wastage); uniform application of water; fertilizers and pesticides can be applied through the system (fertigation). Disadvantages: High initial cost (pumps, pipes, sprinklers); operation can be affected by strong winds; water on leaves can sometimes encourage fungal diseases. Drip / Micro-irrigation This is the most advanced and water-efficient method. Water is delivered slowly and directly to the root zone of each plant. How it works: Water flows through a network of plastic pipes and is released through small outlets called "emitters" or "drippers" located near the base of each plant. Suitability: Ideal for high-value crops like greenhouse vegetables, tree crops (mango, citrus), and in areas where water is very scarce. Advantages: Highest water efficiency (up to 95%); minimises weed growth as only the crop area is watered; reduces soil erosion and nutrient runoff. Disadvantages: Very high initial cost; emitters can easily get clogged by sand or dirt, requiring good water filtration. C. What is Drainage?