Lesson Notes By Weeks and Term v4 - SHS 2
MODERN TECHNICAL AGRICULTURE
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MODERN TECHNICAL AGRICULTURE
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Subject: Agriculture
Class: SHS 2
Term: 1st Term
Week: 8
Grade code: 2.2.1.LI.2
Strand code: 2
Sub-strand code: 1
Content standard code: 2.2.1.CS.1
Indicator code: 2.2.1.LI.2
Theme: MODERN TECHNICAL AND MECHANISED AGRICULTURE
Subtheme: MODERN TECHNICAL AGRICULTURE
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This lesson introduces the essential concepts of surveying and mapping in modern agriculture. In Ghana, land is our most valuable agricultural resource. Knowing its exact size, shape, and features is crucial for everything from preventing disputes with neighbours over the boundary of a cocoa farm to planning an efficient irrigation system for a vegetable farm in the dry season. This lesson will move beyond traditional estimation methods and explore the modern instruments that allow farmers to be more precise, efficient, and profitable. Understanding these tools is the first step towards practicing agriculture as a modern, technical business.
A. Fundamental Definitions Surveying: This is the science and art of determining the precise position of points and the distances and angles between them on a piece of land. Think of it as taking the measurements of the farm. We measure its length, width, boundaries, and the location of features like hills, streams, or large trees. Mapping: This is the process of using the data collected during surveying to create a visual representation (a map or a plan) of the land. Think of it as drawing the plan of the farm to scale using the measurements taken. A farm map is like a blueprint for the farm.
Analogy: Imagine a tailor. Surveying is like the tailor taking your measurements (chest, waist, arm length). Mapping is like the tailor drawing the pattern on the cloth before cutting. Without accurate measurements, the final dress or suit will not fit well. Similarly, without an accurate survey, farm plans will be ineffective. B. Why is Surveying Important in Ghanaian Agriculture? Determining Farm Size: It allows a farmer to know the exact acreage or hectares of their land. This is vital for calculating the correct amount of seeds, fertilizers, and pesticides to buy, preventing waste or under-application. Farm Planning and Layout: A good survey helps in planning the layout of the farm. This includes where to place crops, buildings (like a poultry house), irrigation channels, roads, and fences for maximum efficiency. Land Title and Security: A certified survey plan (often called a site plan or indenture) is required to secure legal title to land from the Lands Commission. This prevents land disputes and allows the farmer to use the land as collateral for a loan from a bank like the Agricultural Development Bank (ADB). Soil and Water Conservation: Surveying helps to identify the slope (gradient) of the land. This information is used to plan soil conservation structures like contours, terraces, and check dams to prevent soil erosion, especially in hilly areas of the Eastern or Volta Regions. C. Common Survey and Mapping Instruments and Their Uses
Here are some of the key instruments used in agricultural surveying, from simple tools to modern technology. Measuring Tape Description: A long, flexible strip of fibreglass, steel, or cloth marked with units of length (e.g., metres, feet). They come in various lengths, typically 30m, 50m, or 100m. Function: Measures linear (straight-line) distances between two points. Use in Agriculture: Measuring the length and breadth of a small farm plot to calculate its area. Setting out the spacing between rows for planting crops like maize or yam. Measuring the length required for fencing a livestock kraal or vegetable garden. Ranging Poles Description: Tall, straight poles (usually 2-3 metres long), painted in alternating bands of bright colours like red and white for visibility over long distances. They have a pointed metal tip to stick into the ground. Function: To mark the position of survey stations and to ensure that measurements are being taken in a straight line. Use in Agriculture: Used together with a measuring tape to measure the long boundary of a farm in a straight line. You place one at the start, one at the end, and others in between to guide the measurement process. Surveyor's Arrows or Pins Description: Short metal spikes (about 30-40 cm long) with a brightly coloured loop at the top. Function: Used to mark temporary points on the ground during a measurement exercise, especially when the distance is longer than the tape. Use in Agriculture: When measuring a 150m boundary with a 50m tape, an arrow is placed at the end of each 50m segment to mark the spot before moving the tape forward. Prismatic Compass Description: A handheld device with a magnetic needle that always points to the magnetic north. It has a prism and a sighting vane which allows the user to read a bearing (direction or angle relative to north) while looking at a distant object. Function: To measure bearings or directions. A bearing is an angle measured clockwise from the North. Use in Agriculture: To determine the orientation of the farm (e.g., which way the boundaries run). Used in compass surveying to map out the boundaries of an irregularly shaped farm by measuring the length and bearing of each boundary line. Theodolite / Total Station Description: A more complex instrument mounted on a tripod. A theodolite measures horizontal and vertical angles with high precision. A Total Station is a modern, electronic version that also measures distances electronically. Function: Precise measurement of horizontal and vertical angles and distances. Use in Agriculture: Used by professional surveyors for large-scale farm projects. Essential for planning complex irrigation and drainage systems that rely on gravity and precise slopes. Used to create highly accurate maps needed for engineering works on a farm (e.g., dam construction). Handheld GPS (Global Positioning System) Receiver Description: An electronic device that receives signals from satellites orbiting the Earth to determine the user's exact location (latitude, longitude, and altitude) on the globe. Function: To determine and record geographic coordinates of points on the farm. Use in Agriculture: Farm Mapping: A farmer can walk the boundary of their farm with a GPS device to quickly and accurately map it. COCOBOD uses this to map cocoa farms in Ghana. Area Calculation: The device can automatically calculate the area of the land enclosed by the recorded points. Precision Farming: Used to guide tractors for precise ploughing, planting, and application of fertilizer, reducing overlap and saving costs. Drones (Unmanned Aerial Vehicles - UAVs) Description: An aircraft without a human pilot on board, controlled from the ground. For surveying, they are equipped with high-resolution cameras. Function: To capture aerial images of the farm from above. Use in Agriculture: Rapid Mapping: A drone can map a very large farm (e.g., a commercial rice or pineapple plantation) in a fraction of the time it would take on foot. Crop Health Monitoring: Special cameras on drones can detect crop stress, pest attacks, or nutrient deficiencies before they are visible to the human eye. Creating 3D Models: The images can be used to create detailed 3D models of the farm, which are useful for planning drainage and irrigation.
Guided Practice (With Solutions)