Agriculture and the environment

Topics

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Sample objectives

What this unit covers

• Soil composition: Students should be able to describe and explain what soils are made of, including the components such as mineral particles, organic matter (which includes living organisms like plants, animals, microorganisms, and their decomposed remains), as well as air and water. They should also understand the different particle sizes that make up soil, specifically sand, silt, and clay.
• Soils for plant growth: Students should be able to explain the role of soils in supporting plant growth, including aspects such as mineral ions (specifically nitrogen as nitrate ions, phosphorus as phosphate ions, and potassium as potassium ions), organic matter, pH levels, air content, water content, drainage, and the ease of cultivation. Additionally, they should be able to differentiate between sandy and clay soils.
• Agriculture types: Students should be able to explain the various categories of agriculture, including arable, pastoral, mixed, subsistence, and commercial types.
• Increasing agricultural yields: Students should be able to explain methods for enhancing agricultural production, including: crop rotation, the use of fertilizers, irrigation practices, pest management (through insecticides and biological methods), weed management (using herbicides), fungal management (with fungicides), mechanization, selective breeding of both animals and plants, the application of genetically modified organisms, and the use of controlled environments such as greenhouses and hydroponics.
• Impact of agriculture: Students should be able to outline and clarify how agricultural practices affect the environment and human populations, including issues such as excessive use of pesticides and herbicides, overapplication of fertilizers, poor irrigation management leading to salinization and waterlogging, overproduction and waste generation, depletion of mineral ions, soil erosion, and the replacement of food crops with cash crops.
• Causes and impacts of soil erosion: Understand and explain the factors leading to soil erosion and its consequences. This includes: identifying the reasons for soil erosion such as the clearing of vegetation due to excessive farming and grazing, as well as erosion caused by water and wind. Additionally, explain the effects of soil erosion, which encompass habitat loss, desertification, river silting, population displacement, and issues like malnutrition and famine.
• Managing soil erosion: Students should be able to outline and clarify methods for minimizing soil erosion, including techniques such as terracing, contour ploughing, constructing bunds, establishing wind breaks, preserving vegetation cover, enhancing soil structure through organic matter addition, and implementing practices like tree planting, mixed cropping, intercropping, and crop rotation.
• Sustainable agriculture: Students should be able to outline and clarify methods for sustainable agriculture, including the use of organic fertilizers (such as crop residues and manure), managed grazing techniques (like livestock rotation), crop rotation practices, and the implementation of pest-resistant and drought-resistant crop varieties. They should also understand the techniques of trickle drip irrigation and rainwater harvesting. Additionally, students are required to analyze a case study that illustrates a situation where agricultural practices have led to significant environmental damage, such as soil erosion, and discuss strategies for soil conservation.