Chapter 3: Agriculture and the Environment Flashcards
Q: What are mineral particles in soil composed of?
A: Rock fragments and other inorganic substances.
Q: How are mineral particles formed?
A: Through physical, chemical, and biological weathering of parent rock.
Q: What does organic content in soil include?
A: Living plants, animals, microorganisms, and their dead remains.
Q: How does air enter the soil?
A: By diffusion.
Q: What role does water play in soil?
A: It is held in pore spaces and is available for plant growth.
Q: How does water enter the soil?
A: Through precipitation or irrigation.
Q: What is the size range and texture of sandy soil?
A: 2.0-0.02 mm, gritty.
Q: What factors affect the proportion of soil components?
A: Type of soil, management, local climatic conditions, and size of mineral particles
Q: What is the size range and texture of silty soil?
A: 0.02-0.002 mm, silky or soapy.
Q: What is the size range and texture of clay soil?
A: <0.002 mm, sticky when wet and hard when dry.
Q: What are the key functions of soil for plants?
A: Provides water, mineral nutrients, anchorage, and oxygen.
Q: What elements do plants require from soil?
A: Nitrogen, phosphorus, potassium, and other elements.
Q: How is nitrogen supplied to plants?
A: As nitrate ions (NO3-).
Q: How is phosphorus supplied to plants?
A: As phosphate ions (PO43-).
Q: How is potassium supplied to plants?
A: As potassium ions (K+).
Q: What is the role of earthworms in soil?
A: They break down vegetation, mix the soil, aerate it, and spread organic matter.
Q: What role do bacteria play in soil?
A: They work on organic matter, convert waste products to simple chemicals, and some convert nitrogen to nitrates.
Q: What role do fungi play in soil?
A: They feed on dead matter, digest woody items, and help plants take up nutrients.
Q: How does high organic matter benefit soil?
A: Increases water-holding capacity, air spaces, decomposers, and prevents nutrient loss.
Q: Compare sand and clay in terms of air spaces and drainage.
A: Sand has larger air spaces and drains well, clay has poor air spaces and drainage
Q: What factors influence soil pH?
A: Type of parent rock and pH of incoming water.
Q: Why might farmers adjust soil pH?
A: To either acidify or make it alkaline for better nutrient availability.
Q: What is subsistence agriculture?
A: Cultivation of food to meet the needs of farmers and their families.
Q: What is the capacity of soil drainage?
A: It should be medium—no water loss or surplus.
Q: What is commercial agriculture?
A: Cultivation of food with the main aim of selling for cash.
Q: What are examples of subsistence crops?
A: Wheat and rice.
Q: What are examples of commercial crops?
A: Tea, coffee, cocoa, sugarcane, cotton, rice, wheat, and corn.
Q: What is arable agriculture?
A: Production of plants for human consumption.
Q: What is pastoral agriculture?
A: Production of animals or animal-related products.
Q: What is mixed agriculture?
A: Farms that grow crops and rear animals.
Q: What is crop rotation?
A: Growing different types of plants in different plots each year.
Q: What benefit do legumes provide in crop rotation?
A: They have nitrogen-fixing bacteria in their root nodules.
Q: What are the advantages of crop rotation?
A: Reduces diseases and pests, maintains nutrient levels, and less waste.
Q: What are the types of fertilizers?
A: Organic and inorganic.
Q: What are the advantages of organic fertilizers?
A: Uses natural resources, supplies organic matter, and has minimal transportation costs.
Q: What are the disadvantages of organic fertilizers?
A: Unpleasant to handle, harder to transport, and variable in composition.
Q: What are the advantages of inorganic fertilizers?
A: Quick acting, easier to store, and meet specific needs.
Q: What is the purpose of irrigation?
A: To supply water to crops.
Q: What are the disadvantages of inorganic fertilizers?
A: Costly to manufacture, leach out in heavy rain, and potential for deficiency problems.
Q: What are common water application methods in irrigation?
A: Overhead sprinklers, clay pot irrigation, trickle drip system, and flood irrigation.
Q: What is the advantage of clay pot irrigation?
A: Simple technology and high efficiency.
Q: What is the main disadvantage of overhead sprinklers?
A: Water can evaporate quickly from leaves and soil.
Q: What is a disadvantage of clay pot irrigation?
A: Only suitable for permanent plants and has a large labour cost.
Q: What is the main advantage of the trickle drip system?
A: Water is used very efficiently.
Q: What is a disadvantage of the trickle drip system?
A: Expensive to install and complex to maintain.
Q: What is a disadvantage of flood irrigation?
A: Inefficient use of water and can damage soil structure.
Q: What are the main purposes of pesticides?
A: To control pests and diseases in crops.
Q: What are the advantages of herbicides?
A: Easier to manage, cheaper, and results are more predictable.
Q: What are herbicides used for?
A: Weed control.
How are crop diseases caused?
By fungi, bacteria, or viruses.
Q: What are alternatives to herbicides?
A: Hand weeding, hoeing, weed barriers, and flame guns.
What are insecticides used for?
Insect control.
What is a common method to control fungal crop diseases?
Using fungicides.
What is an alternative to insecticides?
Biological control using natural predators.
What are the advantages of biological control for pests?
No chemical residues and no impact of sprays.
What are the disadvantages of biological control for pests?
Not as instant as chemical control and predators may feed on unintended plants.
What is selective breeding?
Choosing parents with desired characteristics to breed offspring with those traits.
What is mechanisation in agriculture?
Using machinery to cultivate larger areas and reduce labour costs.
Q: What is a drawback of selective breeding?
A: It is a slow process with a less success rate.
Q: What is genetic modification?
A: Inserting DNA from one organism into another.
Q: What are some advantages of genetically modified organisms (GMOs)?
A: Increased disease resistance, nutritional value, and herbicide resistance.
Q: What are some disadvantages of GMOs?
A: Unknown health impacts, reduced biodiversity, and possible reduction in the gene pool.
Q: What is a greenhouse used for?
A: To manage the environment for optimal plant growth.
Q: How can temperature be increased in a greenhouse?
A: By operating a heating system.
Q: How can humidity be decreased in a greenhouse?
A: By using open roof ventilators
Q: What is the impact of overuse of herbicides and insecticides?
A: Development of resistance in pests and unintended environmental damage.
Q: What is salinization?
A: Increase in soil salt content due to irrigation.
Q: What is eutrophication?
A: Excess nutrients from fertilizers causing algae blooms and oxygen depletion in water bodies.
Q: What is soil capping?
A: When the surface of the soil becomes hard and difficult to cultivate.
Q: What is the purpose of terracing?
A: To prevent soil erosion on steep slopes by holding water and reducing run-off.
Q: What is contour ploughing?
A: Ploughing along the contours of the land to prevent soil erosion.
Q: What are bunds used for?
A: To hold back water and increase soil fertility.
