soil and food production Flashcards
2/11/25
What are the factors affecting world hunger?
- Unequal distribution of food
- decrease in arable land
- increasing population
- increasing poverty in developing countries
What are the layers of soil and their components?
O Horizon: Organic matter, decomposing leaves
A Horizon (Topsoil): Rich in minerals and nutrients
B Horizon (Subsoil): Accumulates leached materials from above
C Horizon (Parent Material): Weathered rock fragments
Bedrock: Solid rock beneath soil layers
Arrange soil particle sizes from largest to smallest.
Sand > Silt > Clay
How do you use a soil texture triangle?
Based on the percentage of sand, silt, and clay in the soil, it determines soil classification (e.g., loam, sandy clay, silty clay).
How does particle size affect permeability?
Larger particles (sand) = High permeability (drains quickly);
Smaller particles (clay) = Low permeability (retains water).
What are some soil tests and their importance?
pH Test: Determines acidity/alkalinity
Nutrient Test: Measures nitrogen, phosphorus, potassium (NPK)
Permeability Test: Assesses drainage capability
Texture: The percentage of sand, silt, and clay by weight it contains
What are the three steps of the Green Revolution?
1) Development of high-yield crop varieties
2) Increased use of chemical fertilizers and pesticides
3) Expansion of irrigation infrastructure
What are the advantages and disadvantages of CAFOs/feedlots?
Advantages: Efficient meat production, lower costs
Disadvantages: Pollution, ethical concerns, antibiotic resistance
What are the advantages and disadvantages of GMOs?
Advantages:
- Higher yields/grows faster
- Needs less pesticides
- improved nutrition
- Needs less fertilizer and water
- More resistant to insects/diseases
Disadvantages:
- Biodiversity loss
- unknown health effects
- Harmful toxins in food
- Lower nutrition
- Lower genetic diversity
What is the largest cause of soil erosion?
Moving Water: can carry away topsoil when there is inadequate vegetation cover or steep slopes on the land.
How can soil erosion be minimized in agriculture?
Cover crops, reduced tillage, windbreaks
What is desertification?
Desertification: Land degradation due to drought, deforestation
What is salinization?
Salt buildup from irrigation
What is waterlogging?
Excess water saturating soil, reducing oxygen availability
What is the difference between monoculture and polyculture?
Monoculture: Single crop cultivation
Polyculture: Multiple crops grown together
What are methods to control soil erosion?
Contour planting
Terracing
Strip cropping
Alley cropping
Shelterbelts
What are different types of farming?
Plantation Farming: Large-scale cash crops (e.g., bananas, coffee)
Subsistence Farming: Small-scale farming for local consumption
Industrialized Farming: Large-scale, mechanized production
Hydroponics: Growing plants in nutrient solutions
Aquaponics: Combining fish farming with hydroponics
What are the advantages and disadvantages of industrialized?
Advantages:
- High efficiency and productivity
- Large-scale food production
- Lower costs
- Consistent and uniform crop yields
- Use of technology (e.g., precision farming) to optimize resources
Disadvantages:
- High dependency on chemical fertilizers and pesticides
- Soil degradation and loss of biodiversity
- Pollution from runoff and emissions
- Increased antibiotic use in livestock leading to resistance
- Ethical concerns regarding animal welfare in factory farming
What are the advantages and disadvantages of organic farming?
Advantages:
- Sustainable
- avoids synthetic chemicals
- promotes soil health
Disadvantages:
- Lower yields
- higher costs
- labor-intensive
How is animal manure used in energy production?
a process called anaerobic digestion,
bacteria breaks down the organic matter in the manure to produce biogas (a mixture of methane and carbon dioxide)
can then be captured and used to generate electricity or heat on a farm by burning it in a generator or boiler;
the manure is converted into a renewable fuel source
Used in biogas production (methane) for energy
What are the advantages and disadvantages of synthetic pesticides?
Advantages:
- Protect crops
- increase yields
- Expand food supplies
- safe if used properly
- Works fast
Disadvantages:
- Harmful to ecosystems by killing pests’ natural enemies
- Pesticide resistance
Expensive for farmers
What is LD-50?
Measurement of a substance’s toxicity (dose that kills 50% of test subjects)
How is DDT an example of the boomerang effect?
It was accumulated in the food chain through biomagnification, harming predatory birds like eagles and falcons by weakening eggshells, leading to population declines
Traces of DDT were detected in human tissue, demonstrating how chemicals released into the environment can return and negatively impact human health
What was Rachel Carson’s contribution to environmental awareness?
Wrote Silent Spring
raising awareness about pesticide dangers (DDT)
