APES_Chapter_9_-_Soil_Agriculture
Case Study: Bees to the Rescue
Pollinators' Role
Essential for pollinating flowering crops
More than 150 crops depend on pollinators
Decline of Pollinators
Loss of habitat and diverse flowering plants
Replacement with single-crop fields contributes to decline
Farmer Innovations
Lakhy Sran’s almond orchard incorporates wildflowers and clover
Aim to provide habitats and food for pollinators
Reduced Pesticide Use
Adoption of integrated pest management approaches
Resources & Services
Agriculture's Role
Fulfills basic daily needs: food, clothing (cotton)
Major environmental impacts necessitate sustainable practices
Natural Resources & Land Use
Definition of Agriculture
Raising crops and livestock for human consumption
Land Types
Cropland: land for food and fiber production
Rangeland/Pastureland: land for grazing livestock
Resource Requirements
Inputs: soil, sunlight, water, nutrients, pollinators
38% of Earth's land used for food and fiber production
Industrialization
Characteristics of Traditional Agriculture
Relied on human and animal muscle power
Sustenance level food production only
Transition to Industrial Agriculture
Mechanization and fossil fuel consumption
Increased irrigation, synthetic fertilizers, and pesticides enhanced yields
Monocultures vs. Polyculture
Industrial agriculture led to monoculture prevalence
Traditional polyculture included mixed crops
Impact of the Green Revolution
Introduced technology and crop varieties to developing nations
Increased yields but degraded soil and water resources
Green Revolution
Definition
Late 20th century agricultural transformation
Heavy use of fertilizers, pesticides, and irrigation increased yields
Key Figures
Norman Borlaug introduced disease-resistant wheat varieties,
Tripled wheat production in Mexico, applied practices in India and Pakistan
Sustainable Agriculture
Goals of Sustainable Agriculture
Maintain healthy soil, clean water, and vibrant pollinator populations
Emphasizes mimicking natural ecosystems
Knowledge Requirement
Understanding of soil, water, nutrients, and pollinators
Soil
Definition
Complex, plant-supporting system
Composed of disintegrated rock, organic matter, air, water, nutrients, microorganisms
Composition
Approximately 50% mineral, 5% organic matter, 45% pore space
Role of Soil for Plants
Provides nutrients, structure for rooting, medium for absorption
Mycorrhizae
Mutualistic fungi helping plants with water and nutrient absorption
Soil Formation
Process of Soil Formation
Initiated during primary succession
Parent material breaks down due to water, air, and organisms
Parent Material Definition
Base geological material (e.g., hardened lava, sediment)
Weathering Types
Physical: wind, rain, freeze/thaw cycles
Chemical: water or gases alter the rock chemically
Biological: living organisms contribute to soil formation
Importance of Humus
Partially decomposed organic matter critical for plant life
Influencing Factors for Weathering
Climate, organisms, topography, parent material, time
Renewal Rate of Soil
Soil is renewable but at a very slow rate
Soil Horizons Definition
Distinct layers resulting from movement and sorting of particles
Soil Profile Description
Cross-section showing depth and composition changes
Leaching Impact
Minerals can be dissolved and transported downward
Structure of Soil Profile
O Horizon: organic litter layer
A Horizon: topsoil, nutrient-rich
B Horizon: subsoil, accumulates minerals and organic matter
C Horizon: weathered parent material
R Horizon: bedrock or parent material
Soil Quality
Color Indicators
Dark soils signify organic-rich; pale suggests leaching
Soil Structure
Clumpiness is ideal; compaction inhibits growth
pH Preference
Intermediate pH levels are best for plant health
Soil Texture
Characteristics of Soils
Clay: limited pore spaces, sticky, less drainage
Sandy: quick drainage, may require more irrigation
Loam: ideal mix of clay, silt, and sand for agriculture
Irrigation
Comparison of Soil Productivity
Amazon rainforest case shows lower productivity than regions like Iowa
Swidden Agriculture
Tropical practice of shifting cultivation and slash-and-burn techniques
Definition and Imperative
Artificial water provision beyond rainfall
Critical for water-intensive crops and dry climates
Comprises 70% of freshwater withdrawals
Issues with Water Application
Waterlogging and salinization concepts explored
Solutions for salinity issues through flushing or salt-tolerant plants
Irrigation Efficiency
Typically, just 40% of water used by plants
Benefits of drip irrigation in reducing waste
Overview of conventional irrigation methods and their effectiveness
Fertilizers
Types of Fertilizers
Inorganic: synthetic or mined materials
Organic: derived from biological origins
Compost: decomposed organic materials
Environmental Impact of Overapplication
Nutrient runoff can cause broader ecological issues
Definition of Precision Agriculture
Use of technology for monitoring crop resource needs
Pollination
Pollination Defined
Fertilization of female flowers by male pollen
Crucial role of pollinators in agriculture
Crisis in Wild Pollinators
Factors contributing to the declining populations
Impact of habitat loss and pesticide use
Threats to Honeybee Populations
Colony Collapse Disorder overview
Risks associated with specific pesticides, e.g., neonicotinoids
Strategies for Supporting Pollinator Populations
Establishing diverse habitats and reducing chemical usage
Monocultures
Dangers of Reduced Crop Diversity
Over-reliance on a few crops increases vulnerability
Landraces
Importance of preserving local crop varieties for genetic diversity
Seed Banks' Role
Preservation of seeds as insurance against agricultural loss
Conserving Land and Soil
Challenges to Key Agricultural Resources
Necessity for conservation to prevent further degradation
Land Degradation
Definition and Negative Outcomes
Highlights issues such as erosion and pollution
Soil Degradation
Causes and Consequences
Linkages to human activities like deforestation and cropland use
Erosion
Definition and Dynamics of Erosion
Mechanisms of erosion exacerbated by agricultural practices
Human Contributions to Erosion
Over-cultivation, overgrazing, and deforestation impacts
Desertification Description
Loss of land productivity risks food security
The Dust Bowl
Historical Context of the Dust Bowl
Impact of agricultural practices and severe drought
Extent of Topsoil Loss
Significant erosion in affected areas
Government Response
Soil Conservation Act led to establishing conservation services
Soil Conservation Strategies
Overview of techniques to prevent soil erosion
Crop Rotation
Benefits of Crop Rotation
Enhancing soil fertility, pest control, and erosion prevention
Contour Farming
Contour Farming Technique
Reduces runoff and soil loss on sloped terrain
Terracing
Terracing Methodology
Efficiently farms hilly lands and retains water
Intercropping
Benefits of Intercropping
Reduces erosion, pest vulnerability, and enriches soil
Shelterbelts
Role of Shelterbelts
Provide windbreaks and improve soil conservation
Conservation Tillage
Benefits of Reduced Tilling
Protects soil and retains moisture for crops
Overgrazing
Effects of Overgrazing
Soil vulnerability increases under excessive livestock pressure
Positive Feedback Loop
Erosion exacerbates plant growth challenges
Subsidies
Role of Subsidies in Agriculture
Financial aid creates dependability but fosters unsustainable farming
Policy
Overview of Farm Bill
Periodic legislation impacting agricultural practices and funding
Environmental Benefits Index in Farming
Assessment criteria for farmer contracts aimed at conservation activities.