Weathering and Soil Microbes

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Questions and Answers

What are the three forms of weathering?

Physical, Chemical, Biological (correct)

Mechanical, Chemical, Biological

Physical, Thermal, Biological

Biological, Chemical, Structural

Which mechanism is NOT an enhancement of plant growth by microorganisms?

Repelling pathogenic microbes

Manipulating hormonal signaling

Increasing bioavailability of nutrients

Decreasing soil pH (correct)

Which of the following is NOT a benefit of soil microbes?

Contributing to decomposition

Increasing soil salinity (correct)

Improving soil structure

Protecting plants from pathogens

How do soils function in the carbon cycle?

Soils store more carbon than the atmosphere Signup and view all the answers

Which of the following is NOT considered a soil threat?

Draining wetlands Signup and view all the answers

What are the major technological advances defining modern agriculture?

Development of irrigation systems, synthetic fertilizers, synthetic pesticides Signup and view all the answers

Which of the following is an example of water contamination from modern agricultural practices?

Fertilizer runoff leading to eutrophication Signup and view all the answers

What consequence arises from soil compaction in agriculture?

Reduced soil aeration Signup and view all the answers

What is the main benefit of aquaponics compared to traditional farming?

Uses significantly less water and produces more food. Signup and view all the answers

Which of the following describes a core principle of Integrated Pest Management (IPM)?

Employing cultural practices and biological controls before using pesticides. Signup and view all the answers

What is a significant challenge associated with aquaponics systems?

It demands substantial expertise in aquaculture and hydroponics management. Signup and view all the answers

How does composting contribute to environmental sustainability?

Enhances soil structure and reduces landfill waste. Signup and view all the answers

What role do trees and shrubs play in agroforestry?

They enhance biodiversity and sequester carbon. Signup and view all the answers

Which of the following statements about IPM is true?

It has successfully reduced pesticide use in several countries. Signup and view all the answers

Which method has cities like San Francisco implemented to enhance sustainability?

Implementing large-scale composting initiatives. Signup and view all the answers

What is a primary ecological benefit of agroforestry systems?

Sequesters carbon and enhances biodiversity. Signup and view all the answers

What is the main benefit of using conservation tillage?

Reduces soil disturbance and enhances moisture retention Signup and view all the answers

Which practice is specifically designed to mimic natural grazing patterns?

Mob grazing Signup and view all the answers

What is a significant challenge associated with mob grazing?

Careful planning to avoid overgrazing Signup and view all the answers

How much of the land did hedgerows sequester carbon in California's tomato fields?

6% of the land Signup and view all the answers

What has been the trend in global freshwater use over the last century?

It has increased sixfold Signup and view all the answers

What is one of the main driving forces behind the increase in global freshwater use?

Improved living standards Signup and view all the answers

What is a watershed also known as?

Drainage basin Signup and view all the answers

Which practice helps in reducing soil erosion while providing habitat for wildlife?

Conservation tillage Signup and view all the answers

What is a consequence of excessive groundwater pumping?

Wells may dry up Signup and view all the answers

Which of the following is NOT a principle for community governance of common goods?

Limitations on Autonomy Signup and view all the answers

What characterizes the tragedy of the commons?

Overexploitation of a shared resource Signup and view all the answers

Which issue is related to funding shortages in water management?

Insufficient investment in regulation Signup and view all the answers

What is a key interconnection of the Nexus approach?

Water management requires energy Signup and view all the answers

What defines the common good in resource systems?

Subtraction of resources due to consumption Signup and view all the answers

Which of the following is NOT an attribute for managing common goods?

Unlimited exploitation Signup and view all the answers

What causes land subsidence in water management?

Loss of soil stability Signup and view all the answers

Study Notes

Weathering

Weathering is the gradual breakdown of rocks into soil.
Three types of weathering exist:
- Physical Weathering: Breakdown by mechanical forces (temperature changes, abrasion, frost).
- Chemical Weathering: Breakdown by chemical reactions (water, air, other chemicals reacting with minerals).
- Biological Weathering: Breakdown by living organisms (plant roots, burrowing animals).

Microorganisms and Plant Growth

Microorganisms boost plant growth through:
- Manipulating plant hormones for increased growth.
- Preventing plant diseases and pathogens.
- Making nutrients more readily available to plants.

Soil Microbes Benefits

Improved soil structure.
Enhanced nutrient availability for plants.
Protection of plants from pathogens.
Contribution to humus formation (decomposition process).

Soil and the Carbon Cycle

Soil acts as a significant carbon sink, holding more carbon than the atmosphere.
Carbon enters the soil through photosynthesis and organic matter decay.
Carbon can be lost through respiration and oxidation.
Healthy soil management can store more carbon and mitigate greenhouse gases.

Soil Threats

Deforestation (soil erosion, loss of fertility).
Salinization (salt accumulation, reduced productivity).
Soil compaction (reduced aeration and water infiltration).
Erosion (loss of topsoil by wind or water).

Modern Agriculture Technological Advances

Irrigation systems
Synthetic fertilizers
Synthetic pesticides

Natural Capital Degradation from Modern Agriculture

Soil Degradation:
- Loss of organic matter
- Soil compaction
Water Contamination:
- Fertilizer runoff (eutrophication)
- Pesticide contamination of groundwater
Biodiversity Loss:
- Decline in pollinator populations
- Habitat destruction (monocultures)
Climate Change Contribution:
- Increased greenhouse gas emissions from fertilizers.
- Carbon release from soil degradation

Aquaponics

Sustainable agricultural system combining aquaculture (fish farming) and hydroponics (soilless plant cultivation).
Symbiotic system: fish waste provides nutrients for plants, and plants filter water for fish.
Highly water-efficient (1/6th of traditional farming water use), producing more food per acre.

Integrated Pest Management (IPM)

Ecosystem-based strategy for pest management with minimal environmental impact.
Integrates biological controls, cultural practices, and precise chemical use.
Reduces long-term costs and environmental harm (e.g., pesticide use reduction by >50% in some countries).

Composting

Aerobic decomposition of organic waste to create nutrient-rich soil amendments.
Reduces landfill waste and methane emissions while improving soil structure, water retention, fertility and carbon storage.

Agroforestry

Integrates trees and shrubs with crops or livestock.
Enhances biodiversity, reduces erosion minimizes chemicals and sequesters carbon through deeper root systems and longer-term biomass storage.

Conservation Tillage

Reduces soil disturbance by leaving residues on the soil surface.
Improved soil health (carbon sequestration, reduced erosion, improved moisture retention).

Mob Grazing

Mimics natural grazing patterns for balanced manure distribution, deeper root growth, increased plant diversity, and drought resilience.

Watersheds

Land area where surface runoff drains into a specific water body (stream, lake, wetland).

Freshwater Use Evolution

Global freshwater use has increased sixfold over the past century.
Key driving forces include population growth, improved living standards, dietary shifts (increased meat consumption), and expansion of irrigated agriculture.

Groundwater Depletion Consequences

Lowering the water table.
Decline in surface water.
Increased costs.
Saltwater intrusion.
Land subsidence.

Common Good

Resource system (e.g., water) that exhibits subtractability and difficulty in exclusion.

Tragedy of the Commons

Over-exploitation of a shared resource due to a lack of coordinated management.

Community Governance Principles

Shared Vision
Self-Organization and Conflict Resolution
Community Autonomy

Community Governance Attributes

Resource Renewal
Monitoring Mechanisms
Predictability

Water Management Issues

Growing demand across sectors (balancing competing uses).
Extension of rules and usage rights (clarifying regulatory frameworks).

Nexus Approach

Addresses interlinkages among water, energy, and food systems.
Highlights scarcity of resources and need for coordinated management to avoid trade-offs that compromise sustainability.

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Description

This quiz covers the process of weathering and its impact on soil formation. It delves into the roles of microorganisms in enhancing plant growth and overall soil health. Additionally, it discusses the importance of soil in the carbon cycle, highlighting its role as a carbon sink.