Soil systems, terrestrial food production

Soil Systems and Terrestrial Food Production

Components of Soil Systems

Soil systems are complex and dynamic, consisting of various interconnected components. These include:

1. Storages: Soil acts as a storage for water, nutrients, organic matter, and minerals. For example, clay particles in soil can hold onto nutrients like potassium and calcium.
2. Inputs: Elements entering the soil system, such as organic matter from dead plants and animals, or fertilizers added by farmers.
3. Outputs: Materials leaving the soil system, like nutrients taken up by plants or lost through leaching.
4. Flows: Movement of materials within the soil system, such as water percolating through soil layers.
5. Transformations: Chemical and biological processes that change the form of materials in soil, like the decomposition of organic matter by microorganisms.

Note

Understanding soil as a system helps in managing it sustainably for food production.

Soil Profile Structure and Horizons

Soil profiles typically consist of distinct layers called horizons:

1. O horizon: The topmost layer, composed of organic matter like leaf litter.
2. A horizon: Also known as topsoil, rich in organic matter and nutrients.
3. B horizon: Subsoil, where materials leached from above accumulate.
4. C horizon: Partially weathered parent material.
5. R horizon: Bedrock.

Example

In a forest soil, you might find:

• O horizon: 5 cm of leaf litter

• A horizon: 15 cm of dark, organic-rich soil

• B horizon: 30 cm of reddish-brown clay-enriched soil

• C horizon: 50 cm of weathered rock fragments

• R horizon: Solid bedrock

Properties of Different Soil Types

1. Sandy soil:
   • Large particles
   • Good drainage
   • Poor nutrient retention
   • Warms quickly in spring
2. Clay soil:
   • Small particles
   • Poor drainage
   • High nutrient retention
   • Slow to warm in spring
3. Loam soil:
   • Mixture of sand, silt, and clay
   • Balanced drainage and nutrient retention
   • Ideal for most crops

Tip

Loam soil is often considered the best for agriculture due to its balanced properties.

Soil as an Ecosystem

Soil is a living system containing:

1. Microorganisms: Bacteria, fungi, and archaea that decompose organic matter and cycle nutrients.
2. Mesofauna: Smaller soil animals like nematodes and mites.
3. Macrofauna: Larger soil animals such as earthworms and insects.

These organisms interact with each other and the physical environment, creating a complex ecosystem that supports plant growth.

Terrestrial Food Production Systems and Food Choices

Factors Influencing Sustainability of Food Production Systems

1. Resource use efficiency: How effectively water, energy, and nutrients are used.
2. Environmental impact: Effects on biodiversity, soil health, and water quality.
3. Economic viability: Profitability and long-term economic sustainability.
4. Social acceptability: Cultural appropriateness and community support.
5. Climate resilience: Ability to withstand and adapt to changing climate conditions.

Comparing Different Food Production Systems

1. Intensive industrial agriculture:
   • High inputs (fertilizers, pesticides)
   • High outputs
   • Significant environmental impacts
   • Economically efficient at large scales
2. Organic farming:
   • Lower chemical inputs
   • Generally lower yields
   • Reduced environmental impact
   • Often more labor-intensive
3. Agroforestry:
   • Combines trees and crops/livestock
   • Diverse outputs
   • Enhanced ecosystem services
   • Requires long-term planning

Example

Comparing wheat production:

• Industrial farm: 8 tons/hectare, high pesticide use

• Organic farm: 6 tons/hectare, no synthetic pesticides

• Agroforestry: 5 tons/hectare wheat + timber and fruit crops

Strategies to Increase Sustainability in Food Production

1. Precision agriculture: Using technology to optimize resource use.
2. Crop rotation: Alternating crops to maintain soil health.
3. Integrated pest management: Combining biological, cultural, and chemical pest control methods.
4. Water conservation: Efficient irrigation systems and drought-resistant crops.
5. Agroecology: Applying ecological principles to agricultural systems.

Note

Sustainable food production often involves combining multiple strategies tailored to local conditions.

Links Between Sociocultural Systems and Food Production

1. Cultural preferences: Influencing crop choices and farming methods.
2. Traditional knowledge: Incorporating local wisdom into farming practices.
3. Land tenure systems: Affecting farmers' ability to invest in long-term sustainability.
4. Gender roles: Impacting labor distribution and decision-making in agriculture.
5. Urbanization: Changing food demand and agricultural land use.

Issues Around Food Supply, Distribution, and Waste

1. Food security: Ensuring sufficient, safe, and nutritious food for all.
2. Food deserts: Areas with limited access to fresh, healthy food.
3. Food waste: Approximately 1/3 of food produced globally is wasted.
4. Supply chain inefficiencies: Leading to losses during transportation and storage.
5. Climate change impacts: Affecting crop yields and distribution patterns.

Common Mistake

Many people assume that increasing food production alone will solve hunger issues. However, improving distribution and reducing waste are equally important.

Soil Degradation and Conservation

Soil Ecosystem Succession and Fertility

Soil fertility develops over time through:

1. Primary succession: Soil formation on bare rock.
2. Secondary succession: Recovery of disturbed soil.
3. Nutrient cycling: Continuous movement of nutrients between soil and organisms.
4. Organic matter accumulation: Building soil structure and nutrient reserves.

Human Activities that Reduce Soil Fertility

1. Overgrazing: Removing protective vegetation cover.
2. Monoculture: Depleting specific nutrients and reducing biodiversity.
3. Excessive tillage: Disrupting soil structure and accelerating organic matter loss.
4. Chemical fertilizer overuse: Altering soil pH and microbial communities.
5. Deforestation: Increasing erosion and disrupting nutrient cycles.

Impacts of Commercial vs. Subsistence Farming on Soil

Commercial farming:

• Often involves large-scale monocultures
• Heavy machinery use can cause soil compaction
• High chemical inputs may lead to soil pollution

Subsistence farming:

• Typically smaller scale with diverse crops
• Often uses traditional methods that maintain soil health
• May lead to soil degradation if practiced unsustainably due to poverty

Example

In the Amazon, large-scale soy farms have led to significant soil degradation, while some indigenous communities practice sustainable agroforestry systems that maintain soil fertility.

Causes and Effects of Soil Degradation

1. Erosion:
   • Causes: Wind, water, poor land management
   • Effects: Loss of topsoil, reduced fertility, sedimentation in water bodies
2. Toxification:
   • Causes: Pesticide overuse, industrial pollution
   • Effects: Harm to soil organisms, reduced biodiversity, potential food chain contamination
3. Salinization:
   • Causes: Poor irrigation practices, sea-level rise
   • Effects: Reduced plant growth, altered soil structure
4. Desertification:
   • Causes: Climate change, overgrazing, deforestation
   • Effects: Loss of productive land, biodiversity decline, social and economic impacts

Soil Conservation Measures and Management Strategies

1. Contour plowing: Reducing erosion on slopes.
2. Cover crops: Protecting soil between main crop cycles.
3. Terracing: Creating level platforms on hillsides.
4. Agroforestry: Combining trees with crops or livestock.
5. Conservation tillage: Minimizing soil disturbance during planting.
6. Crop rotation: Maintaining soil nutrients and breaking pest cycles.
7. Buffer strips: Planting vegetation along waterways to reduce runoff and erosion.

Tip

Combining multiple conservation strategies often yields the best results for soil health and productivity.

Note

Effective soil conservation requires understanding local ecological, economic, and social factors.

In conclusion, soil systems and terrestrial food production are intricately linked, with soil health being fundamental to sustainable agriculture. Understanding these connections is crucial for addressing global food security challenges while preserving environmental integrity.