5.2 Agriculture & Food

Land is

a finite resource, and the human population continues to increase and require feeding

Food security

the physical and economic availability of food, allowing all individuals to get the balanced diet they need for an active and healthy life

Food insecurity can be measured at different levels of severity:

• Moderate Food Insecurity → uncertain about their ability to obtain food and have had to reduce the quality and/or quantity of the food

• Severe Food Insecurity → have typically run out of food and have gone a day or more without eating

Marginalized groups are more vulnerable if their needs are not taken into account in land-use decisions

consider indigenous peoples and other groups that may be marginalized or have a low socioeconomic status, such as members of a low caste or women farmers or people in low-income countries

World agriculture produces

enough food to feed eight billion people, but the food is not equitably distributed and much is wasted or lost in distribution

Agricultural systems can be classified in a number of ways:

• Outputs from the farm system—arable, pastoral/livestock, mixed, monoculture or diverse.

• Reasons for farming—commercial or subsistence, sedentary or nomadic.

• Types of inputs required for the farm system—intensive or extensive, irrigated or rain-fed, soil-based or hydroponic, organic or inorganic.

Agriculture and soil variation

agriculture systems across the world vary considerably due to the different nature of the soils and climates.

Soils in different biomes have very different potentials for crop types and productivity.

Current Global Strategies to Achieve Sustainable Food Supply

include reducing demand and food waste, reducing greenhouse gas emissions from food production and increasing productivity without increasing the area of land used for agriculture

Reducing demand and food waste

Decreasing consumption through dietary shifts and reducing losses in production, storage, and distribution.

• Example: Plant-based meat substitutes Extend shelf life of food

• Pros: Reduces resource use, lowers greenhouse gas emissions, and improves food security

• Cons: Requires behavioural changes and effective waste management systems.

Reducing greenhouse gas emissions from food production

Minimizing agricultural contributions to climate change

• Examples: Managing the timing and method of nitrogen application to crops to reduce nitrogen loss to the atmosphere; low methane rice  reduce methane release by ruminants  in-field solar powered fertilizer production process

• Pros: Mitigates climate change impacts, improves air quality.

• Cons: Requires technological advancements and changes in farming practices.

Increasing productivity without increasing land use

Producing more food on existing farmland.

• Example: Genetic modification to boost yields

• Pros: Preserves natural habitats, and reduces deforestation

• Cons: Potential for increased use of inputs (fertilizers, pesticides), leading to environmental concerns.

Plant-based Meat Substitutes

Foods made from plants (e.g., soy, peas, mushrooms) designed to replicate the taste, texture, and nutritional profile of animal meat, reducing the need for livestock farming.

Low Methane Rice

Rice varieties or farming methods designed to reduce methane emissions from flooded rice paddies, contributing to lower greenhouse gas outputs

Extended Shelf Life for Food

Technologies (e.g., packaging innovations, preservatives, genetic traits) that slow down spoilage and extend how long food stays fresh after harvest or production.

In-field Solar-powered Fertilizer Production

Systems that use solar energy to produce fertilizers directly on farms, reducing dependency on centralized industrial fertilizer production and fossil fuels.

Reducing Nitrogen Loss to the Atmosphere

Techniques (e.g., precision agriculture, slow-release fertilizers) aimed at minimizing nitrogen emissions from fertilizers, ensuring more nitrogen stays in the soil to benefit crops.

Reducing Methane Release by Ruminants

Feeding strategies, supplements, or breeding methods that lower methane produced by cows, sheep, and goats during digestion.

Genetic Modification to Boost Yields

Biotechnological methods to alter plant or animal DNA to improve productivity, such as pest resistance, drought tolerance, or faster growth

Agriculture systems across the world vary considerably due to the different nature of the soils and climates,

soils in different biomes have very different potentials for crop types and productivity

Tropical Rainforest

Oxisols (highly weathered, acidic, nutrient-poor)

Short-term fertility with shifting cultivation

Rapid nutrient leaching, poor for sustained farming

Savanna (Tropical Grasslands)

Alfisols & Ultisols (moderate fertility)

Good for grazing, some crops (e.g., sorghum, millet)

Seasonal drought, poor water retention

Temperate Grasslands

Mollisols (deep, fertile)

Excellent for cereal crops (wheat, corn)

Prone to erosion if mismanaged

Temperate Forests

Alfisols (fertile, loamy)

Good for mixed farming, fruit, and vegetables

Acidification in wet areas

Deserts

Aridisols (dry, low organic matter)

Limited, but possible with irrigation (dates, cotton)

Water scarcity, salinity buildup

Tundra

Gelisols (permafrost soils)

Minimal agriculture (some cold-resistant crops in summer)

Permafrost limits root growth, cold temperatures

Mediterranean

Alfisols, Entisols

Specialized crops (olives, grapes, citrus)

Summer drought stress

Agricultural systems are varied, with different factors influencing the farmers’ choices.

These differences and factors have implications for economic, social and environmental sustainability

Outputs

• Arable: Crops like wheat, corn, soybeans

• Pastoral/Livestock: Meat, milk, wool from animals

• Mixed: Combination of crops and livestock

• Monoculture: Single crop grown repeated

• Diverse: Multiple crops grown together

Reasons for farming

• Commercial: Generates income for farmers

• Subsistence: Produces food for the farmer's family

• Sedentary: Fixed location for farming

• Nomadic: Moves from place to place to find resources

Inputs

• Intensive: High use of external inputs (fertilisers, machinery)

• Extensive: Low use of external inputs, relies on natural resources

• Irrigated: Receives supplemental water through irrigation

• Rain-fed: Relies solely on rainfall for water

• Soil-based: Plants grown in soil

• Hydroponic: Plants grown in water with dissolved nutrients

• Organic: Uses organic fertilisers and pest control methods

• Inorganic: Uses synthetic fertilisers and pesticides

Nomadic pastoralism and slash-and-burn agriculture

are traditional techniques that have sustained low-density populations in some regions of the world, as indigenous cultures modernize and exist in higher population densities or in fixed locations, these practices become less sustainable

The Green Revolution (also known as the Third Agricultural Revolution in the 1950s and 1960s)

• used breeding of high-yielding crop plants (wheat, rice) combined with increased and improved irrigation systems, synthetic fertilizer and application of pesticides to increase food security.

• has been criticized for its sociocultural, economic and environmental consequences

Pros of Green Revolution

• Higher Food Production

• Reduced Hunger & Poverty

• Better Nutrition

• Multiple Harvests per Year

• Modern Farming Technologies

Cons of Green Revolution

• Soil degradation, water pollution

• Fossil Fuel Dependence

• Loss of Crop Diversity

• Widened Inequality

• Urban Migration of Farmers

• Unsustainable Long-Term

Synthetic fertilisers

are needed in many intensive systems to maintain high commercial productivity at the expense of sustainability, in sustainable agriculture, there are other methods for improving soil fertility

Fallowing

allows soil to rest and replenish nutrients naturally

Organic fertilisers (farm animals or humanure)

enrich the soil with essential nutrients from plant and animal matter

Herbal mixed leys

introduce diverse plant species to improve soil structure and fertility

Mycorrhizae (symbiotic association between a fungus and a plant)

are beneficial fungi that enhance nutrient uptake and water retention

Continuous cover forestry

protects soil from erosion while providing organic matter

Agroforestry

integrates trees with crops to improve soil health and biodiversity

Soil conservation from erosion—water and wind

• Water →terracing, contour ploughing, bunding, drainage systems, use of cover crop

• Wind → planting tree/hedge windbreaks, use of cover crops

Conservation of fertility with soil conditioners

lime, use of organic materials, such as compost, green manure

Cultivation Techniques

avoid marginal land, avoid overgrazing or overcropping, strip cultivation, mixed cropping, crop rotation, reduced tillage, agroforestry, reduced use of heavy machinery

Many of the techniques help conserve soil from a number of problems


• Terracing - reduces soil erosion, controls water run off by holding water at each level

• Contour Ploughing - each row acts as a small dam to help slow down water runoff and soil erosion

• Strip Cultivation growing crops in long strips and alternate between types of crops to prevent runoff and soil erosion

• Cover Crops - fast growing crops that cover soil between rows on main crop to prevent soil erosion and add nutrients back to the soil

• Alley Cropping - plants planted in alleys between trees and shrubs to provide shade and soil moisture retention

• Avoiding the use of marginal lands - if it shouldn’t be farmed -stop farming

Conventional Tillage

• soil is physically broken up by ploughing

• open and loose soil structure

• well aerate and moist

• reduce weeds

• surface of the land is cleared

Conservation Tillage

• crop residue is left

• act as a mulch

• increases organic material

• more water infiltration

• reduces run-off

• reduces  water erosion

• low emissions (no machines)

• problem with weed

Humans are omnivorous, and diets include fungi, plants, meat and fish. Diets lower in trophic levels are more sustainable

Terrestrial food comes mostly from lower trophic levels (plants, herbivores).

Aquatic food often comes from higher trophic levels, where energy storage is smaller.

• Only ~10% of energy is passed to the next level (2nd law of thermodynamics), making it more efficient to eat lower down the food chain

• Cattle & sheep are inefficient: high feed, water, and CO2 emissions per kg of meat

• Chickens & pigs are more efficient but still resource-intensive.

Rising Meat Demands

• Economic growth (e.g., China, India, Brazil) increases meat consumption.

• Meat provides iron but increases fat intake and resource use.

• Land and water use for meat is far higher than for plants.

• Low feed-to-meat energy conversion diverts cereal crops to livestock.

Consumer Choice & Sustainability

• MEDCs import exotic, non-seasonal foods, raising global resource use.

• LEDCs may prioritize cash crops for export over local food needs.

• Solutions include local production initiatives & better food labelling to support informed choices.

What factors influence society's choice of food production?

1. Climate

2. Culture & Religion

3. Political

4. Socio-economic