Subsistence Agriculture → The production of food to feed oneself and one’s family.
Industrialized Agriculture → Large scale production of crops and livestock for sale. Emphasizes high yields. Relies on the large input of energy to run machinery, irrigate crops and produce fertilizers and pesticides.
Sustainable Agriculture → The growing of crops and livestock in an environmentally friendly way.

Features of Subsistence / Low Input Agriculture

Human Labor
Slash and Burn
Shifting Cultivation
Fallow Periods
Animal Manure
Mixed Cropping

Negative Effects of Subsistence / Low Input Agriculture

Food insecurity
Slash and Burn Cultivation leads to:
- Deforestation and vegetation loss
- Shifting Cultivation as plots are abandoned after 2-5 years due to loss of soil fertility.
- Increased fire hazards and global warming.

Green Revolution → Transformation in agricultural practices between 1940’s and 1960’s. The objective was to eradicate famine and increase food production. Shift from subsistence to industrialized agriculture.

Features of Industrialized / High Input Agriculture

Mechanization (fossil fuel use)
Conventional Tillage
Monocropping
Genetic Engineering
Synthetic Pesticides
Synthetic Fertilizers
Irrigation

Mechanization and its Negative Effects

Causes land degradation through soil compaction by heavy machinery
Increases soil erosion
Causes decline in soil fertility
Erosion damage causes decreased water quality

Conventional Tillage and Its Negative Effects

In conventional tillage the soil is extensively broken up. This:

Disrupts the soil structure
Increases soil erosion
Causes decline in soil fertility
Erosion damage causes decreased water quality

Monocropping and Its Negative Effects

Also called monoculture
Cultivation of a single crop, usually on a large area of land
Simplifies ecosystems reducing biodiversity
Encourages the build up of pests thus increasing the use of pesticides
Depletes the soil of nutrients

Pesticides

Definition → Any chemical designed to kill or inhibit the growth of an organism that people consider undesirable.

Types of Pesticides

Synthetic or inorganic pesticides are man-made
Organic pesticides are based on natural plant compounds such as neem.

Benefits of pesticides

Reduced pest and disease levels results in
- Increased production
- Improved food quality

Negative Effects of Synthetic Pesticides

Genetic Resistance → Fast-breeding insect species undergo natural selection and develop genetic resistance to chemical pesticides.
Mobile → When applied pesticides may move through the soil, water or air.
Health Impacts → Pesticides have been linked to cancers and low sperm count
Loss of Biodiversity
- Reduction in nutrient recycling soil organisms
- Loss of plant genetic diversity
- Endangerment & extinction of wildlife
Persistent → pesticides adhere to sediment and become bioaccumulated and biomagnified

Negative Effects of Synthetic Pesticides Use

Bioaccumulation → Increase in concentration of contaminants in the tissue of organisms
Biomagnification → Increase in concentration of contaminants up the food chain

Fertilizers

Definition → Substances that add plant nutrients to soil and improves its ability to grow crops.

Types of Fertilizers

Commercial Inorganic Fertilizer → Commercially prepared mixtures of plant nutrients
Organic Fertilizer

N. B. Conventional agriculture relies on synthetic inorganic fertilizers

Negative Effects of Synthetic Fertilizer Use

Supply only 2 or 3 of the 20+ nutrients needed by plants
Leads to soil compaction
Water pollution
- Increases nitrates and phosphates in waterbodies, drinking water, food and air
- Leads to eutrophication in the aquatic environment.

Genetic Engineering

Definition → Transfer of genetic material from one organism to another.

Benefits:

Improve the appearance and taste of agricultural produce.
Increase shelf life of fruits and vegetables.
Provides genetic resistance to pest and diseases which reduces the need for application of pesticide to crops or livestock.

Negative Effects

Genetically altered organisms might mutate and cause unforeseen effects
Natural population balances in an ecosystem may be disturbed
Health impacts such as allergic reactions to introduced genes in foods

Lack of GMO labeling prevents consumers from making a choice not to use GMO’s.

Irrigation

Definition → The application of water to crops.

Types of Irrigation

Natural/Rainfall
Flood irrigation
Overhead/sprinkler
Drip irrigation - most efficient water use (90%)

Flood Irrigation

Flood irrigation is wasteful of water and causes land degradation because of:

Soil erosion
Salinization (build up of salts in the soil)
Waterlogging.

Land Degradation

Definition → Deterioration in the quality of land, its topsoil, vegetation, and or water resources. Usually associated with industrial agriculture and may lead to desertification.

Caused by:

Overgrazing (animals feed too long or their numbers exceed the carrying capacity of rangeland)
Flood irrigation
Deforestation
Conventional ploughing.

Desertification → Process whereby productive crop or range land turns into unproductive desert.

Associated with industrial agriculture as well as rural poverty.
The livelihoods of nearly one billion people in some 100 countries are threatened by desertification.
About 25 per cent of the Earth's land, or 3.6 billion hectares, is desertified.

Sustainable Agriculture

Crops grown in harmony with the environment
Health of humans and livestock important
Environment important
Social justice important

Examples: Organic agriculture and Permaculture

Features of Sustainable Agriculture

Companion cropping/mixed farming
Soil conservation (preventing soil erosion)
Alternatives to synthetic fertilizers (addition of organic matter)
Use of alternatives to the use of synthetic pesticides

Mixed Cropping and Its Benefits

Includes companion cropping and intercropping.
Cultivation of more than one crop.
Reduces the build up of pests thus reducing the use of pesticides
Including legumes in the system adds nitrogen to the soil.

Soil Conservation Methods

Methods used to:
- reduce soil erosion
- prevent depletion of soil nutrients
- restore nutrients
Most methods involve keeping the soil covered with vegetation

Major Methods Include:

Conservation tillage
Contour farming
Terracing
Alley cropping
Windbreaks/ Shelterbelts
Maintaining & restoring soil fertility

Conservation Tillage → Crop cultivation with little or no soil disturbance

Minimum Tillage
No-till Farming

Contour Farming → Rows planted along the contour of the land. Used mainly on gently sloping land.

Terracing → Level areas created across the contour. Used on steeper slopes.

Alley Cropping → Planting crops with rows of trees on each side or amongst trees of the forest.

Windbreaks/Shelterbelts → Row of trees planted to block wind flow.

Organic Fertilizer

Organic materials, such as animal manure, applied as a source of plant nutrients. They improve soil structure, helps to retain soil moisture and stimulate beneficial bacteria and fungi.

Three Basic Types of Organic Fertilizer

Animal Manure
Green Manure
Compost

Animal Manure → Dung and urine of farm animals.

Green Manure → Freshly-cut or still-growing vegetation that is ploughed into the soil.

Compost → Partially decomposed organic plant and animal matter

Made up of animal manure, topsoil, kitchen scraps
Rich, natural fertilizer

Alternatives to Pesticides

Agricultural Methods:

Tillage of land → to expose pests
Proper timing of planting, fertilizing and irrigating
Crop rotation
Plant rows of hedges or trees (habitat for natural predators to pest)

Genetic Control

Breed crops and animals resistant to pests
Sterilize members of the pest population

Natural Enemies (Biological Control) → Predators, parasites & pathogens can be encouraged or imported to regulate pest populations.

Consideration → care should be taken to avoid biotic pollution.

Pheromones → Chemical sex attractant that may be used in traps.

Hormones → Chemical sex attractant that may be used in traps.

Quarantine → Restriction of the importation of exotic plant and animal material that might harbor pests.

Integrated Pest Management (IPM)

Combines use of biological, cultural and chemical control
Non-chemical controls used as far as possible; pesticides used sparingly when other methods fail

Sustainable Livestock Production

Free Range → Livestock allowed to forage outdoors
Integrating crop and livestock production to create closed system
Natural remedies replace antibiotics
Hormones avoided

Legislations

Town and Country Planning Act 1958 → Primary law governing land use in Jamaica
The Watersheds Protection Act, 1963 → Law governing watersheds in Jamaica
The Forest Act 1996 → Law for the management and reservation of forests
Country Fires Act 1955 → Aims to prevent the lighting of arbitrary fires in rural area
The Pesticides Act 1987 → Regulates the manufacture, importation use and sale of pesticides.

Note