Sustainable Agriculture and Agroecology Notes

Sustainable Agriculture and Agroecology

• Sustainable agriculture aims to protect the environment, expand natural resources, and improve soil fertility.
• It seeks to increase farm income, promote environmental stewardship, enhance the quality of life for farm families, and increase food production.

Definition of Sustainable Agriculture

• An integrated system of plant and animal production practices that:
  • Satisfies human needs.
  • Enhances environmental quality.
  • Efficiently uses resources.
  • Sustains economic viability.
  • Enhances the quality of life for farmers and society.

Goals of Sustainable Agriculture

• Environmental health.
• Economic profitability.
• Social and economic equity.
• Meeting current needs without compromising future generations.
• Integrating economic, ecological, and social systems.

Themes in Sustainability

• Stewardship of resources.
• A systems approach.
• Long-term perspective.
• Continual change and modification.
• Shared responsibility.

Sustainable Agricultural Management Practices

• Reduce reliance on pesticides and nonrenewable energy.
• Increase reliance on internal cycling and local inputs.
• Conserve habitat and enhance biodiversity.
• Preserve air quality.
• Select resistant species and varieties.
• Diversify crops and cultural practices.
• Manage soil as a living resource.
• Conserve soil and protect it from erosion.
• Manage water to improve conservation and protect groundwater.

Types of Sustainable Farming

• Organic farming.
• Biodynamic.
• Permaculture.
• Agroecological systems.
• Low-input.

Why Sustainable Agriculture?

• Avoid environmental damage.
• Counter economic concentration of agribusiness.
• Prevent loss of farms.

Environmental Sustainability

• Management of a production system with interactions between soil, water, plants, animals, climate, and people.
• Mimicking natural processes and ecosystem function.
• Diversifying farms to manage risks.

Farm as an Ecosystem

• Energy flow: Capturing sunlight through photosynthesis and cycling energy through the food chain.
• Water cycle: Enhancing water entry, storage, and reducing runoff.
• Mineral cycle: Recycling nutrients from soil to crops and animals and back to the soil.
• Biodiversity: Greater diversity equals greater stability.

Soil Fertility Management

• Maintain soil cover.
• Maintain or build soil organic matter.
• Properly timed or limited tillage.
• Irrigation management.
• Sound crop rotations.
• Balanced nutrient levels and pH.

Soil Fertility: Cover Crops

• Build soil and improve physical properties by cycling carbon and nitrogen.
• Suppress nematodes and soil-borne diseases.
• Suppress weeds.
• Reduce erosion.

Soil Fertility: Composts

• Build soil organic matter and add nutrients.

Animal Manure

• Integrate grazing animals to produce compost.
• Use fresh or undecomposed manure.

Soil Fertility: Tillage

• Prepares the ground for seedlings, provides residue incorporation, and improves soil aeration and water infiltration.

Reduced and No-Tillage Systems

• Residue cover protects soil from erosion and retains moisture.
• Builds soil organic matter.

Soil Amendments & Supplemental Fertilizers

• Balance nutrient inputs with outputs to avoid depletion or accumulation. If $inputs > outputs$ then risk of excess nutrients. If $inputs < outputs$ then there's a potential risk of plant nutrient deficiencies.

Soil Fertility: Crop Rotation

• Breaks weed and pest cycles and provides complementary fertilization.
• Ideal rotation includes crops, cover crops, sod, and livestock.

Crop Rotation Considerations

• Avoid rotating crops with similar pests and diseases.
• Maximize nutrient use.

Guidelines for Crop Rotations

• Follow legume-sod crops with high-nitrogen-demanding crops.
• Use longer periods of perennial crops on erosive soils.

Ecological Weed Management

• Improve soil conditions to optimize crop growth and minimize weed pressure.
• Clean equipment to avoid transporting weed seeds.
• Prevent weeds from forming seed heads.
• Compost animal manure to destroy weed seeds.
• Work with neighbors to manage weeds.

Cultural Weed Practices

• Crop rotations, tillage, planting and cultivation, rotational grazing, mowing, irrigation, flame weeding and mulches.

Ecological Pest Management

• Intercropping, diversity, and cover cropping.
• Crop rotation and farmscaping.
• Use of resistant varieties.

Integrated Pest Management (IPM)

• Uses habitat modification and cultural, physical, biological, and chemical practices to minimize crop losses.

Plant Disease Manipulations

• Environment manipulations: spacing and irrigation.
• Host manipulations: resistant cultivars and crop rotation.
• Pathogen manipulations: removal of host tissue or organic chemical controls.

Plant Disease Management

• Use crop rotations, biodiversity, resistant cultivars, and soil fertility measures.
• Compost teas and foliar sprays can help control fungal diseases.