Rioting in response to soaring food prices recently has broken out in Egypt, Cameroon, Ivory Coast, Senegal and Ethiopia. In Pakistan and Thailand, army troops have been deployed to deter food theft from fields and warehouses.
Intensive tillage, soil erosion, and insufficient added residues Soil Degradation Aggregates break down Soil organic matter decreases Increased erosion by wind and water Surface becomes compacted, crust forms Less soil water storage, less diversity of soil organism, fewer nutrients for plants More soil organic matter is lost Crop yields are reduced Hunger and malnutrition result
… it is our work with living soil that provides sustainable alternatives to the triple crises of climate, energy, and food. No matter how many songs on your iPod, cars in your garage, or books on your shelf, it is plants’ ability to capture solar energy that is at the root of it all. Without fertile soil, what is life? —VANDANA SHIVA, 2008
Building Healthy Soils Fred Magdoff firstname.lastname@example.org
Aggregates after stability test % of aggregates stable to 1.25cm rain/5mins: 2mm sieves Conventional management ~20% - low Organic management ~70% - high
Add organic matter Increased biological activity (& diversity) Reduced soil-borne diseases, parasitic nematodes Aggregation increased Decomposition Humus and other growth promoting substances Pore structure improved Nutrients released Harmful substances detoxified Improved tilth and water storage HEALTHY PLANTS
carbon dioxide (CO2) (0.04% in the atmosphere) root respiration and soil organic matter decomposition photosynthesis respiration in stems and leaves crop harvest crop and animal residues carbon in soil organic matter erosion
Overall strategies of ecologically-based agriculture a) create soil & above ground conditions for healthy plants with enhanced defenses b) stress pests c) enhance beneficials
Prevention (of symptoms and consequences of weak ecosystem) Build internal strengths into agricultural ecosystem Routine ecologically sound practices during season to keep plants healthy Reactive management
Preventive management pre-season through planting time (building internal strengths into the system) • create soil & above ground conditions for healthy plants with enhanced defenses • stress pests • enhance beneficials 1. Crop/plant selection & planting management; habitat conservation & enhancement of field and surroundings 2. Build healthy soil (below ground habitat conservation & enhancement)
Building Healthy Soil 1. Add plentiful amounts of organic materials from crop residues (including cover crops) well as off-field organic materials such as animal manures and composts.
Building Healthy Soils 2. Keep the soil covered with living vegetation and/or crop residue.
Use cover crops or perennial sod cover routinely. • Reduce tillage intensity. • Supplies food and habitat for maintaining biodiversity (helps beneficials at expense of pests) • Suppresses weeds, insect, and disease cycles • Helps grow healthier plants because: • a) development of better soil tilth b) supplies nutrients and soil holds water better c) lessens compaction d) etc.
Building Healthy Soils 3. Use better crop rotations.
Building Healthy Soils 4. Reduce tillage intensity.
Many different reduced till systems — conservation till, ridge till, zone-till, no-till. • Better planters help. • Cover crops can help.
Building Healthy Soils 5. Use other practices that reduce runoff and erosion.
Building Healthy Soils 6. Reduce severity of compaction.
Don’t travel on wet soils. • A lasting injury is done by ploughing • land too wet. • S.L. Dana, 1842
Use controlled traffic lanes (“permanent” beds). • Better load distribution. • Increase organic matter. • Etc.
Building Healthy Soils 7. Use best management techniques to supply nutrients to plants without degrading the environment.
Farm boundary farm-grown crops crops crop residues fertilizers, lime, organic amendments leaching, runoff, and volatilization soil Nutrient Cycles vs. Nutrient Flows
Use Multiple Tactics Better nutrient timing, placement, and amounts Reduce tillage Reduce compaction Cover crops Healthier Crops Better rotations Control erosion Add various sources of organic materials (crop residues, manures, composts, etc.)