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The Great Hunger of 2008
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 organic matter decreases
Surface becomes compacted, crust forms Less soil water storage, less diversity of soil organism, fewer nutrients for plants
Aggregates break down
More soil organic matter is lost
Crop yields are reduced
Increased erosion by wind and water
Hunger and malnutrition result
Soil Degradation
… 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
% of aggregates
stable to 1.25cm
rain/5mins:
2mm sieves
Organic
management
~70% - high
Conventional
management
~20% - low
Aggregates after stability test
Add organic matter
Increased biological activity (& diversity)
Decomposition
Nutrientsreleased
Aggregationincreased
Pore structureimproved
Humus and othergrowth promotingsubstances
Reducedsoil-borne diseases,parasitic nematodes
Improved tilthand water storage
HEALTHY PLANTS
Harmful substances detoxified
crop harvest
carbon dioxide (CO2)(0.04% in the atmosphere)
erosion
photosynthesis
root
respiration
and soil
organic
matter
decomposition
carbon in
soil
organic matter
respiratio
n
in stems
and
leavescrop and
animal
residues
a) create soil & above ground conditions forhealthy plants with enhanced defenses
b) stress pests
c) enhance beneficials
Overall strategies of ecologically-based agriculture
Build internal strengths into agricultural
ecosystem
Prevention (of symptoms and consequences of weak
ecosystem)
Routine ecologically sound practices during season to keep plants
healthy
Reactive management
Preventive managementpre-season through planting time
(building internal strengths into the system)
create soil & above ground conditions forhealthy 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)
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 Soil
vs.
2. Keep the soil covered with living vegetation and/or crop residue.
Building Healthy Soils
• 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.
Use cover crops or perennial sod cover routinely.
Reduce tillage intensity.
3. Use better crop rotations.
Building Healthy Soils
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.
6. Reduce severity of compaction.
Building Healthy Soils
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.
fertilizers,
lime, organic
amendment
s
leaching,
runoff, and
volatilizatio
n
crops
farm-grown crops
soil
crop
residues
Farm boundary
Nutrient Cycles vs. Nutrient Flows
Healthier Crops
Better
rotations
Reduce
compaction
Add various sources of
organic materials (crop residues,
manures, composts, etc.)
Cover crops
Reduce
tillage
Control
erosion
Better nutrient
timing, placement,
and amounts
Use
Multiple Tactics
