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Ag Production and the Environment
Text extracted from The World Food Problem Leathers & Foster, 2004
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Global Soil Regions
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Erosion Soil removed by Agricultural cause: Wind water Plowing
bare fields Absence of roots
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Chemical Degradation of Soil
Nutrient depletion Especially if same crop grown every year Salinization Irrigation with low levels of salt Salt build up when dries Acidification Too much fertilizer Drainage problems Pollutants Oil Pesticides Salinization
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Physical degradation of soil
Less porous Compaction by Heavy machines Animals Waterlogging Roots die Due to Over irrigation Poor drainage Soil compaction
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Extent of Land Degradation
38% total cropland degraded worldwide 2 billion hectares 83% by erosion 12% chemical 5% physical 5-10 million new hectares degraded each year New land must be put into production to compensate Generally poor quality Overgrazed degraded soil
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Irrigation Problems Water Quality degradation Land degradation:
Salt-water intrusion in coastal areas due to lower water table Leeches salt into groundwater: unusable Runoff carries fertilizer, pesticide residues Land degradation: SoilErosion Waterlogging Salinization acidification
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Ag Chemicals Can lead to Chemical manufacture can be dangerous
Land degradation Water pollution Health problems Chemical manufacture can be dangerous Explosion at fertilizer plant in Bhopal India in 1984 Killed thousands Union Carbide Chemical Plant, Bhopal India
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David Pimentel Believes carrying capacity has already been exceeded
Earth can support 2 billion at high standard of living Current yields not sustainable
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Julian Simon Optimistic about future ag production
Technology will solve problems Drip Irrigation Fish Farming GMOs for Pest resistance Drought resistance Salt resistance
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Global Warming Agriculture contributes to global warming
CO2 released from plant decomposition Co2 = 80% greenhouse gases Methane released from Rice paddys Cattle Belching Nitrous Oxide released from Fertilizer use
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Global Warming Impact on Agriculture: Flooding of coastal land
Affect crop yields Increase CO2 Boosts crop growth Increase water-use efficiency Increase extreme weather Increase insects, disease Shift climate zones North Africa better North America worse
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Bioenergy
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Bioenergy
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