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Land and Water Use
FEEDING A GROWING POPULATION
Human Nutritional Requirements
Human Nutritional Requirements
• Calories– Male– Female
• Nutrition– Protein:– Carbohydrate:– Fat:
Human Nutritional Requirements
• Food source– 100 species of plants (350,000 available)• Wheat and rice supply over half human Calories
– 8 animal species supply 90% of world’s needs
Types of Agriculture
Types of Agriculture
• Soil Prep1) High input:
2) Subsistence:
3) Tillage:
4) Low Till, no till:
Types of Agriculture
• Crop type1) Crop Rotation:
2) Monoculture:
3) Polyculture:
Green Revolution
• 1950-1970
• 1970
Genetically Engineered Crops
• 75% of all crops are genetically engineered– Pest, drought, mold, salinity resistance– Higher protein yield– Higher vitamin content
Genetically Engineered Crops
Prosa) b) c) d) e) f)
Consa) b) c) d) e) f)
SUSTAINABLE AGRICULTURE
Main Goals
1. 2. 3. 4.
Efficient Use of Inputs
1. 2. 3.
Selection of Site, Species, and Variety
• Pest-resistant crops• Location (climate, topography)• Soil type and depth• Previous crop history• “Do your homework”
Species Diversity
• Reduces economic risk• Can improve soil• Optimum diversity – livestock and crops
Soil Management
• Reduces need for:
• Reduces issues:
Soil Management
• Managing Soil– Cover crops– Compost/manure– Reduce tillage– Maintain soil cover – plants/mulch– Regular additions of organic matter
Relevant Laws
• Conservation Reserve Program (CRP) 1985– Farmers paid for land placed in reserve
• Food Security Act 1985– Farmers must develop and implement soil
conservation programs to remain eligible for subsidies, etc.
• 2002 Farm Security and Rural Investment Act– Subsidies: price supports and farm income
CONTROLLING PESTS
Types of Pesticides
• How pesticides differ1. 2. 3.
Types of Pesticides
• Biological– Living organisms– Ladybugs
• Carbamates (urethanes)– Affect nervous system– Very water soluble– Potent (100g = 2000g DDT)
Types of Pesticides
• Chlorinated hydrocarbons (DDT)– Affect nervous system– Persistent• Can remain in ecosystem
for up to 15 years
• Fumigants– Sterilize soil– Prevent pest infestation of stored grain
Types of Pesticides
• Inorganic – mercury, lead, copper– Highly toxic– Accumulate
• Organics (natural)– Derived from plants
(chrysanthemum)
Types of Pesticides
• Organophosphates - Dursban– Extremely toxic – affects nervous system– Not persistent in environment
Costs and Benefits
• Many pests have increased in numbers– – – –
Pros of Pesticides
• Kill unwanted pests that cause disease• Increased food supplies• More food means less expensive• Newer pesticides are safer and more specific• Reduced labor cost• Agriculture is more profitable
Cons of Pesticides
• Accumulate in food chains• Pests develop resistance• $5-10 in damage done environmentally for every
$1 spent• Expensive• Biomagnification in aquatic environments (runoff)• Ineffective – only 5% reaches a pest• Threatens endangered species, pollinators,
human health
Integrated Pest Management (IPM)
• Pest control strategy that uses many methods• Reduce or eliminate traditional pesticides• Goal is to control numbers, not eradicate
Relevant Laws
• Federal Insecticide, Fungicide, & Rodenticide Control Act (FIFRA) 1947– Regulates manufacture and use of pesticides
• Federal Environmental Pesticides Control Act 1972– Requires registration of all pesticides in US
commerce
Relevant Laws
• Food Quality Protection Act 1996– Emphasizes protection of infants and children in
reference to pesticide residue in food
Irrigation
Irrigation
• ¾ of all freshwater• Use depends on climate and industrialization• Up to 70% of irrigation water is lost– – –
Drip irrigation
• Reduces water loss through evaporation• Expensive to install• Used on 1% of crops
worldwide
Sustainable Irrigation Limits
• Increased costs• Depletion of current sources• Competition from urban areas• Restoration of wetlands and fisheries• Salinization
