Land and Water Use
FEEDING A GROWING POPULATION
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
Soil Prep 1)High input: 2)Subsistence: 3)Tillage: 4)Low Till, no till:
Types of Agriculture Crop type 1)Crop Rotation: 2)Monoculture: 3)Polyculture:
Green Revolution
Genetically Engineered Crops 75% of all crops are genetically engineered – Pest, drought, mold, salinity resistance – Higher protein yield – Higher vitamin content
Genetically Engineered Crops Pros a) b) c) d) e) f) Cons a) b) c) d) e) f)
SUSTAINABLE AGRICULTURE
Main Goals
Efficient Use of Inputs
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 Farm Security and Rural Investment Act – Subsidies: price supports and farm income
CONTROLLING PESTS
Types of Pesticides How pesticides differ
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
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