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Geography 1100 Review.docx

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Geography 1100
D.Kim Holland

Food and Land I Organism: individual living thing: reacts, grows, reproduces, maintains homeostasis Eg. plant, animal, virus?, bacterium, fungus Ecosystem: interrelationships between environment and living organisms; energy flow Species: Agroup of plants or animals that have a high degree of similarity and can only interbreed among themselves to produce viable offspring (aquatic/terrestrial) WhatAre the Issues? Environmental Effects of Food/Fibre Production 30-40% of global cropland has been environmentally degraded Soils Erosion Loss of fertility Salinization Desertification Waterlogging Biodiversity Loss Loss and degradation of habitats from clearing grasslands and forests and draining wetlands Fish kills from pesticide run-off Killing wild predators to protect livestock Replacing thousands of crop strains with a few monocultures Air Pollution Greenhouse gas production from fossil fuel use Other pollutants from fossil fuels Pollution from pesticide sprays Water Water waste Aquifer depletion Increased run-off and flooding from land cleared to grow crops Sediment pollution from erosion Fish kills from contaminated run off Surface and groundwater pollution from fertilizers and pesticides Over fertilization of lakes from run off containing nitrates and phosphorus from livestock waste, fertilizers and food-processing wastes Humans Nitrates in drinking water Pesticides in food, water, air Etc. What is Soil? Mixture of eroded rock, organic matter, nutrients, water, air, living organisms (mostly detritivores) Potentially renewable resource Filters and holds water Slowly renewed Varying levels of maturity Soil Horizons Horizons Distinct texture and composition; differs with soil type Mature soils have at least 3 of the horizons O horizon Organic layer, also called surface litter: contains decomposing organic matter Ahorizon (topsoil) Contains humus (decomposed organic matter) as well as living soil organisms and plant root systems. Horizon most rich in nutrients B horizon (subsoil) Denser thanAhorizon, higher mineral content, lower fertility C horizon Contains rock in the process of being broken down (weathering) to produce new soil R horizon (bed rock) Solid rock The Science Behind What we Eat Essentially No Waste System!!! Producers – autotrophs; a.k.a. first trophic level Consumers – (1°, 2°, 3°); a.k.a. 2nd, 3rd, 4th trophic levels Detritivores - decomposers/detritus feeders (recyclers) Food Chains/ Food Webs Sequence of who eats or decomposes whom in a system Determines how energy moves through system Pyramid of Energy Flow Primary productivity is the currency of life Ameasure of chemical energy Chemical energy is transferred through the pyramid Productivity of Producers Gross primary productivity (GPP) - rate at which producers convert solar energy into chemical energy as biomass Net primary productivity (NPP) – rate at which new energy is made by producers and available for use by consumers Net Primary Productivity Tells us about what can be supported in that ecosystem Major limiting factor for life 59% of Earth’s NPP is produced on land; 41% in aquatic systems Why should we care about NPP? Our lives depend on NPP Directly or indirectly destruction of NPP impacts us Major Types of Agriculture 1. Industrialized (high-input) High amounts of fossil fuels, water, fertilizers, pesticides Plantation – tropical developed countries 2. Traditional Subsistence agriculture Human labour, some animals; survival Intensive agriculture Increased inputs; survival and income Techniques Used in TraditionalAgriculture Interplanting – several strategies Polyvarietal cultivation Polyculture Intercropping; companion Agroforesty (a.k.a.alley cropping) Food and Land II 1. Food Production Global and Canada 25% of agriculture feeds 80% of people 2. Environmental Issues Affecting Soil Soil degradation by erosion, desertification, salinization and water logging 3. Solutions to Environmental IssuesAffecting Soil Systems that provide food: Croplands (77%) Rangelands (16%) Ocean fisheries (7%) Technological advances have contributed to dramatic increases in all three systems Will it be enough? / Will degradation limit NPP? (possible midterm question) What are we Eating? 30, 000 edible plant species 14 plant species/8 terrestrial animals supply 90% of global caloric intake Primary plants Wheat, rice, corn: (>50% calories) (applies to 2/3 of population) Primary animals/protein Fish, beef, pork and chicken The Great Irony > 1 billion people do not have enough food to maintain good health > 1 billion people confront health issues assoc. with an excess of food Food Production: Canada’s Role 8.5% of GNP, 10% of employment Fewer farms and larger farms $21B export and surplus Most land unsuitable Prairie province 83%, ON/QC 13% Environmental costs Soil erosion, water pollution, pesticide use, habitat disruption Ways to Increase Food Production Green Revolution techniques More useable land; higher yields/unit area 3 Steps 1. Monocultures; genetically engineered high-yield varieties (selection) 2. Large inputs of water, fertilizers and pesticides 3.
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