ENVR2350

• World population will swell to 9 billion by the middle of the century
• Agricultural land covers 38% of earths land surface
• Agriculture: Practice of raising crops and livestock for human use and consumption
• Cropland: Land use to raise plants for human use
• Rangeland: land used for grazing livestock
• Agriculture first appeared 10,000 years ago and was invented independently by different cultures.
• Agriculture is a form of intensification – a way to increase the productivity and carrying capacity of given unit of land
• Traditional agriculture = biologically powered agriculture, using human and animal muscle power
• Subsistence agriculture = families produce only enough food for themselves
• Industrialized agriculture = a more recent form of agriculture using large-scale mechanization and fossil fuels to boost yields
• Monoculture = vast fields of single types of crops – occupies about 25% of the world’s croplands
• Food Security = the guarantee of an adequate reliable and available food supply to all people at all times. There is no guarantee that agriculture production will continue to outpace population growth as it depends on water resources and crop diversity and the ability of soils to support crops and livestock.
  • Undernourishment = people receive less than 90% of their daily caloric needs
  • Overnutrition = receiving too many calories each day
  • In Canada, 48% of adults exceed their healthy weight and 14% are obese
  • Malnutrition = a shortage of nutrients the body needs
    • The diet lacks adequate vitamins and minerals
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• Green revolution = increase in agricultural productivity during mid to late twentieth century including: increased food production, devoting more energy and greatly increasing use of irrigation, fertilizers and pesticides
  • Extensification = bringing more land into production
  • Intensification = better productivity per unit of land
  • Positive effects of on natural resources of Green revolution: reduced pressure to convert natural lands, prevented deforestation and habitat conversion
  • Negative effects on natural resources of Green revolution: Intensive use of water, fossil fuels, chemical fertilizers and pesticides (pollution, erosion, salinization and densification)
• Fertilizer Impacts: Inorganic and Organic
  • Inorganic – or industrial fertilizers are mined or synthetically manufactured mineral supplements (nitrogen, phosphors and potassium)
  • Organic – natural materials such as animal manure, crop residues, fresh vegetation, compost
    • Runoffs can lead to phytoplankton blooms and pose human health risks
• Irrigation Impacts
  • Agriculture main reason for extraction and use of fresh water worldwide
  • Efficiency is quite low as only 43% of the water applied gets used by plants
  • Can lead to waterlogging and salinization of soils
  • Drip irrigation is one possible solution
• Monoculture Impacts
  • Large expanse of a single crop
  • More efficient, increases output
  • Devastates biodiversity
  • Susceptible to disease and pests
• Contributes to a narrowing of human diet: 90% of our food comes from 15 crop species and 8 livestock species
• Pesticide Impacts
• Poisons that target pest organism
• Pest organisms pose greater threat in a monoculture situation
• Annual cost of pesticides is about $45 billion
• Concerns about cumulative effects of pesticide use (i.e. killing pest you weren’t intending too)
•  Monoculture and organic fertilizers can cause various fatal impacts on the environment
• Pest = any organism that damages valuable crops - a bigger problem in monoculture.
• Weed = any plant that competes with crops
• Insect, fungi, viruses, rodents and weeds that eat or compete with our crops have taken advantage of the ways we cluster food plants into agricultural fields.
  • Pesticides = positions that target pest organism
  • Insecticides = target insects
  • Herbicides = target plants
  • Fungicides = target fungi
• 91% of pesticides sales are for agricultural purposes
• 85% of pesticides sold in Canada are herbicides
• Usefulness of pesticides tends to decline with time:
  • Pests evolve resistance to pesticides
  • Small fraction of insects and microbes have genes that confer some degree of immunity to a given pesticide
  • If an insect survives pesticide, resistance is passed through their genes to insect offspring.
• Biological control (Biocontrol) = uses a pest’s natural predators to control the pest
• No one can predict the effects of an introduced species
• The agent may have “nontarget” effects on the environment and surrounding economics
• Removing biocontrol agent is harder than halting pesticide use.
• Due to potential problems, proposed biocontrol use must be carefully planned and regulated
• Integrated Pest Management (IPM) – uses multiple techniques to suppress pests
  • Biocontrol
  • Chemical, when needed
  • Population monitoring
  • Habitat alteration
  • Crop Rotation and transgenic crops
  • Alternative tillage methods
  • Mechanical pest removal
• We are critically dependent on insects to pollinate crops
• Male plant sex cells fertilize female sex cells
• 1500 crop species depend on insect pollination (3-8% of global crop populations)
• Pollinators are at risk for various reasons
• Conservation of pollinators is vital
  • Bees devasted by parasites and colony collapse disorder
  • North American farmers regularly hire beekeepers to bring colonies to their fields
  • To conserve bees and other pollinators: reduce or eliminate pesticide use and plat flowering plants
• Genetic Engineering = laboratory manipulation of genetic material
• Creates a genetically modified (GM) organism
• Recombinant DNA = DNA patched together from the DNA of multiple organisms
• Biotechnology = material application of biological science to create products derived from organisms
• Biotechnology has helped us create medicines, clean up pollution, understand the causes of cancer, dissolve blood clots after heart attaches and make better beer and cheese
• Transgenic organism = an organism that contains DNA from another species
• Transgenes = genes that have moved between organisms
• Genetic engineering is like and unlike traditional breeding 
• Similar: 1) both alter gene pools for preferred characteristics and 2) both apply to plants and animals
• Different: 1) traditional breeding uses genes from the same species (selective breeding deals with whole organism, not just genes) and 2) in traditional breeding, genes come together on their own
• Most GM crops today are engineered to resist herbicides, others to resist insects
• Three-fourths of the world’s soybean plants are transgenic
• As are one out of every four corn plants and over half of all cotton plants
• Globally, in 2013, GM foods grew on 175 million hectares of farmland, producing $10.5 billion worth of crops
• Impacts of Gm crops:
• As GM crops expanded, scientists, citizens and policy makers have become concerned because: 1) pests could evolve resistance 2) could ruin the integrity of native ancestral races 3) interbreed with closely related wild plants
• Evidence of negative ecological effect is limited
• Numerous mechanisms whereby genes can “escape”
• Critiques argue that we should adopt the precautionary principle: the idea that one should not proceed until the ramification of an action are well understood
• Debate over GM foods involves more than science 
• Ethical issues play a large role
• People don’t like “tinkering” with “natural” foods (why are we playing god?)
• With increasing GM use, people are forced to use GM products or go to special efforts to avoid them
• Crops that benefit small, poor farmers are not widely commercialized
• The future of GM foods seems likely to hinge on social, economic, legal, political and scientific ones
• Consumers and the government of the worlds developing nations could exert the worlds developing nations could exert the most influence in the end
• India and Brazil approve of GM crops
• China is expanding use of transgenic crops
• Crop diversity provides insurance against failure
• Preserving native variants protects against crop failure
• Genetic diversity in crops has decreased in the last 40/50 years
• Market forces discourage diversity in food’s appearance
• Consumers prefer uniform, standardized food
• Seed Banks = preserve seed types as a living museum of genetic diversity
• Seeds collected and preserve and periodically planted
• Hand pollination preserve genetic distinctiveness
• The Royal Botanic Gardens Millennium Seed Bank in Britain aims to bank 20% if the worlds plant by 2020
• Norway has started a “doomsday vault” seed bank
• As wealth and commerce increase, so does consumption of meat, milk and eggs
• Global meat production has increased fivefold since 1950
• Per capita meat consumption has doubled
• High consumption has led to feedlot agriculture
• Concerted Animal Feeding Operations (Factory Farming) = Huge warehouses deliver energy-rich food to animals living at extremely high densities
• Necessary to keep up with meat consumption in Canada and the United Stated
• Over ½ of the world’s pork and most of the poultry come from feedlots
• Benefits of feedlots: 1) greater production of food 2) keeps up with high meat consumption 3) reduces the impact of livestock on land (use less space) – no overgrazing and soil degradation
• Cons of Feedlots: 1) contribute to water and air pollution 2) poor waste containment may cause human disease (e. coli, salmonella). 3) cattle: steroids used to stimulate growth 4) heavy use of antibiotics to control disease
• 90% of energy is lost every time energy move from one trophic level to the next
• The lower on the food chain from which we take our food sources, the more people the earth can support
• Producing eggs and chicken requires the least space and water; beef requires the most
• Aquaculture = raising aquatic organism for food in a controlled environment (open water pens or land based ponds) and is the fastest growing type of food production (provides a third of the world fish for human consumption).
• Benefits of Aquaculture: 1) reliable protein source 2) sustainable 3) reduces fishing pressure on overharvested wild fish stock 4) energy efficient
• Cons of Aquaculture: 1) diseases can occur, requiring expensive antibiotics 2) reduces food security 3) large amounts of waste 4) farmed fish may escape and introduce diseases into the wild.
• Sustainable Agriculture = does not deplete soil, pollute water or decrease genetic diversity.
• No-till agriculture = depth and frequency of ploughing and tilling is kept to a minimum to protect soil moisture and compaction.
• Low-input agriculture = uses smaller amounts of pesticides, fertilizers, growth hormones, water and fossil fuel energy than industrial agriculture.
• Organic agriculture = uses no synthetic fertilizers, insecticides, fungicides or herbicides (relies on biological approaches – composting and biocontrol).
• Fresh water = relatively pure, with few dissolved salts – only 2.5% of earths water is fresh, most is tied up in glaciers and ice caps
• Water is constantly moving among the reservoirs via the hydrologic cycle
• As water moves through the hydrologic cycle:
  • Stores and distributes heat
  • Erodes mountain ranges
  • Builds river deltas
  • Maintains ecosystems
  • Supports civilization
  • Gives rise to political conflicts
• Residence times = storage time for water
• Reservoirs differ in resident times and amount of water they store
• Climate change will affect the hydrologic cycle:
  • Shift northward in mid-latitude rain belt
  • Earlier snowmelt and spring run off
  • More transpiration
  • Drier summers in the interior continental region
• Additional impacts
  • Warmer rivers (impacting fish)
  • Lower water levels in great lakes
  • Higher ocean water levels
• Tributary = smaller river that flows into a larger
• Drainage basin / watershed = the area of land drained by a river and tributaries
• If there is a large bend in the river, the force of water cuts through the land:
• Oxbow = an extreme bend in a river which can transform into a;
• Oxbow lake = the bend is cut off and remains as an isolated, U-shaped body of water
• Floodplain = areas nearest to the rivers course that are flooded periodically (frequent deposition of silt makes floodplain soils fertile)
• Riparian = riverside areas that are productive and species-rich.
• Wetlands = systems that combine elements of freshwater and dryland
• Freshwater marches = shallow water allows plants to grow above the water’s surface
• Swamps = shallow water that occurs in forested areas (can be created by beavers)
• Bogs = ponds covered in thick floating mats of vegetation (a stage in aquatic succession)
• Wetland > March >
• Wetlands are extremely valuable for:
  • Wildlife
  • Slowing runoff by reducing flooding, recharging aquifers and filter pollutants
  • People have drained wetlands mostly for agriculture
• Southeastern (Potholes region) Canada has lost more than half of their wetlands
• Prairie Pothole Region = an entire region that should have multiple little “prairie potholes” that are ecological diverse havens. They help fertilize the surrounding areas.
• Lakes and ponds are bodies of open, standing water
• Littoral zone = region ringing the edge of a water body
• Benthic Zone = extends along the entire body of the water body (home to many invertebrates)
• Limnetic Zone = open portions of the lake or pond where the sunlight penetrates the shallow waters (I.e. Lake Winnipeg)
• Profundal zone = water that sunlight does not reach (supports fewer animals because there is less oxygen) (i.e. west hawk lake)

• Oligotrophic lake and ponds = have low nutrient and high oxygen conditions – not a lot of primary production going on, very clear lake (i.e. Lake Superior)
• Eutrophic lakes and ponds = have high nutrient and low oxygen conditions (i.e. lake Winnipeg)
• Water bodies fill completely in through the proves of succession
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• Ground water plays key roles in hydrologic cycle
• Confined / artesian = water-bearing, porous rocks are trapped between layers of less permeable substrate – under a lot of pressure (i.e. clay)
• Unconfined aquifer = no upper later to confine it = readily recharged by surface water
• Groundwater becomes surface water through springs or human drilled wells
• Groundwater may be ancient; the average age is 1,400 years
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