Chapter 8: Agriculture and Biotechnology

The Race to Feed the World

  • Agriculture – The practice of raising crops and livestock for human use and consumption
  • We obtain most food, fibre, and biofuels from cropland – the land used to raise plants, and rangeland – the land used for grazing livestock

Agriculture First Appeared 10000 Years Ago

  • After glaciation, people in some cultures began to cultivate (raise plants from seeds) and domesticate animals as a source of food and labour
  • Agriculture is a form of intensification – A way to increase the productivity and carrying capacity of a given unit of land
  • Traditional agriculture – Cultivating, harvesting, storing, and distributing crops by human and animal muscle power, hand tools, and simple machines
  • Subsistence agriculture – Oldest form of traditional agriculture where farming families only make enough food for themselves and do not use large scale irrigation, fertilizer, farm machinery, or animal labor.


Industrialized Agriculture More Recent

  • Introduced large scale mechanization and fossil fuels to agriculture field replacing horses and oxen with technology
  • Facilitated irrigation and fertilization
  • Requires that vast fields be planted with single types of crops.
  • This uniform planting of a single crop type over a large expanse of land, termed monoculture, is distinct from the traditional approach.

We Are Producing More Food Per Person

  • Almost a billion people don’t have food to eat
  • Goal is for food security – The guarantee of an adequate and acceptable food supply to all people at all times
  • The worlds soil is in decline, a significant portion of the planets arable land – land that is suitable for annual planting of crop, has already been brought into production


5 A’s of Food Security

  1. Availability (production)
  2. Adequacy (quality)
  3. Accessibility (storage, distribution infrastructure, civil unrest, social status)
  4. Affordability (ability to import, buy, produce, subsidize)
  5. Acceptability (cultural, religious)


Undernourishment, Over nutrition, and Malnutrition

  • Although many people lack access to food, others are affluent enough to consume more than is healthy
  • People who are undernourished, receive less than 90% of their daily caloric needs
  • In the developed word, many people suffer from over nutrition, taking too many calories each day
  • Malnutrition – Unbalanced diet (shortage or excess of required nutrients)
  • Kwashiorkor –Bloating of the abdomen, deterioration and discolouration of hair, mental disability, anemia, immune suppression, developmental delays, and reduced growth in children
  • Marasmus – Causes wasting or shrivelling among millions of children in the developing world


Green Revolution

  • Technological advances allowed farmers to dramatically increase yields per hectare of cropland and helped millions of people avoid starvation
  • Better farming methods to alleviate world hunger
  • Started in Mexico in 1940s
  • Increased yields via selective breeding
  • Spread to India and Pakistan and then rest of the world
  • GR promised to:
  • Increase yields
  • Increase carrying capacity
  • Improve technological knowledge
  • Eliminate hunger
  • Goals were approached through both intensification and extensification of agricultural production
  • Extensification – More land brought into production
  • Intensification – Greater yields per unit land


Impacts of Green Revolution

Negative impacts

  • Pesticides, irrigation, fertilizers, new strains are a mixed blessing
  • Salinization, desertification, pollution, loss of arable land
  • Overgrazing, over exploitation of arable land, over pumping rives and aquifers
  • Monoculture increased yield but reduced biodiversity (pollinators) and less disease resistance
  • Involved increases in cultivated land
  • Not all farmer have access to land, training, credit, technologies, inputs

GR Increased Use of Irrigation

Improved technologies

  • Efficient electric pumps, drip systems
  • More water directly to plant roots

Results

  • Dry-season planting (multiple cropping)
  • Minimize impacts of drought
  • Cultivation of previously non-arable land
  • Drip irrigation targets water directly to plants

GR Increased Use of Fertilizers

  • Limiting resource - nutrient in shortest supply
  • Synthetic fertilizers can remove these limitations
  • Fertilizers boost yield but cause problems
  • 10–60% of added N ends up in plants; rest is transformed or lost (leaching, runoff, volatilization)
  • Added nutrients do not proportionally lead to more primary production or crop yield
  • Nitrate in drinking water is toxic (oxidizes hemoglobin)
  • Produces carcinogens
  • Fertilizer runoff causes pollution downstream (algal blooms, eutrophication)


GR Increased Use of Pesticides

  • Pests and weeds - organisms occurring where they are not wanted
  • Compete with crops, damaging to human interests
  • Thousands of pesticides have been developed (herbicides, insecticides, fungicides)
  • 85% of pesticides sold in Canada are herbicides
  • Results: decreased crop loss, increased food quality

Problems:

  • Many are neurotoxic (developed as chemical weapons)
  • Can affect non-target organisms, including humans
  • End up in waterways
  • Pests can evolve so that they are resistant to pesticides


GR Increased Use of Machines

  • Ability to farm much larger acreage \rightarrow extensification
  • Greater use of fossil fuels
  • Fewer personnel
  • Monocultures


GR Involved Development of New Cultivars

  • Cultivars - variety of plant that has been intentionally selected for
  • More plant energy into growth of grain instead of leaves or stem
  • Early-maturing \rightarrow multiple harvests
  • More uniform \rightarrow easier mechanized harvesting
  • Better response to fertilizers
  • Drought-resistant, pest-resistant


Bio-Fuel Production

  • Fuel derived from recently dead biological material
  • Wood fuels, crop waste, energy-from-waste, etc.
  • Usually from crops high in sugar or oils


Problems of Extensification & Intensification Livestock:

  • Consumption of animal products increases with wealth
  • Livestock production accounts for 70% of all agricultural land and 30% of Earths surface
  • “The livestock sector emerges as one of the top 2 or 3 most significant contributors to the most serious environmental problems, at every scale from local to global.”
  • 70% of previously forested land in Amazon is now pastured for livestock.
  • Livestock are responsible for 18% of greenhouse gas emissions (more than transport sector)
  • “Probably” largest source of water pollution (wastes, antibiotics & hormones; fertilizers & pesticides for feed crops; sediment from eroded pastures; chemicals from tanneries)
  • In US: 55% of erosion & sediment; 37% of pesticide use; 50% of antibiotic use; 33% of N & P loading of freshwater systems


Food Choice Effects on Energy, Water & Land

  • Our Food Choices are also energy, water, and land use choices
  • 90% of energy is lost every time energy moves from one trophic level to the next
  • The lower on the food chain we eat, the more people Earth can support
  • Meat is much less energetically efficient than grain as a source of food calories

Meat Consumption

  • Increased meat consumption has led to feedlot agriculture
  • Feedlots – Huge warehouses deliver energy rich foods to animals living at extremely high population densities
  • Factory Farms – Over half of the worlds pork and poultry come from feedlots, and much of the beef
  • CAFO – Concentrated Animal Feeding Operation

CAFO

  • A production process that concentrates large numbers of animals in relatively small and confined places, and that substitutes structures and equipment (for feeding, temperature controls, and manure management) for land and labour

Benefits

  • Faster & greater production of food
  • Uses less space

Drawbacks

  • Major sources of water and air pollution
  • Waste containment issues may cause human disease
  • Antibiotics & hormones
  • Ethical?


Pollination

  • Plant fertilization
  • We depend on insects to pollinate crops
  • Value of insect pollination services in Canada is $1.2 billion
  • Globally, one mouthful in three requires insect pollination


Impacts on Soil

  • Compacts, exposes soil
  • Disrupts sub-surface ecology


Mechanization & Monoculture

  • Go hand-in-hand
  • More efficient, increases output
  • Devastates biodiversity
  • 90% of our food comes from 15 crop species and 8 livestock species
  • Renders crops susceptible to disease and pests

Preservation of Crop Diversity

  • Is extremely important
  • Mechanization and market forces discourage diversity in food
  • Consumers prefer uniform, standardized food


Seed Banks

  • Living museums
  • Seeds are collected, preserved & periodically planted
  • Hand pollination preserves genetic diversity
  • Global Crop Diversity Trust
  • Svalbard Global Seed Vault (“doomsday vault”)

GMO (Genetically modified organism)

  • Is transgenic
  • Contains a gene inserted into its genome from a different organism to achieve a desired trait
  • Recombinant DNA
  • DNA patched together from the DNA of multiple organisms

Selective breeding

  • Genetic engineering differs from traditional selective breeding
  • Selective breeding is select phenotype (indirectly selects for certain alleles)


Splicing Genes Together

  • Employing genetic engineering, researchers can take certain genes from a source organism and put them into another plant or animal

Example

A gene that prevents rotting in beans might be spliced into tomatoes

  • Tomato looks and tastes like an unaltered tomato, but is resistant to rotting
  • GMOs are engineered for pest resistance, herbicide resistance, delayed ripening, better storage, etc.
  • Higher yield, less waste, more nutritious, etc.

Unintended Environmental Consequences

  • Depletion of groundwater
  • Soil nutrient depletion from monoculture
  • Salinization by irrigation
  • Erosion from mechanization
  • Pollution from agrochemicals
  • Increased energy use
  • Pesticide-resistant pest species
  • Controversy over genetic engineering
  • Genetic uniformity, loss of biodiversity


Sustainable Agriculture

Involves:

  • Recognizing physical/ hydrological limits to productivity
  • Minimizing negative impacts of: intensive production & irrigation, monoculture, mechanization, fertilizers, pesticides, growth hormones, and other agri-chemicals
  • Multi-cropping, crop rotation
  • Minimum tillage
  • Soil conservation
  • Preservation of traditional seeds
  • Agroforestry
  • Urban agriculture
  • Properly designed irrigation
  • Integrated pest management
  • Agricultural extension, training
  • Land tenure & credit availability
  • Better distributional infrastructure


Aquaculture

  • The farming of aquatic organisms in inland and coastal area, involving intervention in the rearing process to enhance production and the individual or corporate ownership of the stock being cultivated.
  • Includes fish, molluscs, crustaceans, aquatic plants (567 species worldwide)
  • Marine (Mariculture) or inland (usually freshwater)
  • Inland aquaculture is growing faster than marine (mostly in developing world)
  • Fastest-growing food production sector
  • Accounts for ~50% of all fish used for food
  • Fish makes up 17% of the global population’s intake of animal protein
  • Per capita fish consumption has doubled since 1960
  • Fish are used for many other non-food uses
  • Increase in aquaculture is a response to declining wild fisheries


Fully Exploited

  • Means that we are taking all the excess that is being produced but knowing they could still reproduce


Over Exploited

  • Taking them all when they cant reproduce

Fish Farming

  • Most common form of aquaculture
  • Cultivation of fish for commercial purposes in man-made tanks and other terrestrial enclosures
  • Most common types of farmed fish are catfish, tilapia, salmon, carp, cod and trout
  • Catfish and tilapia (are easy to raise, they have no specifications)

Closed Pond Systems

  • Covered to allow for control of light and temperature, limit predator access
  • Usually smaller in scale than open ponds


Mariculture

  • Cultivation of marine organisms in the open ocean, an enclosed portion of the ocean, or tanks or ponds filled with seawater
  • Fish (e.g, salmon and flounder) - shellfish (e.g. shrimp and oysters), sea plants (e.g. kelp and seaweed), corals
  • Products are used for cosmetics, jewelry (e.g. cultured pearls), fish meal


Demands on Ecosystem Services

  • Low-intensity aquaculture has low yields
  • Example \rightarrow shrimp 0.1 kg m-2 y-1
  • Intensive modern aquaculture yields \rightarrow 4 kg m-2 y-1
  • 50-60X the most productive river
  • At $20/kg wholesale, value of sales \rightarrow $800,000/ha-2y-1


Aquaculture Density

  • Wild populations don’t grow at aquaculture densities
  • Density and productivity of food rarely occurs
  • Nutrients can’t be supplied & waste products cannot be removed at sufficient rates
  • Predators will focus on such dense accumulations
  • Dense populations transmit disease very quickly
  • Intensive energy outputs are required


Environmental Problems with Mariculture

  • Wastes from cage cultures
  • Drugs, hormones, parasiticides
  • Farm escapees and invasive
  • Genetic pollution
  • Disease and parasite transfer
  • Habitat modification
  • Using wild-caught fish to feed farmed fish puts additional pressure on these populations
  • Affects other populations that depend on them for food
  • Escaped fish compete for food and habitat; transmit disease
  • Prey on and breed with local fish
  • Fact that they are transgenic can cause significant problems
  • Fish waste adds nutrients, leading to eutrophication
  • Uneaten food can build up on ocean floor, altering biota
  • Diseases, pathogens, parasites
  • Optimal conditions for transmission in crowded pens
  • Alters natural behaviour


Improvements on the Horizon

  • New species, genetic engineering improved techniques
  • Substitutes for fish meal
  • More efficient use of food
  • Rearing, not capturing early life stages
  • Refined use of chemicals
  • Multi-species rearing
  • Better recognition of and regulation of demands on ecosystem services


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