1. Soil, Agriculture, and Future of Food
Chapter 7

2. Chapter outline
Feeding 7 Billion-Agriculture Practices, Past, Present and Future
Soil-Structure, Formation, Traits and Agriculture
Keeping Dirt Healthy
Growing Crops

3. Do Now:
Read page on case study and complete a Bubble Map describing Iowa’s Farmers Practice of No-Till Agricuture in notes
For your frame of reference:
Green: Source of information (p )
Blue: Point of View (How has this practice helped the Iowa farmer?)
Red: So what? So Why? (Why is this information/case study important?)

4. Agricultural Practices-Past, Present and Future
Feeding 7 Billion

5. Central Case Study: Iowa’s Farmers Practice No-Till Agriculture
Repeated plowing and planting damage soil
No-till farming benefits soil
Saves time and money
Does not decrease production
Can help make agriculture sustainable
Other conservation measures:
Careful use of fertilizers
Preventing erosion
Retiring fragile soils

6. Today, we produce more food per person
By 2050, we will have to feed 9 billion people
Food production currently exceeds population growth
But not everyone has enough to eat

7. Issues Facing Us Today:
Food security: guarantee of an adequate, safe, nutritious, and reliable food supply
Providing food security to everyone will be one of our greatest challenges
Undernutrition: receiving fewer calories than one’s minimum dietary energy requirements
925 million people do not have enough to eat
Every 5 seconds a child starves to death
Is due to poverty, politics, conflict, and inefficiencies in distribution

8. Food security Indicators of hunger recently increased
After declining for four decades, the number and percentage of hungry people increased in 2008–2009
Higher food prices and the economic slump
The number of undernourished declined in 2010
Hunger levels, as a percentage of population, are lower than in the 1970s

9. Overnutrition and malnutrition
Overnutrition: receiving too many calories each day
Leads to heart disease, diabetes, etc.
In the U.S., 60% of adults are overweight, 25% are obese
Worldwide, over 500 million people are obese
These numbers will rise to 2.3 billion overweight and 700 million obese by 2015
Malnutrition: a shortage of nutrients the body needs
The diet lacks adequate vitamins and minerals
Can lead to diseases

10. Malnutrition can lead to diseases
Kwashiorkor: occurs when diet lacks protein or essential amino acids
Occurs when children stop breast-feeding
Bloated stomach, mental and physical disabilities
Marasmus: is due to protein deficiency and insufficient calories
Wasting of the body
Anemia and deficiency in iodine and vitamin A are also prevalent

11. Biofuels can affect food supplies!
Biofuels: fuels derived from organic materials
Replace petroleum in engines
Ethanol: a biofuel derived from corn
The main biofuel in the U.S.
2007 subsidies doubled U.S. production
Use of corn for biofuel reduced corn supplies
Food prices increased
Farmers sold corn for ethanol, not food
Farmers planted biofuels, not food crops
Riots erupted in many nations

12. Sum up:
What issues are facing us today?

13. Agricultural Practices

14. The changing face of agriculture
10,000 years ago, people in different cultures began to raise plants for food and to domesticate animals
Agriculture: practice of raising crops and livestock for human use and consumption
Cropland: land used to raise plants for human use
Rangeland: land used for grazing livestock
Land devoted to agriculture now covers 38% of Earth’s land

15. The changing face of agriculture
Traditional agriculture: uses human and animal power
Hand tools, simple machines
Polyculture: different crops are planted in one field
Industrial agriculture: uses large-scale machines and fossil fuels to boost yields
Also uses irrigation, fertilizers, and pesticides
Monoculture: planting a single, genetically similar crop
More efficient but reduces diversity, is disease prone
Narrows the human diet
Used in industrial agriculture

16. Seed banks conserve wild genes
Industrial agriculture’s use of genetically similar crops has led to efforts to conserve wild relatives of crops
Wild crops contain genes will will need in the future
Seed banks: institutions that store seed types
Seeds are collected, stored, and periodically planted
Wild crops must not be allowed to interbreed with genetically modified crops
To prevent introduction of GM crops into wild populations

17. The Green Revolution increased yields (Industrial Agriculture)
Green revolution: drastically increased food through new
Technology
Crop varieties
Farming practices
Spread to the developing world in the 1940s
Wheat, rice, corn
Norman Borlaug came up with new wheat crop that was disease resistant and gave high yields
Norman Borlaug won the Nobel Peace Prize for his work

18. The effects of industrialized agriculture (Green Revolution)
Industrial agriculture has allowed food production to keep pace with population growth
But it has many bad environmental and social effects
Benefits: increases crop yields while reducing pressure to develop natural areas for new farms
Drawbacks: water, fossil fuels, fertilizers, pesticides worsen pollution, erosion, and desertification
Requires far more energy than traditional methods
Displaces low-income farmers who can’t afford the technology, forcing them to move to cities (saw in Dirt Movie)

19. Sustainable agriculture
Suitable farmland is disappearing
We must improve the efficiency of production
It is better to raise animals and crops that pollute less, require less fuels, and have less impact on natural systems
Sustainable agriculture: maintains healthy soil, clean water, and genetic diversity
Treats agricultural systems as ecosystems
Low-input agriculture: uses smaller amounts of
Pesticide, fertilizers, growth hormones, antibiotics, water, and fossil fuels than industrial agriculture

20. All About soil

21. Soil: the foundation for agriculture
Soil: a complex system consisting of disintegrated rock, organic matter, water, gases, nutrients, microorganisms
A renewable resource that can be depleted if abused
Soil contains:
Dead and living microorganisms
Decaying material
Bacteria, fungi, worms, insects, burrowing animals
Soil influences ecosystems as much as climate, latitude, and elevation

22. Soil forms slowly Parent material: the base geologic material of soil
Lava, volcanic ash, rock, dunes
Bedrock: solid rock comprising Earth’s crust
Weathering: physical, chemical, and biological processes that form that convert rocks into soil
Biological deposition, decomposition, and accumulation provide organic matter and nutrients
Humus: spongy, fertile material formed by partial decomposition of organic matter
Holds moisture and is productive for plants

23. A soil profile consists of horizons
Horizon: each layer of soil
Soil can have up to six horizons
Soil profile: the cross-section of soil as a whole
Leaching: movement of dissolved particles down through horizons
Can deprive plants of nutrients
Topsoil: inorganic and organic material most nutritive for plants
Vital for agriculture

24. Regional differences in soils affect agriculture
In rainforests, rain leaches minerals and nutrients, reducing their accessibility to roots
Rapid decomposition of leaf litter results in a thin topsoil layer with little humus
Farming quickly depletes the soil’s fertility
Temperate prairies have lower rainfall and less nutrient leaching, resulting in higher fertility

25. Soil Erosion and Degradation

26. Soil erosion Soil degradation: loss of soil quality and productivity
Has caused 13% loss of grain production
Each year, we lose 12–17 million acres of cropland
Erosion, nutrient depletion, water scarcity, salinization, waterlogging, pollution, loss of organic matter
Erosion: transport or removal of material from one place to another
By wind or water
A problem when it happens faster than soil formation
Deposition: dropping out of sediments or arrival of eroded material at a new place

27. Humans make land vulnerable to erosion
Land is made vulnerable to erosion through:
Overcultivating fields – poor planning, excessive tilling
Overgrazing rangeland with too many animals
Clearing forests on steep slopes or with large clear-cuts
Erosion removes valuable topsoil, especially in areas with steeper slopes, greater precipitation intensities, and sparse vegetation

28. Soil erosion is a global problem
Humans are the primary cause of erosion
It is occurring at unnaturally high rates
In Africa, erosion could reduce crop yields by 50% over the next 40 years
The U.S. loses 5 tons of soil for every ton of grain harvested
Degradation of topsoil and decreased crop yields, added to population growth are leading agriculture’s future to a crisis situation

29. Desertification reduces productivity
Desertification: form of soil degradation- loss of more than 10% productivity in soil
Erosion, soil compaction, deforestation, overgrazing
Drought, salinization, water depletion, climate change
Most prone areas: arid and semi-arid lands (drylands)
Desertification endangers the food supply of 1 billion people in over 100 countries
Costing tens of billions of dollars each year
Climate change will worsen desertification by changing rainfall patterns
50 million people will be displaced in 10 years

30. The Dust Bowl In late 1800 and early 1900, farmers and ranchers:
Grew wheat, grazed cattle
Removed native grasses
Dust Bowl: 1930s drought and erosion caused “black blizzards” of sand
Thousands of farmers left their land
Relied on governmental help to survive

31. Soil conservation

32. The Soil Conservation Service (SCS)
Started in 1935 by the Congress, the SCS works with farmers to develop conservation plans for farms
The SCS is now named the Natural Resources Conservation Service
Other countries started their own conservation agencies
No-till farming in Argentina, Brazil, and Paraguay
Grassroots organizations helped by agronomists and government extension agents

33. Protecting soil: crop rotation and contour farming
Crop rotation: growing different crops from one year to the next
Returns nutrients to soil
Prevents erosion, reduces pests
Wheat or corn and soybeans
Contour farming: plowing perpendicularly across a hill
Furrows slow runoff and capture soil

34. Protecting soil: terracing and intercropping
Terracing: level platforms cut into steep hillsides
This “staircase” contains rain and irrigation water
Intercropping: planting different crops in alternating bands
Increases ground cover
Decreases pests and disease
Replenishes soil

35. Protecting soil: shelterbelts and reduced tillage
Shelterbelts (windbreaks): rows of trees planted along edges of fields
Slows the wind
Can be combined with intercropping
Conservation tillage: reduces the amount of tilling
No-till farming disturbs the soil even less

36. Conservation tillage saves soil
Increases organic matter and soil biota
Reducing erosion and improving soil quality
Stores carbon in the soil and reduces fossil fuel use
Minimizes increased use of herbicides and fertilizer
Uses green manure (dead plants as fertilizer) and rotates fields with cover crops
Conservation tillage is used on 40% of U.S. farmland

37. Issues and solutions relating to soil use

38. Overgrazing causes soil degradation
Humans keep over 3.4 billion cows, sheep, and goats
Overgrazing: too many animals eat too much of the plant cover and impede plant regrowth
Soil is degraded and compacted
Increased erosion makes it hard for plants to grow
Non-native plants invade, which are less palatable to livestock and outcompete native vegetation
Ranchers in the western U.S. are finding ways to ranch more sustainably and protect the land’s health
70% of the world’s rangeland is degraded, costing $23.3 billion/year

39. Effects of overgrazing can be striking
Overgrazing sets into motion consequences that degrade soil and grassland ecosystems

40. Agricultural subsidies affect soil degradation
Theoretically, the market should discourage farmers and ranchers from degrading the land
But degradation is slow, and farmers can’t afford to lose money
Many governments spend billions to subsidize agriculture
20% of a U.S. farmer’s income comes from subsidies
Pros of subsidies: protect farmers from uncertain weather
Cons of subsidies: encourage farming of vulnerable land
Producing more food than needed, driving prices down
Farmers should buy insurance against losses

41. U.S. programs promote soil conservation
Conservation Reserve Program (1985): farmers are paid to put highly erodible land in conservation reserves
Trees and grasses are planted instead of crops
Each dollar spent saves 1 ton of topsoil
Generates income for farmers
Improves water quality and provides habitat
$1.8 billion/yr protects 30–40 million acres
The 2008 Farm Bill limits protection to 32 million acres
But funds 14 other programs
International agencies also promote sustainable agriculture

42. Irrigation: productivity with problems
Irrigation: artificially providing water to support agriculture
Unproductive regions become productive farmland
Waterlogging: water suffocates roots in overirrigated soils
Salinization: the buildup of salts in surface soil layers
Worse in dryland areas
Salinization inhibits production of 20% of irrigated cropland, costing over $11 billion/year

43. Sustainable approaches to irrigation
Match crops and climate
Don’t plant water-guzzling crops in dry areas
Plant beans or wheat, not rice
Subsidies make irrigation water artificially cheap
Drip irrigation delivers water directly to plants
Drip irrigation works best on smaller plots with perennial plants (fruit trees)

44. Fertilizers boost yields
Fertilizers: substances containing essential nutrients to enhance crop production
Inorganic fertilizers: mined or synthetically manufactured mineral supplements
Organic fertilizers: the remains or wastes of organisms
Manure, crop residues, fresh vegetation (green manure)
Compost: produced when decomposers break down organic matter

45. Inorganic fertilizers cause problems
Inorganic fertilizers have boosted production
But also severely pollute
Leaching and runoff of inorganic fertilizers causes:
Groundwater contamination
Dead zones in water systems
Air pollution from evaporated nitrates
Inorganic fertilizer use has skyrocketed worldwide

46. Sustainable fertilizers
Sustainable approaches to fertilizing delivers nutrients directly to plant roots and avoids overapplication
Add fertilizers to drip irrigation water
No-till or low-till systems inject fertilizers with seeds
Monitor soil nutrients and add only when they are low
Strips of vegetation along field edges and streams capture nutrient runoff
Organic fertilizers add nutrients and organic matter
Improving soil structure, nutrient and water retention
Integrate inorganic and organic fertilizer systems

47. Pesticides control pests
Pest: any organism that damages valuable crops
Weed: any plant that competes with crops
Pests and weeds especially threaten monocultures
Pesticides: poisons that target pest organisms
Insecticides kill insects, herbicides kill plants, and fungicides kill fungi
75% of pesticides are applied to agricultural land
Exposure to synthetic pesticides can cause health problems for humans and other organisms
Pesticides also kill many nontarget organisms

48. Exit Ticket- on socrative.com
1. How do humans make land vunerable to erosion?
2. What is desertification and give an example?
3. Which method of farming increases ground cover, decreases pests and replenishes soil?

49. Pests, Bugs and their control

50. Pests evolve resistance to pesticides
Pesticides lose effectiveness as pests evolve resistance
Individuals that can metabolize and detoxify a pesticide survive and pass these genes to their offspring
As the population increases, pesticides lose their effectiveness
Pesticide treadmill: chemists increase the toxicity of pesticides to compete with resistant pests
Many species (green peach aphid, diamondback moth) have evolved resistance to multiple chemicals

51. Evolution of pesticide resistance
Over 586 species are resistant to 330 insecticides
Hundreds of weeds and plant diseases have evolved resistance to herbicides and pesticides

52. Biological control (biocontrol)
Biological control: uses a pest’s predators or diseases to control the pest
But organisms can’t be easily controlled
Organisms can harm nontargets
Example: introduced cactus moths eat rare Florida cacti
Biocontrol must be carefully planned and regulated

53. Integrated pest management (IPM)
Techniques to suppress pests include:
* Biocontrol * Habitat alteration
* Chemicals, if necessary * Crop rotation
* Population monitoring * Transgenic crops
* Alternative tillage methods
* Mechanical pest removal
IPM in Indonesia increased rice yields 13% and saved $179 million/yr in phased-out subsidies

54. Pollinators are beneficial “bugs”
Not all insects are pests; some are absolutely vital
Over 800 cultivated plants rely on pollinators
Pollination: male plant sex cells fertilize female sex cells
Flowers are evolutionary adaptations to attract pollinators
Nectar, pollen, sweet smells, bright colors
U.S. bees provide $3 billion/year in pollination services, but parasitic mites decimated populations
Beekeepers were driven to financial ruin

55. Conservation of pollinators is vital
Populations of bees further plummeted in 2006
Colony collapse disorder: entire beehives have died
One-third of all U.S. honeybees die/year
Unknown causes—Insecticides? Parasites? Stress?

56. Future of Food
GMOS, Aquaculture

57. Genetically modified food
Despite the Green Revolution, relentless population growth demands more innovation to feed us
Scientists alter genes of organisms
Crop plants and livestock
Genetically modified organisms enhance nutrition and agricultural efficiency
But the risks are not well understood, leading to anxiety and protest from:
Consumer advocates, small farmers, environmentalists, critics of big business

58. Genetically modified organisms
Genetic engineering: laboratory manipulation of genetic material
Add, delete, modify DNA
Genetically modified (GM) organisms: organisms that have been genetically engineered using …
Recombinant DNA: DNA created from multiple organisms

59. Biotechnology is impacting our lives
The goal of genetic engineering: put genes that code for desirable traits (rapid growth, nutrition, etc.)
Into organisms lacking those traits
Transgenic organism: an organism that contains DNA from another species
Transgenes: the genes that have moved between organisms
Biotechnology: the application of biological science to create products derived from organisms
It has created medicines, cleaned up pollution, dissolved blood clots, and made better food

60. Some genetically modified foods

61. Selective breeding vs. genetic engineering
Selective breeding: changes organisms through selective breeding of the same or similar species
Works with organisms in the field
Genes come together on their own
Uses the process of selection to change organisms
Genetic engineering: mixes genes of different species (e.g., spiders and goats)
Works with genetic material in the lab
Directly creates novel combinations of genes
Resembles the process of mutation

62. Biotechnology is changing our world
GM foods are a big business
Most GM crops are herbicide and pesticide resistant
Large-scale farmers grow crops more efficiently
Most U.S. corn, soybeans, and cotton are genetically modified

63. What are the impacts of GM crops?
As GM crops expanded, citizens, scientists, and policymakers became concerned that:
GM crops could have adverse impacts on human health
Pests could evolve resistance and become “superpests” and “superweeds”
GM crops could harm nontarget organisms
GM crops could interbreed with closely related wild plants
Millions of Americans eat GM foods without obvious harm
But it is too early to dismiss concerns

64. Some impacts of GM crops
Mixed results on pesticide use
Insecticide use declined, but herbicide use increased
GM foods can advance sustainable agriculture
Grown with no-till farming
Drought resistant and high-yielding
Problems with GM foods:
Expensive
Little incentive to develop crops for small-scale farmers

65. Genetic engineering is profit driven
This “gene revolution” is driven by financial interests of corporations
A few large agribiotech corporations dominate the world’s food supply
Europeans want GM foods labeled
U.S. consumers have mostly accepted GM crops
Brazil, India, and China are aggressively pursuing GM crops
We should follow the precautionary principle and proceed with caution on GM foods

66. Consumption of animal products is growing
As developing nations become wealthier, meat consumption will double by 2050
As wealth and commerce increase, so does consumption of meat, milk, and eggs
Since 1950, global meat production has increased fivefold, and per capita meat consumption has doubled

67. Our food choices are also energy choices
Eating meat is far less energy efficient than eating crops
90% of energy is lost from one trophic level to the next
Some animals convert grain into meat more efficiently than others

68. Resources needed for livestock production
Land and water are needed to raise food for livestock
Eggs and chicken meat require the least
Producing beef requires the most
When we choose what to eat, we choose how we use resources

69. Feedlot agriculture
Feedlots (factory farms): also called concentrated animal feeding operations (CAFOs)
Huge warehouses or pens deliver food to animals living at extremely high densities
House over half of the world’s pork and most of its poultry
Most U.S. meat is raised in feedlots, which use liberal amounts of antibiotics to control disease

70. Pros and cons of feedlot agriculture
It allows greater production of affordable meat
It reduces grazing impacts on the land
45% of the world’s grain is fed to livestock
Endangering food security for the world’s poor
Feedlots produce huge amounts of manure and urine
Can pollute surface water and groundwater
Crowded housing causes outbreaks in disease
Heavy use of antibiotics
More greenhouse gases (CO2, methane, nitrous oxides) than automobile emissions

71. We raise seafood with aquaculture
World wild fish populations are plummeting
Increased demand and technology
Aquaculture: raising aquatic organisms in a controlled environment
Open-water pens or land- based ponds
The fastest-growing type of food production
Most widespread in Asia

72. Aquaculture’s benefits and drawbacks
Reduces pressure on overharvested wild fish
Uses fewer fossil fuels, is safer, and produces more fish than commercial fishing
Drawbacks:
Lots of waste produced
Uses grain, which affects food supplies for people
Fish meal is made from wild ocean fish
Escaped fish introduce disease or outcompete wild fish

73. Organic agriculture
Sustainable agriculture keeps high crop yields, minimizes resource use, and decreases environmental impacts
Organic agriculture: uses no synthetic fertilizers, insecticides, fungicides, or herbicides
Organic Food Production Act (1990) establishes national standards for organic products
The USDA issued criteria in 2000 by which food could be labeled organic
California, Washington, Texas passed stricter guidelines for labeling

74. Benefits and costs of organic farming
Farmers have lower input costs, enhanced income, reduced chemical pollution and soil degradation
Obstacles include the risks and costs of switching to new methods
The main obstacle to consumers is the higher price
But many are willing to pay the price
Worldwide, sales surpassed $54 billion

75. Organic agriculture is booming
U.S. consumers spent $24.8 billion on organic food in 2009
U.S. land devoted to organic agriculture has quadrupled since the mid- 1990s

76. Governments can support organic farming
The U.S Farm Bill gives $112 million over 5 years for organic agriculture
It helps defray certification costs
In 1993, the European Union started supporting farmers financially during conversion to organic farming
Reduced inputs and higher market prices will make it as profitable as conventional methods

77. Locally supported agriculture is growing
Sustainable agriculture reduces fossil fuel use from long-distance transport of products
The average U.S. food product travels 1,400 miles
Farmers’ markets: provide fresh, locally grown food
Provide organic items and unique local varieties
Community-supported agriculture (CSA)
Consumers pay farmers in advance for produce
Consumers get fresh food
Farmers get a guaranteed income

78. Sustainable agriculture: a roadmap for the future
Sustainable agriculture mimics natural ecosystems
They operate in cycles and are internally stabilized by negative feedback loops
Agricultural systems can be integrated with the surrounding ecosystems
Reducing environmental impacts from food production
Making agriculture sustainable is crucial for all of us

79. Conclusion
Industrialized agriculture has had substantial negative environmental consequences
To support 9 billion humans, we must shift to sustainable agriculture to prevent further land degradation
Biological pest control, organic agriculture
Pollinator protection, preservation of native crops
Aquaculture
Careful, responsible genetic modification of food 79