food soil n.
Skip this Video
Loading SlideShow in 5 Seconds..
Food & Soil PowerPoint Presentation
Download Presentation
Food & Soil

Loading in 2 Seconds...

play fullscreen
1 / 73

Food & Soil - PowerPoint PPT Presentation

  • Uploaded on

Food & Soil . Chapter 14 & 16. Perennial crops . Return yearly No need to prepare soil Advantages-less labor; reduces soil erosion; deeper roots mean less need for irrigation; less pollution from chemical fertilizers & pesticides. Land Institute in Kansas.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

Food & Soil

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
food soil

Food & Soil

Chapter 14 & 16

perennial crops
Perennial crops
  • Return yearly
  • No need to prepare soil
  • Advantages-less labor; reduces soil erosion; deeper roots mean less need for irrigation; less pollution from chemical fertilizers & pesticides
land institute in kansas
Land Institute in Kansas
  • Experimenting with ecology approach to agriculture
  • Polyculture- perennial grasses, legumes, sunflowers, grain crops, & plants that provide natural insecticides
food providers
Food Providers
  • Croplands – grains
  • Rangelands – meat
  • Ocean fisheries
industrialized agriculture
Industrialized agriculture
  • High-input
  • Uses large amounts of fossil fuel energy, water, commercial fertilizers, pesticides
  • Monoculture
plantation agriculture
Plantation Agriculture
  • Form of industrialized
  • Tropical developing countries
  • Cash crops (bananas, coffee, soybeans, sugar cane, cocoa, vegetables)
  • Monoculture
traditional subsistence ag
Traditional Subsistence Ag
  • Uses human labor or draft animals
  • Produces enough crops or livestock for family
traditional intensive ag
Traditional Intensive Ag
  • Increased input of human & draft labor, fertilizers, & water
  • Produces food for family & to sell for income
green revolution
Green Revolution
  • Develop & plant monocultures- selectively bred or genetically engineered key crops (rice, wheat, corn)
  • Produce high yields by high inputs of fertilizers, pesticides, water
  • Multiple cropping- increase number of crops grown per year on a plot of land

1st Green Revolution- high input approach 1950 – 1970

  • 2nd Green Revolution- since 1967, fast-growing dwarf varieties of rice & wheat
more food less land
More Food, Less Land
  • Saves large areas of forests, grasslands, wetlands, & easily eroded mountain terrain from being used to grow food
agricultural industry
Agricultural Industry
  • Superfarms- big companies & larger family-owned farms control 75% of US food production
  • Production has doubled since 1950
  • More efficient- input decreases, output increases
  • US farm products cost 1/3 less than in 1910
  • Energy- 10 units / 1 unit of food on the table
  • Practice of growing several crops on the same plot

polyvarietal cultivation
Polyvarietal Cultivation
  • Plot contains several varieties of same crop
  • 2 or more different crops at the same time on a plot
  • Alley cropping
  • Crops & trees are grown together
  • Different plants maturing at various times are planted together
  • Of low-input polyculture
    • Less need for fertilizer
    • Less need for water
    • Protection from erosion
    • Less need for insecticides
    • Less need for herbicides
    • Insurance against profit loss
  • Soil replenishment & crop growth
    • Plant corn & trees at start of growing season
    • Cut trees at start of 2nd growing season
    • Add phosphate rock
    • Plant leaves & stems (waste) of Mexican sunflower – provides nutrients
soil erosion
Soil Erosion
  • Movement of soil components (surface litter & topsoil)
  • Causes:
    • Farming, logging, construction, overgrazing, off-road vehicles, deliberate burning
  • Effects:
    • Loss of soil fertility
    • Sediment in surface water
farm act
Farm Act
  • Food Security Act 1985
  • Subsidy for taking erodible land out of production
  • Replant with grass or trees for 10-15 years
dust bowl
Dust Bowl
  • Wind erosion
  • Crop failure
  • Extensive drought
  • Started soil conservation practices
  • Conversion of usable land to desertlike land
    • 1/3 of all land
    • 70% of drylands
  • Prevention (or slowing)- reduce overgrazing, deforestation & destructive forms of planting, irrigation, & mining
causes of desertification
Causes of desertification







Soil compaction

Natural climate


Worsening drought


Economic losses

Lower living




Figure 14-10Page 283

irrigation issues
Irrigation Issues
  • Salinization- accumulation of salts in upper soil layers from annual applications of irrigation water
    • Reduces yield on 1/5 of cropland
  • Waterlogging- saturation of soil with irrigation water
    • Water table rises closer to surface
    • Reduces yield on 1/10 of cropland


Figure 14-12

Soil Salinization



Flushing soil

(expensive and

wastes water)

Not growing crops

for 2-5 years

Installing under-

ground drainage

systems (expensive)

Reduce irrigation

Switch to salt-

tolerant crops

(such as barley,

cotton, sugar beet)

soil conservation
Soil Conservation
  • Using methods to reduce soil erosion & restore soil fertility
  • Conventional tillage farming- farmers plow, break up, then smooth soil for planting surface
    • Often leaves soil bare

Conservation tillage farming- disturbs soil as little as possible while planting crops

    • Minimum tillage- soil not disturbed over winter
    • No till- special planting machines inject seeds, fertilizers, & weed killers into thin slits in unplowed soil, cut is smoothed over
figure 14 13
Figure 14-13


Conservation Tillage



Can increase

herbicide use for

some crops

Leaves stalks that

can harbor crop

pests and fungal

diseases and

increase pesticide




in expensive


Reduces erosion

Saves fuel

Cuts costs

Holds more soil


Reduces soil


Allows several crops

per season

Does not reduce

crop yields

Reduces CO2

release from soil

reducing soil erosion
Reducing Soil Erosion
  • Terracing- cutting series of steps into a hillside
    • Retains water at each level = controls runoff

Control farming- plowing/planting crops across slope (instead of up & down)

    • Each row holds soil & slows water runoff
  • Strip cropping- plant alternating strips of a row crop (cotton/corn with grass/legume)
    • Cover crop traps soil = slows erosion & spread of pests/disease

Alley cropping (agroforestry)- several crops plants in strips between trees & shrubs (used for fruit or fuel wood)


Land classification- identify easily erodible land

    • Suitable/unsuitable for cultivation
  • Organic fertilizer- using plant/animal materials to restore nutrients
  • Commercial inorganic fertilizer- produced from minerals


Inorganic Commercial Fertilizers



Easy to transport

Easy to store

Easy to apply

Inexpensive to produce

Help feed one of every

three people in the


Without commercial

inorganic fertilizers,

world food output could

drop by 40%

Do not add humus to soil

Reduce organic matter

in soil

Reduce ability of soil to

hold water

Lower oxygen content of


Require large amounts of

energy to produce,

transport, and apply

Release the greenhouse

gas nitrous oxide (N2O)

Runoff can overfertilize

nearby lakes and kill fish

Figure 14-15Page 286

organic fertilizers
Organic Fertilizers
  • Animal manure- dung & urine of cattle, horses, poultry, other farm animals
    • Adds organic nitrogen
    • Stimulates soil bacteria & fungi
  • Green manure- freshly cut or growing green vegetables plowed into soil
    • Increases organic matter & humus
  • Compost- formed when (oxygen &) microorganisms in soil break down organic matter (leaves, food wastes, paper, wood)

Spores of mushrooms- (puffballs & truffles) take in moisture & nutrients

    • One application lasts all year
crop rotation
Crop Rotation
  • Plant areas with nutrient-depleting crops then legumes the next year
    • Restores nutrients
    • Reduces erosion by keeping soil covered
    • Reduces crop losses to insects
nutrition problems
Nutrition Problems
  • Chronic undernutrition- cannot grow or buy enough food to meet basic energy needs
    • Mental retardation
    • Stunted growth
    • Susceptible to infectious diseases (diarrhea, measles)
  • Malnutrition- results from deficiencies of protein & key nutrients
from malnutrition
From Malnutrition
  • Marasmus- diet low in calories & protein
    • Nursing infants of malnourished mothers
    • Children who don’t get enough food after being weaned
    • Thin, shriveled (looks like a very old miniature starving person)
    • Effects can be reversed with balanced diet

Kwashiorkor- severe protein deficiency in infants & children (1-3)

    • New baby deprives them of breast milk
    • Diet changes to grain or sweet potatoes (enough calories, not enough protein)
    • Bloated belly, reddish-orange hair, discolored/puffy skin
    • Effects can be cured with balanced diet
    • EXCEPT- mental retardation & stunted growth
  • 825 million- 95% in developing countries
  • 5.5 million premature deaths
reducing deaths
Reducing Deaths
  • Immunize children
  • Encourage breast feeding
  • Prevent dehydration (from diarrhea)
  • Prevent blindness in children (Vitamin A)
  • Family planning services
  • Increase education for women
  • Vitamin A- blindness, death
  • Iron- anemia, fatigue, increased chances of infection, increased chance of dying in childbirth, infant- increased chances of death due to infection
  • Iodine- stunted growth, mental retardation, goiter (enlargement of thyroid gland that can lead to deafness)
  • Food energy intakes exceed energy use & causes excess body fat
  • Harmful effects:
    • Lower life expectancy
    • Greater susceptibility to disease & illness
    • Lower productivity
    • Lower life quality
  • 2/3 of US adults are overweight
  • 1/3 obese
china s food problems
China’s Food Problems
  • Falling grain production
  • Rise in meat consumption
  • Large (potential) food supply deficit
figure 14 19 page 292
Figure 14-19Page 292


Genetically Modified Food and Crops





Need less fertilizer

Need less water

More resistant to insects,

plant disease, frost, and


Faster growth

Can grow in slightly salty


Less spoilage

Better flavor

Less use of conventional


Tolerate higher levels of

pesticide use

Higher yields

Irreversible and

unpredictable genetic

and ecological effects

Harmful toxins in food

From possible plant cell


New allergens in food

Lower nutrition

Increased evolution of


Insects and plant


Creation of herbicide-

Resistant weeds

Harm beneficial insects

Lower genetic diversity

limits to increased food production
Limits to Increased Food Production
  • Requires huge amounts of fertilizer & water to increase yield
  • High cost
  • Decreased yields due to soil erosion & loss of fertility
  • Irrigated soil becomes salty & waterlogged
  • Underground & surface water becomes depleted & polluted with pesticides & nitrates
  • Population of rapidly breeding pests develop genetic immunity to pesticides
types of new food
Types of New Food
  • Winged bean
    • Fast growing
    • Many edible parts
    • Needs little fertilizers (nitrogen-fixing root nodules)
  • Microlivestock- edible insects
    • Potential sources of protein, vitamins, minerals
    • Black ant larvae
    • Giant waterbugs
    • Emperor moth caterpillars
    • Cockroaches

problems with new foods
Problems with New Foods
  • Convincing farmers to take financial risk
  • Convincing consumers to try new foods
food production
Food Production
  • 40% of food production


  • 2/3 of rice & wheat
  • Come from 20% of irrigated croplans

Good news- irrigated area has grown 3x

Bad news- population is growing faster

increasing irrigated land
Increasing Irrigated Land
  • Tropical forests & arid land = poor soil fertility, steep slopes
  • Unlikely to be sustainable if cultivated
  • Irrigation would require expensive dams
  • Large inputs of fossil fuels to move water
  • Groundwater depletion
  • Expensive to stop:
    • Erosion
    • Groundwater depletion
    • Salinization
    • Waterlogging
urban areas
Urban Areas
  • Grow more food in urban areas like:
    • Empty lots
    • Backyards
    • Rooftops
    • Balconies
food wastes
Food Wastes
  • 70% of food is wasted
    • Spoilage
    • Inefficient processing & preparation
    • Plate waste
meat production
Meat Production
  • Rangeland- grasslands in temperate & tropical climates that supply forage or vegetation for grazing or browsing animals
  • Pasture- managed grasslands or enclosed meadows usually planted with domesticated grasses or other forage
  • Renewable grasslands- as long as only upper ½ is eaten (grasses grown from base, not tip); can be grazed again & again
environmental effects
Environmental Effects
  • Animal waste may contaminate groundwater or nearby streams
  • Smell
  • Increased demand for feed (grain)
  • Too many animals graze too long & exceed the carrying capacity of grassland area
    • Lowers net primary productivity
    • Reduces grass cover
    • Prolonged drought may lead to desertification
sustainable rangeland management
Sustainable Rangeland Management
  • Move to another grazing area
  • Fence off riparian areas
  • Provide supplemental feed at selected sites
  • Fisheries- concentrations of particular aquatic species suitable for commercial harvesting in ocean area or inland body of water
  • Aquaculture- raising marine & freshwater fish like livestock in ponds, underwater cages, & from inland freshwater fishing (from lakes, rivers, reservoirs, ponds)
  • 7% of global food supply; 55% from fisheries
fishing methods
Fishing Methods
  • Trawling- dragging funnel-shaped net along ocean bottom
    • Shrimp, cod, flounder, scallops (seals, sea turtles)
  • Purse-seine- large net is closed around feeding school near surface
    • Tuna, mackerel, anchovies, herring (dolphins)
  • Longlining- line with many hooks (80 miles long with thousands of hooks)
    • Swordfish, tuna, shark, halibut, cod (sea turtles)
  • Driftnet- huge drifting nets (overfishing)
figure 14 24
Figure 14-24

Spotter airplane



Fish farming

in cage



trawl flap




fish school

trawl bag

fish caught

by gills

Drift-net fishing



Long line fishing

lines with


  • Overfishing- too little breeding stock is left to maintain population
  • Commercial extinction- caused by prolonged overfishing; species no long profitable to hunt
  • Overfishing + habitat degradation = 14 major commercial fish species have been severely depleted
other methods
Other Methods
  • Fish farming- cultivating fish in a controlled environment & harvesting them at desired size
  • Fish ranching- hold species (like salmon) in captivity & releasing them to spawn, adults ar then harvested





Highly efficient

High yield in small

volume of water

Increased yields

through cross-

breeding and genetic


Can reduce over-

harvesting of

conventional fisheries

Little use of fuel

Profit not tied to price

of oil

High profits

Large inputs of land, feed,

And water needed

Produces large and

concentrated outputs of


Destroys mangrove forests

Increased grain production

needed to feed some


Fish can be killed by

pesticide runoff from

nearby cropland

Dense populations

vulnerable to disease

Tanks too contaminated to

use after about 5 years

Figure 14-27



More Sustainable Aquaculture

  • Reduce use of fishmeal as a feed to reduce depletion of other fish
  • Improve pollution management of aquaculture wastes
  • Reduce escape of aquaculture species into the wild
  • Restrict location of fish farms to reduce loss of mangrove forests and other threatened areas
  • Farm some aquaculture species (such as salmon and cobia) in deeply submerged cages to protect them from wave action and predators and allow dilution of wastes into the ocean
  • Set up a system for certifying sustainable forms of aquaculture

Figure 14-28

food production policy
Food Production Policy
  • Price controls
    • + low prices for consumers
    • - loss of income for farmers
  • Subsidies & tax breaks
    • + reduces money used as incentives
    • - may produce more than can be sold
  • Eliminate price controls & subsidies
    • + uses $ to reward conservation
    • - increase in food prices


Sustainable Agriculture



Soil erosion

Soil salinization

Aquifer depletion



Loss of


Loss of prime


Food waste

Subsidies for unsustainable

farming and fishing

Population growth


High-yield polyculture

Organic fertilizers

Biological pest control

Integrated pest


Irrigation efficiency

Perennial crops

Crop rotation

Use of more water-

efficient crops

Soil conservation

Subsidies for more sustainable farming and


Figure 14-29

moving to sustainable ag
Moving to Sustainable Ag.
  • Increase research on sustainable agriculture & improving human nutrition
  • Demonstrations of sustainable agricultural systems
  • Provide subsidies & increased foreign aid for sustainable practices
  • Training programs & creation of college curricula

What Can You Do?

Sustainable Agriculture

  • Waste les food
  • Reduce or eliminate meat consumption
  • Feed pets balanced grain foods instead of meat
  • Use organic farming to grow some of your food
  • Buy organic food
  • Compost your food wastes

Figure 14-30Page 303