Food & Soil

Food & Soil Chapter 14 & 16

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

Perennial crops

Experimenting with ecology approach to agriculture

Polyculture- perennial grasses, legumes, sunflowers, grain crops, & plants that provide natural insecticides

Land Institute in Kansas

Croplands – grains Rangelands – meat Ocean fisheries

Food Providers

Wheat Rice Corn

Most important crops

High-input Uses large amounts of fossil fuel energy,

water, commercial fertilizers, pesticides

Monoculture

Industrialized agriculture

Form of industrialized Tropical developing countries Cash crops (bananas, coffee, soybeans,

sugar cane, cocoa, vegetables) Monoculture

Plantation Agriculture

Uses human labor or draft animals Produces enough crops or livestock for

family

Traditional Subsistence Ag

Increased input of human & draft labor, fertilizers, & water

Produces food for family & to sell for income

Traditional Intensive Ag

1. Develop & plant monocultures- selectively bred or genetically engineered key crops (rice, wheat, corn)

2. Produce high yields by high inputs of fertilizers, pesticides, water

3. Multiple cropping- increase number of crops grown per year on a plot of land

Green Revolution

1st Green Revolution- high input approach 1950 – 1970

2nd Green Revolution- since 1967, fast-growing dwarf varieties of rice & wheat

Saves large areas of forests, grasslands, wetlands, & easily eroded mountain terrain from being used to grow food

More Food, Less Land

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

Agricultural Industry

Practice of growing several crops on the same plot

Interplanting

http://www.endtimesreport.com/album.html

Plot contains several varieties of same crop

Polyvarietal Cultivation

2 or more different crops at the same time on a plot

Intercropping

Alley cropping Crops & trees are grown together

Agroforestry

Different plants maturing at various times are planted together

Polyculture

Of low-input polyculture1. Less need for fertilizer2. Less need for water3. Protection from erosion4. Less need for insecticides5. Less need for herbicides6. Insurance against profit loss

Advantages

Soil replenishment & crop growth1. Plant corn & trees at start of growing season2. Cut trees at start of 2nd growing season3. Add phosphate rock4. Plant leaves & stems (waste) of Mexican

sunflower – provides nutrients

Africa

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

Soil Erosion

Global – erodes 38% faster than topsoil is produced

US- 16% higher

Food Security Act 1985 Subsidy for taking erodible land out of

production Replant with grass or trees for 10-15 years

Farm Act

Wind erosion Crop failure Extensive drought

Started soil conservation practices

Dust Bowl

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

Desertification

Causes of desertification

ConsequencesCauses

Worsening drought

Famine

Economic losses

Lower living standards

Environmentalrefugees

Overgrazing

Deforestation

Erosion

Salinization

Soil compaction

Natural climate change

Figure 14-10Page 283

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

Irrigation Issues

Reduce irrigation

Switch to salt-tolerant crops(such as barley, cotton, sugar beet)

Prevention

Flushing soil(expensive andwastes water)

Not growing crops for 2-5 years

Installing underground drainagesystems (expensive)

Cleanup

Solutions

Soil SalinizationFigure 14-12

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

Reduces erosion

Saves fuel

Cuts costs

Holds more soil water

Reduces soil compaction

Allows several crops per season

Does not reduce crop yields

Reduces CO2 release from soil

Can increase herbicide use for some crops

Leaves stalks that can harbor crop pests and fungal diseases and increase pesticide use

Requires investment in expensive equipment

DisadvantagesAdvantages

Trade-OffsConservation Tillage

Terracing- cutting series of steps into a hillside◦ Retains water at each level = controls runoff

Reducing Soil Erosion

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

Contour plowing & strip cropping

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

Windbreaks (shelter-belt)- tall row of trees surround plot

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

Fertilizers

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Trade-OffsInorganic Commercial Fertilizers

Advantages Disadvantages

Do not add humus to soil

Reduce organic matter in soil

Reduce ability of soil to hold water

Lower oxygen content of soil

Require large amounts ofenergy to produce,transport, and apply

Release the greenhouse gas nitrous oxide (N2O)

Runoff can overfertilizenearby lakes and kill fish

Easy to transport

Easy to store

Easy to apply

Inexpensive to produce

Help feed one of every three people in theworld

Without commercialinorganic fertilizers,world food output coulddrop by 40%


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)

Organic Fertilizers

Spores of mushrooms- (puffballs & truffles) take in moisture & nutrients◦ One application lasts all year

Plant areas with nutrient-depleting crops then legumes the next year◦ Restores nutrients◦ Reduces erosion by keeping soil covered◦ Reduces crop losses to insects

Crop Rotation

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

Nutrition Problems

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

From Malnutrition

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

1. Immunize children2. Encourage breast feeding3. Prevent dehydration (from diarrhea)4. Prevent blindness in children (Vitamin A)5. Family planning services6. Increase education for women

Reducing Deaths

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)

Deficiencies

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

Overnutrition

Falling grain production Rise in meat consumption Large (potential) food supply deficit

China’s Food Problems

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ProjectedDisadvantages

Need less fertilizer

Need less water

More resistant to insects,plant disease, frost, anddrought

Faster growth

Can grow in slightly saltysoils

Less spoilage

Better flavor

Less use of conventionalpesticides

Tolerate higher levels ofpesticide use

Higher yields

ProjectedAdvantages

Trade-OffsGenetically Modified Food and Crops

Irreversible andunpredictable genetic and ecological effects

Harmful toxins in foodFrom possible plant cellMutations

New allergens in food

Lower nutrition

Increased evolution ofPesticide-resistantInsects and plant disease

Creation of herbicide-Resistant weeds

Harm beneficial insects

Lower genetic diversity

1. Requires huge amounts of fertilizer & water to increase yield

2. High cost3. Decreased yields due to soil erosion & loss of

fertility4. Irrigated soil becomes salty & waterlogged5. Underground & surface water becomes depleted

& polluted with pesticides & nitrates6. Population of rapidly breeding pests develop

genetic immunity to pesticides

Limits to Increased Food Production

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

Types of New Food

http://factoidz.com/winged-bean-nutrition-and-health-benefits/

Convincing farmers to take financial risk

Convincing consumers to try new foods

Problems with New Foods

40% of food production

AND 2/3 of rice & wheat

Come from 20% of irrigated croplans

Food Production Good news-

irrigated area has grown 3x

Bad news- population is growing faster

Tropical forests & arid land = poor soil fertility, steep slopes

Unlikely to be sustainable if cultivated

Increasing Irrigated Land

Irrigation would require expensive dams Large inputs of fossil fuels to move water Groundwater depletion Expensive to stop:

◦ Erosion◦ Groundwater depletion◦ Salinization◦ Waterlogging

Problems

Grow more food in urban areas like:◦ Empty lots◦ Backyards◦ Rooftops◦ Balconies

Urban Areas

70% of food is wasted ◦ Spoilage◦ Inefficient processing & preparation◦ Plate waste

Food Wastes

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

Meat Production

Animal waste may contaminate groundwater or nearby streams

Smell Increased demand for feed (grain)

Environmental Effects

Too many animals graze too long & exceed the carrying capacity of grassland area

1. Lowers net primary productivity2. Reduces grass cover3. Prolonged drought may lead to desertification

Overgrazing

1. Move to another grazing area2. Fence off riparian areas3. Provide supplemental feed at selected sites

Sustainable Rangeland Management

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

Fish

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)

Fishing Methods

Spotter airplane

Fish farmingin cage

Trawlerfishing

Purse-seinefishing

sonartrawl flaptrawllines

trawl bag

Long line fishing

lines withhooks

Drift-net fishing

fish caughtby gills

float buoy

Figure 14-24

fish school

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

Issues

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

Other Methods

Figure 14-27

Highly efficient

High yield in smallvolume of water

Increased yieldsthrough cross-breeding and genetic engineering

Can reduce over-harvesting of conventional fisheries

Little use of fuel

Profit not tied to price of oil

High profits

AdvantagesLarge inputs of land, feed, And water needed

Produces large and concentrated outputs of waste

Destroys mangrove forests

Increased grain productionneeded to feed some species

Fish can be killed by pesticide runoff from nearby cropland

Dense populations vulnerable to disease

Tanks too contaminated touse after about 5 years

Disadvantages

Trade-OffsAquaculture

Figure 14-28

• 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

Solutions

More Sustainable Aquaculture

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

Figure 14-29

High-yield polyculture

Organic fertilizers

Biological pest control

Integrated pestmanagement

Irrigation efficiency

Perennial crops

Crop rotation

Use of more water-efficient crops

Soil conservation

Subsidies for more sustainable farming and fishing

IncreaseSoil erosion

Soil salinization

Aquifer depletion

Overgrazing

Overfishing

Loss of biodiversity

Loss of primecropland

Food waste

Subsidies for unsustainable farming and fishing

Population growth

Poverty

Decrease

SolutionsSustainable Agriculture

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


• 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

What Can You Do?

Sustainable Agriculture

Food & Soil

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