Agriculture and the Environment: sustainable farming protects the soil, recycles nutrients, maintains diversity, and conserves water

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Agriculture and the Environment sustainable
farming protects the soil, recycles nutrients,
maintains diversity, and conserves water
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Rich soil from a temperate forest in Jordan
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Grassland Soils

• Temperate Biome
• Deep and dark
• Good for crops
• High organic content
• Hold water and nutrients

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Topsoil from Pennsylvania, USA
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Topsoil near Buenos Aires, Argentina
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Tropical Soils

• The soil is deep and bright red (iron oxides)
• The topsoil is very thin
• Nutrients are cycled rapidly
• Organic matter decomposes very quickly and
  transforms into inactive material that binds to
  clay
• Nutrients are leached from the soils
• Tropical soils are very fragile

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Tropical Soil from Ghana
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Soil terms

• Porosity Percentage of space that is empty, this
  affects the aeration and the oxygen content
• Permeability drainage, how fast water flows
• Water-holding capacity
• Workability How useful the soil is for farming.
• Fertility Nutrients in the soil

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Workability of clay, sand, silt and loam
texture nutrients Water flow Water holding Aeration workability
clay good poor good poor poor
silt medium medium medium medium medium
sand poor good poor good good
loam medium medium medium medium medium
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Inputs and Outputs
Outputs Food (quality?) Run off pollutes
water Habitat destruction Soil degradation Problem
s from GM modified plants?
Inputs Fossil fuels Mechanization Human
labor Fertilizer Pesticides Breeding
stock Seeds Irrigation
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Farming Input Fertilizer

• Fertilizers are used to increase crop yields
• Artificial chemical fertilizers nitrate,
  ammonia, phosphate..
• Natural fertilizers Increase organic matter in
  the soil by adding plant leaves and animal manures

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Farming Output Pollution from Chemical
Fertilizers Run off Nitrates and phosphates
from farm are washed into rivers and lakes Algal
Blooms in lakes and the rivers cause them to age
rapidly
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Toxic algal blooms in the ocean
Northeast Atlantic Ocean
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Farming Input Irrigation
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50 - 70 of the water used during irrigation is
wasted
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Drip Irrigation Method
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Output Salinization from Irrigation Northern
Australia
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Farming input Pesticides

• Over 98 of sprayed insecticides and 95 of
  herbicides reach a destination other than their
  target species, including nontarget species, air,
  water, bottom sediments, and food.

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Framing Input Fossil Fuels

• In the USA
• 31 for the manufacture of inorganic fertilizer
• 19 for the operation of field machinery
• 16 for transportation
• 13 for irrigation
• 08 for raising livestock (not including
  livestock feed)
• 05 for crop drying
• 05 for pesticide production
• From the Wilderness Publications
  http//www.fromthewilderness.com/free/ww3/100303_e
  ating_oil.html

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Farming Output Mechanization compacts the soil
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Farming Input Food distribution
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Farming Input Human Labor Intensive farming in
developing countries uses more human labor than
farming in developed countries.
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Farming Input Seeds The green revolution
started in 1944 in Mexico. Norman Borlaug
improved the drops by developing and introducing
a new hybrid of wheat that produced more food.
Irrigation, fertilizer, and machines were
introduced. He received a Nobel Prize in 1970.
His ideas spread to other developing
countries. Today seeds are selected for better
yields. Seeds are also genetically modified to
produce crops that are resistant to pests.
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Farming Input Breeding stock Selective
Breeding Selecting the best individuals to breed
in order to improve the stock
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Farming Input Genetically Engineered
organisms Introducing new genes to change the
organism
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Farming Animals Output Convert plants to meat
(protein)! Input 25 of animals feed to crops,
as much as 70 to cows in USA Rain forest cut for
grazing (Over grazing leads to soil depletion and
erosion)
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Monoculture versus Polyculture
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Polyculture many plants are farmed in an area.
Polycultures are less vulnerable to diseases
than monocultures
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Fragmentation of Land and Habitat
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Subsistence Farming Crops are grown to feed the
family Intense labor input The whole family
helps Sometimes marginally productive land is
used Polyculture is common many different
plants and a variety of animals Subsistence
Farming works well when the population density is
low.
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Unsustainable practice Ecological
Suicide Clearing land and leaving it bare -
erosion! Cutting trees for fire wood without
replanting Forcing multiple crops in a year
without allowing the soil to recover Slash and
burn agriculture Only sustainable if diverse
crops are used and the soil has time to
rest. Farming on Marginal Land (steep hillsides)
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Loss of produce during harvest and storage
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Farming marginal land
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Desperate farming
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Sustainable practices Recycle elements Organic
farming - add natural organic matter to the
soil Compost Lower fossil fuel consumption Avoid
overgrazing Crop rotation Polycultures Protect
forests Work to protect biodiversity Soil
Conservation measures
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Soil Conservation Measures

• Add lime to increase pH
• Add organic materials like compost
• Reduce the wind wind breaks, strip cultivation
  and shelter belts
• Terrace to avoid erosion
• Contour plowing
• Avoidance of plowing marginal lands

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Off contour swale to collect runoff
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Plants growing in swales reduce runoff
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Terracing
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Terracing
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Terracing
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Terracing
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Plants hold the soil in place
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Strip Farming protects the soil
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Minimum Tillage keeps organic matter covering the
soil.
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Fishing problems

• Overfishing
• Coral reef destruction
• Pollution
• Non-native species
• Habitat loss
• Toxic red tides
• Big concern Asia and Europe

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The transfer of energy is more efficient in
aquatic ecosystems, however humans tend to eat
higher on the food chain.