1. The sector of the economy that seems likely to unravel first is food.
Eroding soils, deteriorating rangelands, collapsing fisheries, falling water tables,
and rising temperatures are converging to make it difficult
to expand food production fast enough to keep up with the demand.
LESTER R. BROWN

2. Soil Why is soil so important? It’s simple food.
Feeding a growing human population:
Many of the poor suffer health problems from chronic lack of food and poor nutrition, while many people in developed countries have health problems from eating too much food.
A proper diet requires 2500 calories a day for males and 2000 calories for females. It also requires a balanced intake of proteins (30%), carbohydrates(60%) and fats(10%). People are considered undernourished with fewer than 2000 calories per day.
______________means that every person gets enough nutritious food to live an active and healthy life.
Food insecurity (1 in 6 people) living with chronic hunger and poor nutrition. ____________________
____________________________.

3. Hunger and Malnutrition
Although there is enough food produced in the world many people go hungry. ____________
__________________________________________________________________________________________________________________________.
The greatest obstacles to providing enough food for everyone are
__________________________________________.
Political upheaval , corruption, war which interfere with _____________________________________.
Stored food _______________________________.
The harmful ________________________________
_____________________________________________.
In terms of famine and malnutrition, about 11 million children die from starvation each year and 850 million people are considered malnourished (lack of protein in the diet). Chronic undernourishment results in mental retardation, stunted growth, susceptibility to disease, lower life expectancy and weakness.
Over nutrition: 1 billion people have health problems because of this. Lowers life expectancy, greater susceptibility to disease and illness and lower life quality.

4. Food Production Food production ____________________
___________________________________________________________________.
_____________________________. (Grains are small, hard, dry seeds. Corn is considered a grain when harvested late) They supply 77% of the world’s food and use 11% of the land.
____________________________________________which supply 16% of the world’s food and use 26% of the land. About 69% of the grain grown in the United States is used to feed animals.
______________________________supply about 7% of the world’s food.

5. Feeding a Growing Population
People must consume 2,200 calories of food per day to live an active healthy life
Area of food production unevenly distributed among population. ________________________
___________________________________________________________________________________________________________________________________________________________.
Of the 14 _________________ supply about 50% the human caloric intake. They also supply the world with 42% of their protein. __________________
___________________________________________________________________________.
Golden rice was genetically engineered to contain _______
__________________________________________________
Using corn as _______is driving up the price leading to more hunger.

6. Agriculture
The number of people the world can support depends mostly on their per capita ___________
____________________________________________________________________________.
Research has shown that those living very low on the food chain or very high on the food chain do not live as long as those that live somewhere in between.

7. Growing Crops
There are two basic was that crop agriculture is accomplished:
1. ___________________________________________________________________.
2. ___________________________________________________________________.
Industrialized agriculture (_____________________________) uses:
1. Heavy equipment that burn ________________________
2. Large _____________________(become corporate- Monsanto)
3. Large _____________________
4. Large _____________________(monocultures deplete soil nutrients)
5. Large _____________________
Why grow crops this way? To produce high yield monocultures. Yield-The amount of food produced per unit of land.
___________________: is industrialized agriculture used in tropical developing countries to grow cash crops. (bananas, coffee, soybeans, sugar cane and palm oil). It brings money to countries that need it but leads to :
1. Slash and burn techniques
2. loss of biodiversity as rainforests are destroyed
3. Larger inputs of inorganic fertilizers due to very low nutrients in rainforest soil
4. Soils are depleted quickly and more forest is needed every 4 years to continue

8. Traditional Subsistence Agriculture
Traditional agriculture (low input) is practiced by 2.7 billion people in _______________________.
It involves mainly _________________________ to grow enough food for the family with a little left over to sell or store.
In contrast to high input monocultures grown in industrialized agriculture, traditional agriculture is based on __________: growing many different crops on the same plot of land. Benefits of polyculture involve:
_____________________________________
_________________________________________________________________________.
Slash and burn agriculture is also used to clear land for polyculture agriculture. After the soil is depleted of nutrients it takes ____________________________________________.

9. The Birth of Industrialized Crop Production: The Green Revolution
The Green Revolution (High impact Agriculture)
Green revolution is a popular term for the technologically advanced agricultural practices that increased crop yield after WWII. It involved three steps:
1. The introduction of ___________________________________________________
_____________________________________________________________________.
2. Large use of ________________________________________________________.
3. _________________is growing more than one kind of crop in the same area. Most common form is one crop is started after the growing season for the previous crop has ended.
Since 1950, high-input agriculture has produced more crops per unit of land.
In 1967, fast growing dwarf varieties of rice and wheat were developed for tropics and subtropics.
Lack of water, high costs for small farmers, and physical limits to increasing crop yields hinder expansion of the green revolution.

10. Since 1978 the amount of irrigated land per person has declined due to:
Depletion of underground water supplies.
Inefficient irrigation methods.
Salt build-up and cost of irrigating crops.

11. Genetically Modified Food
Artificial selection has been used for centuries to develop _____________________________
_________________________________. It is a slow process but, crosses with older strains can ______________________________________.
Genetic Engineering (faster): isolation of a gene from one source (plant, bacteria) for a desired trait (insect resistance), make copies of genes, then place those genes in another plant, producing a ______________________.
EXAMPLE: Tomatoes
Ethylene production (gas produced which makes them ripen quickly) grocers spray fruit with ethylene to start ripening process
STRATEGY: isolate gene responsible for ethylene
GE tomato (Endless Summer) does not ripen until it gets to the store: longer shelf-life

12. Trade-Offs Genetically Modified Crops and Foods Projected Advantages
Projected Disadvantages
_________________
Irreversible and unpredictable genetic and ecological effects
________________
More resistant to insects, disease, frost, and drought
Harmful toxins in food from possible plant cell mutations
Grow faster
____________________
__________________
Can grow in slightly salty soils
Increased development of pesticide-resistant insects and plant diseases
Less spoilage
Better flavor
Can create herbicide-resistant weeds
__________________
Tolerate higher levels of herbicides
Can harm beneficial insects
_______________
_______________________

13. Producing More Meat
About half of the world’s meat is produced by ________________________________________
_____________________________________________________________________________.
The other half is produced under __________________________________________________
Takes about 16 pounds of grain to produce 1 pound of edible meat. 20% of the world’s richest countries eat 80% of the meat.
Eat the grain directly would see a 20 fold increase in the calories available.
Eating more chicken and farm-raised fish and less beef and pork reduces harmful environmental impacts of meat production and _______________________________________
_________________ Eating lower on the food chain (plant products) frees up even more food resources.

14. Trade-Offs
Animal Feedlots
Advantages
Disadvantages
_____________________
Need large inputs of grain, fish meal, water, and fossil fuels
Higher profits
Concentrate animal wastes that can pollute water
Less land use
______________________
Reduced soil erosion
_________________________________________________________________________________________________.
Help protect
biodiversity

15. Aquaculture Trade-Offs Aquaculture Advantages Disadvantages
Raising large numbers of fish and shellfish in ponds and cages is world’s fastest growing type of food production. Fish farming involves cultivating fish in a controlled environment and harvesting them in captivity.
High efficiency
Needs large inputs of land, feed, and water
High yield in small volume of water
Large waste output destroy quality of water
Destroys mangrove forests and estuaries
______________________________________________________________________
Uses grain to feed some species
Low fuel use
____________________________________________________________________________
High profits
_______________________________________
Tanks too contaminated to use after about 5 years
Labeled in the stores as farmed raised verses wild caught.

16. Solutions More Sustainable Aquaculture
• _____________________________________________________________________
• Improve management of aquaculture wastes
• Reduce escape of aquaculture species into the wild they can ____________________
___________________________________
• Restrict location of fish farms to reduce loss of mangrove forests and estuaries
• Farm some aquaculture species in deeply submerged cages to protect them from wave action and predators and allow dilution of wastes into the ocean
• Certify sustainable forms of aquaculture

17. Food Production: Environmental Impacts
___________________________________________________________________________________________________________________________________________________________.
Loss of a variety of genetically different crop and livestock strains might limit raw material needed for future green and gene revolutions. In the U.S., 97% of the food plant varieties available in the 1940 no longer exist in large quantities.
Industrialized agriculture uses about 17% of all commercial energy in the U.S. and food travels an average 2,400 kilometers from farm to plate.

18. Food Production NATURAL CAPITAL DEGRADATION Biodiversity Loss Soil
Water
Air Pollution
Human Health
Loss and degradation of grasslands, forests, and wetlands
Erosion
Water waste
Greenhouse gas emissions (CO2) from fossil fuel use
Nitrates in drinking water (blue baby)
Aquifer depletion
Loss of fertility
Increased runoff, sediment pollution, and flooding from cleared land
Greenhouse gas emissions (N2O) from use of inorganic fertilizers
Pesticide residues in drinking water, food, and air
Salinization
Fish kills from pesticide runoff
Waterlogging
Killing wild predators
to protect livestock
Desertification
Pollution from pesticides and fertilizers
Greenhouse gas emissions of methane (CH4) by cattle (mostly belching)
Contamination of drinking and swimming water from livestock wastes
Loss of genetic diversity of wild crop strains replaced by monoculture strains
Algal blooms and fish kills in lakes and rivers caused by runoff of fertilizers and agricultural wastes
Other air pollutants
from fossil fuel use
and pesticide
sprays
Bacterial contamination of meat

19. Soil Degradation: Erosion
Erosion is the movement of soil components, especially surface litter and topsoil, from one place to another and is a serious issue facing modern farming. __________________. Erosion _____________________________________________________________________________.
6.4 billion tons of soils are eroded from the U.S. each year; this would fill 320 million average-sized dump trucks that, if parked end-to-end, would extend to the moon and ¾ of the way back!
Erosion is caused by _________________
_____________________________________________________________________________________________________.
Wind erosion:
1. Saltation: one particle hitting another and being blown across the surface of the soil.
2. Suspension(_____): airborne soil. Soil can travel hundreds of miles in the right conditions.
3. Surface Creep: mountains/sand dunes; surface creeping slowly across. Landslides are an example of a very fast surface creep.
4. Aeolian soils are sand sized particles transported by wind.

20. Water Erosion
1. Mass slippage: (like in California) where it is very wet and large amounts of soil slip away in large chunks (mud slides). Leaves behind a hillside scar.
2. Splash erosion: raindrops hit soil & remove it
3. Sheet erosion: _____________________________
________________________________________________________________________________________________________________________________.
4. Gully erosion: water converges into small streams and takes with it large amounts of soil
5. Rill: concentrated flow across the surface of soil. Leaves rivets (micro channels).

21. Human Impact on Erosion
______________________________________________________________________________________________destroy plant cover and leave soil vulnerable to erosion. This destroys in a few decades what nature took hundreds to thousands of years to produce.

22. Soil is eroding faster than it is forming on more than one-third of the world’s cropland.

23. Desertification: Degrading Dry lands
Desertification is a type of land degradation in which a relatively dry land region becomes increasingly arid (__________________________), typically losing its bodies of water as well as vegetation and wildlife. It is caused by a variety of factors, such as climate change and human activities. ___________________________________________________.

24. About one-third of the world’s land has lost some of its productivity because of drought and human activities that reduce or degrade topsoil.

25. Repeated Irrigation has Consequences
Excessive salts in soil may decrease productivity by:
1. _________________________________________________.
2. _________________________________________________.
3. _________________________________________________.
4. _________________________________________________.

26. Solutions Soil Salinization Prevention Cleanup
Reduce irrigation or use _____________ to use less water and lower influx of salt.
Flush soil (expensive and wastes water)
Stop growing crops for _________until the salt has been flushed away
Irrigate with water that has a low salt content
Switch to salt-tolerant crops (such as barley, cotton, sugarbeet)
Install underground drainage systems that will prevent water from pooling and evaporating (expensive)

27. Further Impacts of Agriculture
Habitat destruction to build farms and feedlots reduce biodiversity. ___________________
______________________________________________________________________________
__________________________________________.
2. Water pollution: __________________________
_____________________________________________________________________________________________________________________________.
3________________: Monocultures deplete soil of vital nutrients and must be replaced artificially
Plants need : Macronutrients (Nitrogen, Phosphorus and Potassium) and micronutrients in small amounts (Selenium, Zinc and Iron). Excessive amounts of zinc, copper and nitrogen can be toxic to plants.
Fertilizers can help restore soil nutrients in turn restoring soil fertility.
A. Organic fertilizers: from plant and animal (fresh manure, or compost) materials.
B. Commercial inorganic fertilizers: Active ingredients contain nitrogen, phosphorous, and potassium and other trace nutrients
Benefits – compositions are known; they are soluble and immediately available to the plant
Costs – quickly leach away; this pollutes the water; doesn’t help the water holding capacity of the soil like organic fertilizers do.

28. Reducing Soil Degradation
___________________________________.
In undisturbed ecosystems, the roots of plants help anchor the soil, and usually soil is not lost faster then it forms.
_____________________________________________________________________________.
Sustainable agriculture through planting and irrigation techniques can reduce soil degradation and increase soil conservation by protecting soil from wind and water
Producing food more sustainably through soil and water conservation:
1. _____________________________: can reduce wind erosion. Long rows of trees are planted to partially block the wind. They can also help retain soil moisture, supply some wood for fuel, and provide habitats for birds.

29. 2. _______: converting steeply sloped land into a series of broad nearly level terraces.
3. ________________: On ground with a significant slope grow crops that are in rows across the slope so one row can act as a dam to the previous.
4. _______________: involves planting rows of crops with alternating strips of a cover crop that completely covers the soil. (corn or cotton with legumes, rye or alfalfa)
5. _________________________: trees planted in strips; crops grown between trees
6. ____________: Eliminate the use of machines to till or turn over the soil.

30. (efficiency 60% and 80% with surge valves)
7. Irrigation techniques: Brings water to agricultural crops uses about
60% of the world’s freshwater supplies
Center pivot
(efficiency 80% with low-pressure sprinkler and 90–95% with LEPA sprinkler)
Drip irrigation
(efficiency 90–95%)
Gravity flow
(efficiency 60% and 80% with surge valves)
Above- or below-ground pipes or tubes deliver water to individual plant roots. _________________
___________________________.
Water usually pumped from underground and sprayed from mobile boom with sprinklers. Requires machinery.
Water usually comes from an aqueduct system or a nearby river. Cheap and easy.
Gravity flow was invented to _______________________________. When basin flood crops get watered. The ________________________________________________________. This is why flood valleys have always been good for agriculture and many societies where established near them. (Mesopotamia an area geographically located between the Tigris and Euphrates rivers)

31. Soil
Soil is a renewable resource as it is slowly renewed (erosion) resource that provides most of the nutrients needed for plant growth and also helps purify water.
Soil formation begins when bedrock is broken down by physical, chemical and biological processes called ________________________.
To form 2.5 cm (1 in.) it may take from years.
Physical Weathering (wind, water, ice)
Chemical and biological weathering: A plant’s roots or animal cells undergo cell respiration and the CO2 produced diffuses into soil, reacts with H2O & forms carbonic acid (H2CO3). This eats parts of the rock away.
______________________________(like making it new) by breaking down dead organisms and returning some of their nutrients to the soil. But, in the tropical rainforests, all of the nutrients are caught in the trees and when cut down & burned the soil cannot get the nutrients back.

32. Soil Ecology Soil: A thin layer on top of Earth’s crust.
A natural resource that affects ecosystems
_____________________________________________________________________________________________________________________________________________________________________________________________________________________
Soil is affected by agents such as weather, wind, water and organisms.
Composition of typical soil:

33. Importance of Soil
1. Organisms, mainly microorganisms, inhabit the soil & depend on it for shelter, food & water.
2. Plants anchor themselves into the soil, and get their nutrients and water. Terrestrial plants could not survive without soil, therefore, humans could not exist without soil either.
Mature soils, or soils that have developed over a long time are arranged in a series of horizontal layers called soil horizons

34. Soil Horizons O HORIZON (surface litter or organic layer)
A HORIZON (topsoil)
B HORIZON (subsoil)
C HORIZON (weathered parent material)
R HORIZON (bedrock-parent material)
Soil Horizons
-leaves & partially decomposed organic debris
-__________________________________________
__________________________________________
Plant roots
-Organic matter decomposed plants and animals (humus), living organisms, inorganic minerals
-Has a granular texture and begins to lose nutrients due to plants using them and to deeper layers by leaching referred to as eluviation.
-_________________________________________
Leeched out
-light-yellowish in color because it accumulates iron, clay, aluminum and organic compounds, a process referred to as illuviation.
-Can have nutrients in areas where rainwater leeched nutrients from topsoil but has very little humus.
Deposited in
-Partially broken-down inorganic materials like rocks (broken bedrock).
-Most roots do not go down this deep

35. Layers in Mature Soils
_____________: the downward movement of water through soil.
Leaching: dissolving of minerals and organic matter in upper layers carrying them to lower layers. _____
___________________________________________________________________________________________________________________________________________________________________________.
The soil type determines the degree of infiltration and leaching.
_______________________(zone of leaching)
-Dissolved and suspended materials move downward
“E”, being short for eluviated, is most commonly used to label a horizon that has been significantly leached of its mineral and/or organic content, leaving a pale layer largely composed of silicates
These are present only in older, well-developed soils, and generally occur __________________________.

36. Mosaic of closely packed pebbles, boulders
Weak humus-mineral mixture
Alkaline,
dark,
and rich
in humus
Dry, brown to reddish-brown with variable accumulations of clay, calcium and carbonate, and soluble salts
Clay, calcium compounds
Desert Soil
(hot, dry climate)
Grassland Soil
(semiarid climate)

37. ________________________________________________________________________________________________________
________________________________________________________________________________________________
Forest litter leaf mold
Acidic
light-colored humus
Humus-mineral mixture
Light, grayish-brown, silt loam
Iron and aluminum compounds mixed with clay
Dark brown firm clay
Tropical Rain Forest Soil
(humid, tropical climate)
Deciduous Forest Soil
(humid, mild climate)

38. __________________________________________________
Acid litter and humus
Light-colored and acidic due to decomposition of needles.
Humus and iron and aluminum compounds
Coniferous Forest Soil
(humid, cold climate)

39. Soil Components COMPONENT DESCRIPTION Clay •very fine particles
•compacts easily
•low permeability to water
•upper layers become waterlogged
Gravel
•coarse particles
•rock fragments
Loam
_____________________
•equal mixture of clay, sand, silt, and humus
•rich in nutrients
•holds water but doesn’t become waterlogged
Sand
•coarser than silt
•good for crops/plants requiring low amount of
water (water flows quickly)
Silt
•very fine particles (b/w size of sand & clay)
•easily transported by water

40. Soil Properties Particle Size
Texture: The percentages (by weight) of different sized particles of sand, silt and clay that it contains give soil different textures.
To tell the difference in soil, take the soil, moisten it, and rub it between your fingers and thumb.
Gritty -has a lot of sand
Sticky- high clay content and you should be able to roll it into a clump
Silt- smooth
Particle Size
>2mm in diameter = gravel/stones (not actually considered soil because it doesn’t have direct value to plants.
0.05 to 2mm = sand (the largest soil particles) can be seen easily with the eye.
0.002 to 0.05mm = silt – about the size of flour and barely visible with the eye.
<.002mm = clay (has the greatest surface value) – only seen under and electronic microscope.

41. Soil Properties Continued
Soils vary in the size of the particles they contain, the amount of space between these particles, and how rapidly water flows through them. This determines a soils ability to hold water.
Permeability: The rate at which water and air moves from upper to lower soil layers. _____________________________________________________________________.
Porosity: A measure of the volume of soil and the average distances between the spaces. This affects the soil’s ability to absorb and hold water. ________________
_____________________________________________________________________.
Aeration: The ability of oxygen to infiltrate the soil. ____________________________
_____________________________________________________________________.

42. Soil Chemical Properties
The pH of most soils ranges from 4.0 to 8.0 most plants grow best in neutral soil. As soil pH decrease porosity, aeration and nutrient holding capacity drop with it.
But, the soil of the Pygmy Forest in California is extremely acidic ( ) and in Death Valley, California, it is very basic (10.5).
Plants are affected by pH because of the solubility of nutrient minerals. Soils with higher pH are more capable of absorbing cations (K+) preventing them from leaching out of the soil.
Nitrogen (N): plant fertilizer component needed for growth and survival
Phosphorus (P): plant fertilizer component needed for growth and survival
Potash (K): common name for mined and manufactured salt compounds that contains potassium oxides The name derives from "pot ash", which refers to plant ashes soaked in water in a pot, can be used as fertilizer.

43. Growing and Using food Sources More Efficiently
People in urban areas could save money by ________________________________________.
Urban gardens provide about 15% of the world’s food supply.
One third of the food produced worldwide is wasted, costing the global economy around $US750 billion a year, a new report by the UN food agency says.
In the United States we waste up to 40% of our food at a cost of 1 billion dollars a year just to dispose of the trash.
______________________________________________________________________________________________________________________________________________________________________________________________________________________________________.

44. More Sustainable Agriculture: Organic Farming

45. Reducing the Amount of Land Needed for Agriculture
Increase crop yield by:
A. ____________________________________________________________________
_____________________________________________________________________.
B. ___________________________________________________________________.
C. ___________________________________________________________________
D. ___________________________________________________________________.
2. Decreasing the demand for agricultural land by:
A. ____________________________________________________________________
_____________________________________________________________________.
B. ___________________________________________________________________.
C. ___________________________________________________________________.
D. ___________________________________________________________________.

46. Case Studies and Legislation
The Dust Bowl, of the 1930’s in Oklahoma, Texas, Kansas, was a period of severe dust storms that greatly damaged the ecology and agriculture of the US and Canadian prairies severe drought, plowing and uncovered land caused the phenomenon. During the drought of the 1930s, the unanchored soil turned to dust, which the prevailing winds blew away in huge clouds that sometimes blackened the sky. These choking billows of dust – named "black blizzards" or "black rollers" – traveled cross country, reaching as far as such East Coast cities as New York City and Washington, D.C.
The Dust Bowl led to the Soil Conservation(Erosion) Act of 1935 in an attempt to address farm erosion problems by bringing within its policy and purposes, the improvements and preservation of national soil resources.
Soil erodes faster than it forms on most U.S. cropland, but since 1985, has been cut by about 40%.
1985 Food Security Act (Farm Act): farmers receive a subsidy for taking highly erodible land out of production and replanting it with soil saving plants for years.