Enviroment Notes

8/8/2019 Enviroment Notes

1/29


2/29

Table 1.1Science As a Way of Knowing

Scientists collaborate Many people often work on different aspects of a problem. Creativity, insight, aesthetics and even luck play roles in

scientific research.Scientific Design

Reproducibility Experiments must be designed and recorded so they can be

reproduced exactly by other researchers. Controlled Studies

Comparisons are made between experimental and control

populations.- Every variable except the one being studied is held

constant.Scientific Design

Blind Experiment Conducted so investigators do not know which is the control

and which is the experimental group, until after data havebeen gathered and analyzed.

Double-Blind Neither the subject nor the investigators know which

participants are receiving an experimental treatment.Reasoning

Deductive Reasoned conclusion Starting with a general principle and deriving a testable predication

about a specific case. Premise: All dogs have four legs. Premise: Rover is a dog, Conclusion: Rover has four legs.

Reasoning Inductive

Specific examples are examined to locate patterns and derive generalexplanations from collected observations.

Reasoning from particular instances to a general conclusion


3/29

if all the people you've ever met from a particular town have been very strange, you might then say "all theresidents of this town are strange"

Hypotheses and Theories Hypothesis

Conditional explanation that can be tested by further

observation or experiment.- Logically, an hypothesis is based on inductive reasoning,

can be shown to be wrong, but can almost never be shownto be unquestionably true.Evidence is always provisional.

Scientific TheoryScientific Method

Modeling and Natural Experiments

In some areas, historic evidence can be examined for supportor contradiction of an idea.

Another method of investigation is using a model simulating thephenomenon under study. Models represents researchers assumptions about how a

system works.- Can produce contradictory results.

Statistics and Probability

Probability An attempt to measure and predict the likelihood of an event.

Sample Size A critical experimental variable is the number of observations

necessary in order to have a reliable representation of apopulation.

Paradigms and Scientific Consensus Paradigms

Overarching model of the world that guides ourinterpretations of events.

- Tend to guide the types of questions asked byinvestigators.

Paradigm shifts occur when a majority of scientists agree theolder general explanations no longer fit the observations.

Approaches to Knowledge and Thinking


4/29

Analytical Thinking How can I break this problem into parts ?

Creative Thinking How can I approach this differently ?

Logical Thinking How can deductive reasoning help ?

Critical Thinking What am I trying to do ?

Reflective Thinking What does it all mean ?

Steps in Critical Thinking Identify and evaluate premises and conclusions in an argument.

Acknowledge and clarify uncertainties, vagueness,equivocation, and contradictions.

Distinguish between facts and values. Recognize and assess assumptions. Distinguish source reliability or unreliability. Recognize and understand conceptual frameworks.

History of Conservation and Environmentalism Four Distinct Stages:

Pragmatic Resource Conservation Moral and Aesthetic Nature Preservation Modern Environmentalism Global Environmental Citizenship

Pragmatic Resource Conservation President Theodore Roosevelt and his chief conservation

advisor, Gifford Pinchot, believed in utilitarian conservation. Forests should be saved so they can be used to provide

homes and jobs.- Should be used for the greatest good for the greatest

number, for the longest time.Moral and Aesthetic Nature Preservation

John Muir, first president of the Sierra Club, opposed Pinchotsutilitarian policies. Biocentric Preservation


5/29

- Emphasizes the fundamental right of all organisms topursue their own interests.

Modern Environmentalism Rachel Carson, Silent Spring.

Awakened the public to threats of pollution and toxicchemicals to humans as well as other species.

- Modern environmentalism extends concerns to includeboth natural resources and environmental pollution.

Global Concerns Increased travel and communication enables people to know

about daily events in places unknown in previous generations. Common environment shared on a global scale.

- Global EnvironmentalismCURRENT ENVIRONMENTAL CONDITIONS

Causes of Environmental Degradation More than 6 billion people now occupy the earth, and we add

about 85 million more each year.- Most growth will be in poorer countries where present

populations already strain resources and services.Human Dimensions of Environmental Science

A small fraction of the worlds population live in increasingluxury, while a more than 1.3 billion people live in acute poverty. Seventy percent are women and children. Often meet short-term survival needs at the cost of long-term

sustainability. Cycle of poverty, illness and limited opportunities become

cyclic.Fig. 1.15

Rich and Poor Countries About 20% of the worlds population lives in the twenty richest

countries. Average per capita income above $25,000.

Other 80% live in middle or low-income countries. Ten poorest countries each have average per capita income

of less than $200.00.


6/29

Richest 200 people in the world have have a combined wealthof $1 trillion. More than total owned by poorest half of the world population

(3 billion).

Table 1.4

Sustainability Sustainable Development

Meeting the needs of the present without compromising theability of future generations to meet their own needs.

Indigenous Peoples Indigenous peoples are generally among the least powerful,

most neglected groups. In many countries, traditional caste systems, discriminatory

laws, economics, or prejudices repress indigenous peoples. In many places, indigenous people in traditional homelands

guard undisturbed habitats and rare species.- Recognizing native land rights may safeguard ecological

processes.

Summary: Environmental Science Science As a Way of Knowing

Scientific Design Reasoning Scientific Theory

Approaches to Thinking History of Environmentalism Human Dimensions

Rich and Poor Countries

Energy, Matter and LifeChapter 2

Matter


7/29

Matter Conservation of Matter

Atoms Sub-atomic particles

Atomic number Atomic mass

Ions

Chemical Bonding Covalent

Ionic

Molecule

Compound

Compounds Inorganic

CO2, O2, N2, H2O

Organic

Chemical Reactions Oxidation Reduction

Hydration

Reaction with Acid or base

pHEnergy

Potential

Kinetic Heat

Specific Heat amount of heat to warm 1 kg 1oC.

Energy Transfers =Thermodynamics First Law of Thermodynamics = energy is conserved, neither created

or destroyed, transferred or transformed Second Law of Thermodynamics = with each successive energy

transfer or transformation in a system, less energy is available to do

work

Life Cell


8/29

Nucleus

Cytoplasm

Organelles Metabolism- enzymatic reactions

Cell Wall

Water of Life 60 to 70 of organisms by weight

Salt and other compounds dissolve easily Electrolytes

Water molecules are cohesive Capillary action Surface tension

Exists as liquid over a wide temperature range

Expands when crystallizes = solid

Has high specific heat absorbs or loses a great deal of energy as it changestemperature.

Energy of Life The Sun

Electromagnetic Spectrum

Metabolism Chemistry Photosynthesis - captures

6 H2O + 6 CO2+ solar energyC6H12O6+ 6 O2

Cellular respiration releasesC6H12O6+ 6 O26 H2O + 6 CO2+energy released

Biogeochemical Cycles Hydrologic cycle = Water Cycle

Carbon Cycle Nitrogen Cycle

Nitrogen-fixing bacteria

Nitrites NO2-1

Nitrates NO3-1

Ammonia NH3 Ammonium NH4

+1

Denitrifying bacteria

Mineral cycles Phosphorus


9/29

Sulfur

Ecosystem Ecological System

Biological Community

Populations

Species

Energy of an ecosystem Open system exchange of energy, matter across boundaries

Closed system

Trophic Level Primary producers

Consumers

Herbivores Carnivores

Omnivores

Detritivores

Decomposers

Food Chain

Food Web

Energy exchange in Ecosystems

Ecological pyramidsEnergy pyramid related to biomass period

Populations, Communities and Species InteractionChapter 3

Principle of Limiting Factors Tolerance limits

Minimum limits

Maximum limits Limiting factors in Mineral cycles

Phosphorus

Sulfur

Evolution Natural Selection


10/29

Selection pressure Physiological stress

Predation Competition

Luck

Adaptation

Speciation

Modes of Evolution Divergent evolution

Convergent evolution

Speciation Geographic isolation

Reproductive isolation - divergence

Naming of things Kingdom

Phylum

Class

Order

Family

Genus

Species

Ecological Niche A species way of life or functional role in the ecosystem = occupation

Range of tolerance

Types of resources used

How it interacts in the ecosystem

How it affects the flow of energy

Habitat = location where a species lives

Generalist species = Eurytopic species Specialist species = Stenotopic species

Resource Partitioning

Species interactions


11/29

Interspecific competition = competition among species overlap of

fundamental niches

Predator Prey Relationship

Native Species Non-native species

Exotic species Alien species

Killer bees

Zebra mussels

Kudzo

Indicator species

Early warning that ecosystem is being damaged Keystone species

Role of species is important for ecosystem health. Sea otters

Symbiosis Sym = together

Bios = life

An intimate and mutually advantageous partnership of dissimilar

organisms.

MutualismCommensalism

Benefits one species

Neither harms or helps the other species Epiphyte plants Air plants

Defensive Mechanisms Batesian mimicry look like a dangerous predator

Mullerian mimicry two dangerous organisms look alike so bothbenefit

Exponential Growth

Carrying Capacity (K) The number of individuals of a given species that can be sustained indefinitely

in a given space (area or volume)


12/29

Often in populations it is the number of organisms that the environment will sustain.

When will a population of 5 million organisms reach its carrying capacity if the

population doubles every 10 years, the environmental increase of food

production is 1 million individuals able to be feed per year, and the initial

environment can sustain a population of 10 million?

Logistic Growth

Fig. 3.18

Logistic growth

Fig. 3.19

Population density controls Density-independent population controls

Floods, hurricanes, severe drought Not dependent on the density of the population

Density-dependent population controls Competition for resources, predation, parasitism or disease. Density plays a part in how these affect the population

Potential epidemics, Bubonic plague

Environmental resistance

Reproductive Strategies

Table 3.2

Primary Productivity The rate of biomass production or the conversion of solar energy into

chemical energy stored in living (or once-living) organisms.

Net primary productivity = after respiration

Fig. 3.21

Fig. 3.22

Boundaries of communities


13/29

Ecotones boundary between adjacent communities

Edge effect environmental and biotic conditions on the edges

Fig. 3.26

Fig. 3.23Primary Succession

Secondary Succession

Fig. 3.28

Climax community End of succession?

Old age forests?

Stable climax

Environmental Science

Test 1 Review Sheet

This Review sheet is produced as a study aid. This sheet may or may not be all inclusive of thematerial you are held responsible for the test. If the material was covered in class and/or it is in

your textbook you should know it.Chapter 1

Terms to know:

Environment, Environmental Science, science, hypothesis, theory, controlled study, deductivereasoning, inductive reasoning, blind experiment, significant numbers, reproducibility, model,

probability, paradigm, analytical thinking, creative thinking, critical thinking, reflective thinking,

environmentalism, utilitarian conservation, biocentric preservation, modern environmentalism,global environmentalism, environmental degradation, sustainability, resources, indigenous

people

Concepts and questions to know:

1. What is the problems with rich and poor countries as they deal with environmental

science.

2. Why do we need to live sustainable as well as have sustainable development?3. Who are these people of Environmental Science? Rachel Carson, John Muir, Gifford

Pinchot, Pierre Poivre, Theodore Roosevelt, David Brower, Barry Commoner, and

Marshall McLuhan.


14/29

4. What are the steps in critical thinking?

5. How can you detect the Baloney of science?

6. What advantages does modeling have for environmental science?7. Within a scientific investigation a scientist will follow what series of logical steps to

investigate a problem?

8. Compare and contrast deductive reasoning from inductive reasoning.9. Why is it important that scientific studies be reproducible?

10. Compare and contrast controlled studies to blind experiments to double-blind design.

11. What is the interaction of the various disciplines that are involved in environmentalscience?

12. What is environmental science?

Chapter 2

Terms to know:

Ecology, matter, energy, kinetic energy, potential energy, heat, thermodynamics, atom, atomic

number, atomic mass, proton, neutron, electron, ion, cation, anion, isotope, metal, nonmetal,metalloid, molecule, compound, ionic bond, covalent bond, chemical reaction, acid, base, pH,

organic compound, inorganic compound, cell, metabolism, wavelength, photosynthesis, cellularrespiration, population, biological community, ecosystem, productivity, biomass, autotrophs,

primary producers, consumers, heterotrophs, food web, trophic level, herbivores, carnivores,

omnivores, detritivores, decomposers, ecological pyramid, biogeochemical cycle, chemical

cycle, carbon sink, nitrogen fixing, nitrite, nitrate, de-nitrification, ammonia, ammonium ion,


1. What is the conservation of matter?2. Compare and contrast kinetic and potential energy.

3. How is heat involved in the two laws of thermodynamics studied in class?

4. Explain the first law of thermodynamics.5. Explain the second law of thermodynamics.

6. Compare and contrast oxidation and reduction chemical reactions.

7. What is the miracle of water?8. What are the four major classes of biologically important organic compounds?

9. What is the source of energy for life?

10. Explain the various types of electromagnetic radiation or spectrum.

11. Compare and contrast photosynthesis to cellular respiration.12. Compare and contrast a closed system versus an open system.

13. What are the basic components needed for a functioning ecosystem?

14. What are the various ways of observing the various ecological pyramids?15. Explain the hydrologic cycle

16. Explain the carbon cycle

17. Explain the nitrogen cycle.18. Explain the phosphorus cycle

19. Explain the sulfur cycle.

Chapter 3


15/29

Terms to know:

Evolution, critical factors, tolerance limits, natural selection, adaptation, adapt, selectionpressure, habitat, ecological niche, competition, predation, predator, symbiosis, commensalisms,

mutualism, Batesian mimicry, Mullerian mimicry, keystone species, exponential growth, biotic

potential, carrying capacity, overhoots, dieback, primary productivity, diversity, resilience,stability, community structure, edge effect, ecotones, pioneer species, ecological development,

climax communities, community change


1. Explain what the tolerance limits for species.

2. What are the factors that cause selection pressure?

3. Compare and contrast divergent evolution from convergent evolution.4. What are the major taxonomic categories naming organisms?

5. What is resource partitioning for organisms?

6. What are the types of species interactions?

7. What are the various types of defensive mechanisms for organisms?8. What is the function of keystone species?

9. What is the shape of an exponential growth curve versus logistical growth curve?10. What are some of the limiting factors for populations? How does environmental

resistance relate to limiting factors?

11. What are the characteristics of a r-adapted species?

12. What are the characteristics of a k-adapted species?13. What is the edge effects for environmental and biotic communities?

14. Explain primary succession for a community?

15. Explain secondary succession for a community?

Human PopulationBomb or Bust?

Chapter 4

Population Growth 4 to 5 children born every second

2 people die every second

Net growth 2.5 children per second 150 per minute

9000 per hour (11,250 in a class period)

Overpopulation? Resource depletion

Environmental degradation

World Population Growth and Doubling Times

What type of Growth?


16/29

Logistic or Exponential?

Doubling Time Rule of 70

70 = doubling time in years

Percent growth

World Population and History

Malthusian Principle Reverend Thomas Malthus, 1798

An Essay on the Principle of Population Refute egalitarian principle of utopia (believing in human equality in a place of

ideal perfection)

Human population increasing at exponential or compound rate, food production

remained stable or increases only slowly. Human population will out strip food supply, collapse into starvation, crime,

and misery

Malthus vs. Karl MarxNeo-Malthusians

Malthusian view = we have reached the carrying capacity of the earth

David Pimentel 2100, 12 billion people, sick and dying

optimum 2 billion population at the beginning of WWII

Mohandas Gandhi There is enough for everyones need, but not enough for anyones greed

Can Technology save us? Advances in Agriculture has increase food production

Famines now are not natural but political

Availability of food based on easily acquired natural resources, cheap

fossil fuels. Alternative fuels or starvation?

Human Demography Demography Greekdemos= peopleandgraphein= to write or tomeasure

Vital Statistics Birth

Deaths


17/29

Where people live

World population distribution

World population distribution 2

Population Measures Crude birth rate = number of births in a year per 1000 persons

Crude because it is not adjusted for the number of women of reproductive age

Total fertility rate = the number of children born to an average woman

in the population during her entire reproductive life.

Zero population growth ZPG Chinas one-child-per-family policy

Fertility rate 1970 = 6

Fertility rate 1990 = 1.8

Human rights violation? Forced abortions

Forced sterilizations

Infanticide boys for the Family name sake Social/Cultural shift for China

Dr. As prediction = China will be transformed as Chinese women shortage brings back the

unwanted Chinese girls.

Adoption of Chinese girls to parents in other countries.

Crude death rate crude mortality rate = number of deaths per 1000 persons

Net population growth the difference between the crude birth rate and the

crude death rate.

What is the net population growth of country X which has a crude birth rate of

40/1000 and the crude death rate of 25/1000?

What is the percent growth rate for this population?

What is the doubling time for this population?

What is the net population growth of country X which has a crude birth

rate of 40/1000 and the crude death rate of 25/1000?

40 25 = 15/1000

What is the percent growth rate for this population?


18/29

15/1000 = 0.015 x 100 = 1.5%

What is the doubling time for this population?

70/1.5 = 46.7 years

Life span = the oldest age to which a species is known to survive.

Life expectancy = the average age that a newborn infant can expect to attain in any givensociety. The average age at death.

Early societies = 35 to 40 years

U.S. Life Expectancy

Income and life expectancy

Age Structure

More population measures Dependency ratio = the number of non-working compared to working

individuals in a population Developing countries workers are supporting high numbers of children

Developed countries workers are supporting higher numbers of retired

persons If you retire at age 65, you will be retired 35 to 40 years.

Changing age structure of the world

Population Growth Opposing factors Pronatalist pressures factors that increase peoples desires to havebabies Joy of babies

Support for elderly parents

Children help the family, tend livestock, etc.

High infant mortality

Male pride big families (11 to 12 children)

Birth reduction pressure

Higher education

Personal freedom

Spend time, goods, money than children

Education and socioeconomic status inversely related to fertility in rich

countries


19/29

Education and socioeconomic status in developing countries can increase

fertility because they can afford to have more children

U.S. Demographic Transition

Demographic Transition Optimistic View

Demographic transition already has occurred in developing countries. Population controls already happening

Factors to help stabilize populations Growing prosperity and social reforms

Technology

History of developed countries teach developing countries

Modern communications

Pessimistic View

Lester Brown, Worldwatch Institute Demographic trap prevents developing countries from escaping the middle phase of

transition Human demands exceed the sustainable yield of resources

Environmental deterioration, economic decline, political instability prevent

modernization Population grows until catastrophe intervenes

Need for birth control education and national encouragement for lower birth rates

Social Justice View

Fair share of social benefits for everyone

Enough resources for all, maldistribution of resources right now

Stressing overpopulation encourages racism and hatred of the poor

1994 International Conference on Population and

Development

180 participating countries To slow population growth

Responsible economic development

Education and empowerment of women

High-quality health care (including family-planning services) must be

accessible to everyone (this will lower infant mortality rate)


20/29

Family planning Couples determine the number and spacing of their children, plan

when children are born.

Birth Control become essential part of family planning

Fertility Controls Traditional controls

Breast feeding 3 to 4 years suppresses ovulation, (does not suppress in well

fed women)

Taboos against intercourse while breast-feeding

Celibacy

Abortions

Infanticide

Current Fertility controls

Avoidance of intercourse during fertile periods Celibacy, rhythm method, body temperature, etc.

Mechanical barriers Condoms, spermicides, diaphragms, cervical caps, vaginal sponges

Surgical methods to prevent sperm and/or egg release Tubal ligation in females, vasectomies in males

Chemicals that prevent maturation or release of sperm or egg or prevent embryo

implantation in the uterus Estrogen plus progesterone for females, gossypol for males

Birth control pills RU486

The Patch progesterone released through the skin

What is being used?The future of the Human population

So do you even care? Should we be worried about population growth?

Show the human population be controlled?

How does human population affect the worlds environments?The effect

If every person in the U.S. produced 1 cup of urine each day that

would have been on January 1, 2003 (U.S. population on Jan. 1 was

281,489,436 persons) a total of 17,593,090 gallons. This would be


21/29

equivalent to filling a swimming pool the size of a football field to the

depth of 104 feet deep each day. This urine would weigh 281,489 tons

Biomes and BiodiversityChapter 5

Biome Life zones, environments with similar climatic, topographic, and soil

conditions, roughly comparable biological communities

Biomes and Climate conditions

Temperature vs. PrecipitationLatitude and Altitude on Climate/Biomes

DesertsGrasslands Tropical grasslands

Savanna

Grazing

Browsing

Temperate grasslands

Prairies

Tall-grass

Short-grass Pampas

Veldt

Steppes

Polar Grasslands

Arctic tundra

Permafrost

Climate and Plants Deserts succulent plants

Rain Forest Broadleaf Evergreen plants Areas with winter Broadleaf Deciduous plants

Areas with short summer Coniferous or Evergreen plants

Forests Tropical Rain Forest

Tropical Deciduous Forest


22/29

Tropical monsoon forest

Tropical seasonal forest

Tropical Scrub forests Temperate Deciduous forests

Evergreen Coniferous Forests

Boreal Forests

Taigas

Evergreen Scrub Mediterranean

Chaparral thicket, California

Thorn scrub - Africa

Ocean life zones

Coastal Wetlands

Salt Marsh

BeachesSandy Beach Barrier Island

Reef

Freshwater Lakes

Freshwater Streams

Wetlands Ecosystem in which the land surface is saturated or covered with standing water

at least part of the year.

Swamps

Marshes

Biodiversity Genetic diversity measure of the variety of genes in a species

Species diversity number of different kinds of organisms

Ecological diversity richness and complexity of community

How many species are there?Biodiversity Hot Spots

How do we benefit from biodiversity? Food

Drugs and Medicines


23/29

Ecological Benefits

Aesthetic and Cultural Benefits

Threat to Biodiversity Extinction

Causes of: Continental drift

Climate change

Catastrophes

Background extinction

Mass extinction Adaptive radiation

Human-caused reduction in Biodiversity

Habitat Destruction Fragmentation

Island Biogeography R.H. MacArthur

E.O. Wilson

Hunting and Fishing Passenger Pigeons

Commercial Products and Live Specimens Economic value

Predator and Pest Control Introduction of Exotic Species

Kudzu

Zebra mussels

Diseases Fungal blight American chestnut

Pollution

Genetic Assimilation Crossbreeding

Protecting Biodiversity Hunting and Fishing laws

Endangered Species Act World Conservation Union

U.S. Fish and Wildlife Service

Endangered species


24/29

Threatened species

Vulnerable species

Threatened Species of the world 34% of worlds fish

25% of amphibians 25% of mammals

20% of reptiles

13% of plants

11% of birds

Protecting Biodiversity Recovery plans

Reintroductions Minimum Viable population

Founder effect genetic diversity may not be viable

Demographic bottleneck genetic problems

Genetic drift

Inbreeding genetic diseases

Private land and Critical Habitat

Food and AgricultureWill there be enough nutritious food for everyone?

Chapter 7

Golden Rice Genetically modified organisms

Frankenfoods? Unnatural creations?

Overweight Overfed = Underweight - Underfed Lower life expectancy

Increased susceptibility to disease and illness Reduced productivity and life quality

Terms of nutrition Undernutrition = people who cannot grow or buy enough food to meet their

basic energy needs Proper amount of calories

Proper amounts of protein, carbohydrates, fats, vitamins, and minerals


25/29

Chronically undernourished less than 90% of minimum Caloric intake needed for

normal growth and development

Malnutrition nutritional imbalance, enough calories, lack of specific dietary

components

Nutrient-deficiency diseases mainly protein Marasmus to waste away, low calories and proteins

Thin and shriveled, tiny starving people

Kwashiorkor displaced child, protein deficiency, weaned children, enough calories, not

enough proteins Reddish-orange hair, puffy discolored skin, bloated belly

Overnutrition food energy intake exceeds energy use. Second leading cause of

premature death Obesity 30 lbs. Above normal weight

Poverty CycleSystems that provide us with food.

Croplands produce grain

Rangelands produce meat, livestock

Oceanic fisheries

What feeds us? 15 plants species

Main grain crops = wheat, rice, corn Annual species

8 terrestrial animal species Developed countries beef, pork, and chicken, eggs, milk, and cheese

domestic livestock

90% of our food.

Major types of food productionHigh-input agriculture

Industrialized agriculture

Large amounts of fossil fuels, water, commercial fertilizers, and pesticides Monoculture 25% of croplands Plantation agriculture

Bananas, coffee, cacao

Livestock farming feedlots

Traditional

Traditional subsistence agriculture Produce enough food for their own family


26/29

Very little surplus

Traditional intensive agriculture More human and animal power input, more water and fertilizers

Farm to have surplus, mainly women labor

Food Production

Food Production

Food production - 2

Food outlooks We can provide the basic nutritional needs of every person on the

earth today. If distributed equally. Meatless subsistence

Principle cause of hunger is poverty

SoilsSoil Profile

Factors of Soils Soil porosity space between grains

Soil permeability ability of fluid to flow through it

Soil structure how soil particles are organized and clumped

Soil Types

Soil Erosion

Mechanical Erosion Sheet erosion

Rill erosion

Gully erosion

Soil erosion reduction

Gully reclamation Windbreaks

Shelterbelts

PAM polyacrylamide, added to irrigation water to reduce soil

erosion

Desertification


27/29

Factors

Overgrazing

DeforestationSurface mining without reclamation

Irrigation techniques

Farming marginal soilsSoil compaction

Drought

FamineDeclining living standards

Increased refugees

Salt build up salinization waterlogging

Soil Conservation

Conventional-tillage farming Conservation-tillage farming Minimum-tillage

No-till farming

Terracing

Contour farming

Strip cropping

Ally cropping

Agrodiversity - interplanting Growing several crops on the same plot of land

Polyvarietal cultivation several varieties of the same crop

Intercropping two or more different crops grown

Agroforestry ally cropping crops and trees grow together, fruit trees and grains,fuelwood and other crops

Polyculture different plants which mature at different times are grown together. Year-

round plant cover to the soil

Soil Fertility Organic fertilizer

Animal manure

Green manure Compost

Commercial Inorganic fertilizers


28/29

Crop Rotation

Agriculture Environmental impact Agriculture has a greater harmful impact on air, soil, water and

biodiversity resources than any other human activity.Not included in the cost of food

Major environmental effects from food production

Green Revolution Farm more land

Get higher yields per unit area Developing and planting monocultures, selectively breed or genetically

engineered 3 grains

Heavy fertilizer, pesticides, and water use

Increase intensity and frequency of cropping

Green Revolutions

Effects from the Green Revolution Soil erosion

Loss of fertility of the soil

Salination and waterlogging

Depletion of water resources groundwater and surface water

Increase of rapidly breeding pests, develop immunity to pesticides

Increasing crop yields Gene Revolution Crops that:

Are more resistant to insects and disease

Thrive on less fertilizer

Make their own nitrogen fertilizer

Do well in slightly salty soils

Can withstand drought

Use solar energy more efficiently during photosynthesis

Are you willing to eat? Genetically modified organisms?

New forms of vegetables?

Insects? Microlivestock

Mopani anyone? Emperor moth catepillars


29/29

Sustainable approaches Sustainable Agriculture

Regenerative farming

Low-Input sustainable agriculture Less mechanized farming

Documents

Enviroment Notes