food, soil, and pest management chapter 12. soil: the foundation for agriculture land devoted to...

Food, Soil, and Pest Management

Chapter 12

Soil: the foundation for agriculture

Land devoted to agriculture covers 38% of Earth’s land surface

Agriculture = practice of raising crops and livestock for human use and consumption

Cropland = land used to raise plants for human use Rangeland or pasture = land used for grazing

livestock Soil = a complex plant-supporting system consisting

of disintegrated rock, organic matter, water, gases, nutrients, and microorganism • It is a renewable resource

Soil as a system

Soil consists of mineral matter, organic matter, air, and water and is formed by:• Dead and living

microorganisms, and decaying material

• Bacteria, algae, earthworms, insects (decomposers), mammals, amphibians, and reptiles (burrowing animals)

Since soil is composed of living and non-living matter, it is considered an ecosystem

Soil formation is slow and complex

Parent material = the base geologic material of soil• Mostly rock and sediments • Derived from weathered bedrock in unglaciated

areas Weathering = the physical, chemical, or biological

processes that break down rocks to form soil• Physical (mechanical) = wind and rain, no

chemical changes in the parent material• Chemical = substances chemically interact with

parent material• Biological = organisms break down parent material

Weathering produces soil

Other processes affect soil formation Erosion = the movement of soil by wind or water

• Removes topsoil• Occurs when vegetation is absent

Biological activity includes deposition, decomposition, and accumulation of organic matter• Humus = a dark, spongy, crumbly mass of organic

material formed by partial decomposition

A soil profile consists of horizons

Horizon = each layer of soil Soil profile = the cross-

section of soil as a whole Up to six major horizons may

occur in a soil profile• Topsoil = inorganic and

organic material most nutritive for plants (A)

• Leaching = dissolved particles move down through horizons (E to B)

Soils are characterized in many ways Soils are classified based on color, texture,

structure, and pH Soil color = indicates its composition and fertility

• Black or dark brown = rich in organic matter• Pale gray or white = indicates leaching

Soil texture = determined by the size of particles• From smallest to largest = clay, silt, sand• Loam = soil with an even mixture of the three• Influences how easy it is to cultivate and let air and

water travel through the soil (porosity & permeability)

Soil texture classification

Silty soils with medium-size pores, or loamy soils with mixtures of pore sizes are best for plant growth and crop agriculture

Soil structure

Soil structure = a measure of soil’s “clumpiness”• Large clumps can discourage plant roots (tend to be

higher in clay)• Repeated tilling compacts soil, decreasing its water-

absorbing capabilities (permeability)• Plowpan = a hard layer resulting from repeated

plowing that resists water infiltration and root penetration

Soil pH

Soil pH = influences a soil’s ability to support plant growth• Soils that are too acidic or basic can kill plants• Soils deficient of humus have a higher pH

• As rain water percolates down through the humus it forms tannic acid from dead leaves and bark. This weak acid has a pH of about 6.

Cation exchange is vital for plant growth

Cation exchange = process that allows plants to gain nutrients• Negatively charged soils hold cations (positively

charged ions) of Ca+, Mg+, and K+ Cation exchange capacity = a soil’s ability to hold

cations, preventing them from leaching, thereby increasing their availability to plants

• A useful measure of soil fertility• Greatest in fine soils• Diminishes with lower pH

Regional differences in soils affect agriculture Rainforests have high primary

productivity, but when cleared rain leaches minerals and nutrients deeper into the soil, reducing their accessibility to roots• Swidden agriculture =

cultivation of a plot for a few years and then letting it regrow into forest

Temperate grasslands (prairies) have lower rainfall and less nutrient leaching thus higher productivity

Prairie profile

Erosion degrades ecosystems and agriculture

Erosion increases through: excessive tilling, overgrazing, and clearing forests (anything that exposes the soil)

In agriculture the greatest concern is the removal of topsoil (no topsoil = poor crop growth)

Soil erodes by several methods Removing plants accelerates erosion Rill erosion moves the most topsoil, followed by

sheet and splash forms of erosion Water erosion occurs most easily on steep slopes Erosion in the U.S. declined between 1982 and 2001

• Soil conservation measures

Despite conservation measures, the U.S. still loses 6 tons of soil for every ton of grain harvested

Various types of soil erosion

SplashSheetRillGully

Soil erosion is a global problem Humans are the primary cause of erosion

• It is occurring at unnaturally high rates In Africa, erosion over the next 40 years could reduce

crop yields by half• Coupled with rapid population growth, some observers

describe the future of agriculture as a crisis situation

Desertification

Desertification = a loss of more than 10% productivity• Erosion, soil compaction,

forest removal, overgrazing, salinization, climate change, depletion of water sources

Most prone areas = arid and semiarid lands

Desertification has high costs

Desertification affects 1/3 of the planet’s land area• In over 100 countries

Costs tens of billions of dollars each year• China loses over $6.5 billion/year alone from goat

overgrazing• In Kenya, 80% of the land is vulnerable to

desertification from overgrazing and deforestation

The Dust Bowl In the late 19th and early

20th centuries, settlers arrived in Oklahoma, Texas, Kansas, New Mexico and Colorado

Grew wheat, grazed cattle• Removed vegetation

A drought in the 1930s made conditions worse

Thousands of farmers left their land and had to rely on governmental help

Shelterbelts

• Shelterbelts were planted extensively after the Dust Bowl.• Fast growing trees such as the Lombardy Poplar break the force of the wind and help stabilize soil.

The Soil Conservation Service Started in 1935, the Service works with farmers to

develop conservation plans for farms• Prepare an integrated plan• Implement conservation measures

Conservation districts = districts operate with federal direction, authorization, and funding, but are organized by the states

Natural Resources Conservation Service = 1994 renaming of the Soil Conservation Service• Expanded responsibilities include water quality

protection and pollution control

Protecting soil: crop rotation and contour farming

Crop Rotation = alternating the crops grown from one season to the next, • Cover crops protect soil when

main crops aren’t planted• Wheat or corn and soybeans

Contour Farming = plowing furrows sideways across a hillside, perpendicular to its slope, to prevent rills and gullies

Protecting soil: terracing and intercropping Terracing = level platforms

are cut into steep hillsides, sometimes with raised edges• A “staircase” to contain

water reduces erosion Intercropping = planting

different types of crops in alternating bands or other spatially mixed arrangements• Increases ground cover

Protecting soil: shelterbelts and reduced tillage

Shelterbelts or Windbreaks = rows of trees or other tall, perennial plants that are planted along the edges of fields to slow the wind• Alley cropping = shelterbelts +

intercropping Reduced Tillage = furrows are cut

in the soil, a seed is dropped in and the furrow is closed• No-till farming disturbs the soil

even less

No-till agriculture in Southern Brazil

Southern Brazil’s climate and soils make for bountiful harvests but repeated planting has diminished the productivity of the soil

Leaving crop residues on their fields after harvesting and planting “cover crops” reduced erosion, increased yields and cut cost

Pros and cons of no-till farming

Almost half of U.S. farmland uses no-till farming

Benefits: reduced soil erosion, greater crop yields, enhanced soils

Negatives: increased use of herbicides and fertilizers

But, green manure (dead plants and fertilizer) and rotating crops minimizes the negatives

Plant cover reduces erosion

Eroding banks along creeks and roadsides are stabilized by planting plants to anchor soil

China has the world’s largest tree-planting program • It does slow erosion• But it does not create

ecologically functional forests, because monocultures are planted

Irrigation: boosted productivity, but problems, too

Irrigation = Artificially providing water to support agriculture• Unproductive regions

become farmland Waterlogging = over-irrigated

soils • Water suffocates roots

Salinization = the buildup of salts in surface soil layers• Worse in arid areas

Salinization inhibits production of 20% of all irrigated cropland, costing more than $11 billion/year

Salinization prevention

It is easier and cheaper to prevent salinization than fix it

Do not plant water-guzzling crops in sensitive areas

Irrigate with low-salt water Irrigate efficiently, supplying

only water that the crop requires• Drip irrigation targets

water directly to plants

Fertilizers boost yields but cause problems

Fertilizer = substances that contain essential nutrients Inorganic fertilizers = mined or synthetically manufactured mineral

supplements Organic fertilizers = the remains or wastes of organisms

• manure, crop residues, fresh vegetation• Compost = produced when decomposers break down organic

matter • Never add waste from butchering animals to compost

Applying synthetic fertilizer, vs.Planting rye, a “green manure”

Overapplication of Fertilizer

Inorganic fertilizer use has skyrocketed

Overapplying fertilizer can ruin the soil and severely pollute several areas

Runoff causes eutrophication in nearby water systems

Nitrates leach through soil and contaminate groundwater

Nitrates can also volatilize (evaporate) into the air

Environmental effects of over-fertilizing

Overgrazing causes soil degradation

Overgrazing = too many animals eat too much of the plant cover • Impedes plant regrowth

A leading cause of soil degradation

Government subsidies provide few incentives to protect rangeland

70% of the world’s rangeland is classified as degraded

U.S. programs promote soil conservation

Food Security Act of 1985: Farmers that adopt soil conservation plan receive price supports and other benefits

Conservation Reserve Program (1985)• Farmers are paid to place highly erodible land into

conservation reserves• Trees and grasses are planted instead of crops• Saves 771 million tons of topsoil per year• Generates income for farmers • Provides habitat for native wildlife

Federal Agricultural Improvement Act (1996)

Known as the Freedom to Farm Act• Aimed to reduce subsidies and government influence over farm

products• Created the Environmental Quality Incentive Program and

Natural Resource Conservation Foundation• Promotes and pays for conservation practices in agriculture

Low-Input Sustainable Agriculture Program (1998)• Provides funding for sustainable agricultural practices for

individual farmers

International soil conservation programs

Food and Agriculture Organization (FAO) = the United Nations’ main agricultural program

The FAO’s Farmer-Centered Agricultural Resource Management Program (FAR)…• Helps farmers duplicate agricultural success stories• Uses local communities to educate and encourage

farmers to conserve soils and secure the food supply• Supports innovative approaches to resource management

and sustainable agriculture in around the world• China, Thailand, Vietnam, Indonesia, Sri Lanka, Nepal

Today, we are producing more food per person

Food production currently exceeds population growth We produce food through technology

• Fossil fuels, irrigation, fertilizer, pesticides, crossbreeding

Predictions of mass starvation in 1960s did not happen

Food security

Food security = the guarantee of adequate and reliable food supply to all people at all times

Fewer people today are hungry than in 1970 We have reduced hunger by half since 1970

• But, 850 million people still go hungry

Since 1985, world grain production has fallen by 9%

We face both too little and too much food

Undernourishment = people receive less than 90% of their daily caloric needs• Mainly from economic reasons in developing countries• 31 million Americans are food insecure

Overnutrition = receiving too many calories• In the U.S., 25% of adults are obese• Worldwide, more than 300 million people are obese

Malnutrition = a shortage of nutrients the body needs• The diet lacks adequate vitamins and minerals

Many People Suffer from Chronic Hunger and Malnutrition

Macronutrients• Carbohydrates• Proteins• Fats

Micronutrients• Vitamins• Minerals

Many People Do No Get Enough Vitamins and Minerals

Most often vitamin and mineral deficiencies in people in developing countries

Iron

Vitamin A

Iodine

Golden rice

Malnutrition

Vitamin A deficiency in some developing countries leads to• Blindness• Death

1999: Porrykus and Beyer• Genetically engineered rice with beta-carotene and

more iron

Is this the answer for malnutrition in these countries?

Challenge of increased food production

Acute Food Shortages Can Lead to Famines

Famine• Usually caused by crop failures from

• Drought• Flooding• War• Other catastrophic events

Many People Have Health Problems from Eating Too Much

Overnutrition

Similar health problems to those who are underfed• Lower life expectancy • Greater susceptibility to disease and illness• Lower productivity and life quality

Quantity and quality of food is important Kwashiorkor = diets

lacking protein or essential amino acids• Occurs when children

stop breast-feeding• Bloated stomach, mental

and physical disabilities Marasmus = protein

deficiency and insufficient calories • Wasting or shriveling of

the body

The green revolution

Dramatically increased per-acre yields

Spread to the developing world in the 1940s with wheat, rice, corn

Depended on large amounts of• Synthetic fertilizers • Chemical pesticides • Irrigation • Heavy equipment

The green revolution brought benefits and harm From 1900 to 2000, cultivated area increased 33%,

while energy inputs increased 80 times! Positive effects on natural resources

• Prevented some deforestation• Preserved biodiversity

Negative effects on natural resources • Pollution• Erosion• Salinization• Desertification

The green revolution in India

Between 1961 and 2003• Population increased 100%• Food production increased 150%

As a result of the green revolution, India became a grain exporter

Monocultures increase output, but at a cost

Monoculture = a large expanse of a single crop• More efficient, increases output• Devastates biodiversity• Susceptible to disease and pests

Narrows human diet: 90% of our food comes from 15 crop species and 8 livestock species

Armyworms easily defoliate monocultures

Pests and pollinators

Pest = any organism that damages valuable crops

Weed = any plant that competes with crops Pesticides = poisons that target pest organisms

• Insecticides = target insects• Herbicides = target plants• Fungicides = target fungi

400 million kg (900 million lbs.) of pesticides are applied in the U.S. each year• 75% of this is applied to agricultural land• Usage is increasing in developing countries

Resistance to pesticides

Some individuals are genetically immune to a pesticide- They survive and pass these genes to their offspring

Pesticides stop being effective - Evolutionary arms race: chemists increase

chemical toxicity to compete with resistant pests

Biological control

Biological control (Biocontrol) = uses a pest’s natural predators to control the pest• Reduces pest populations

without chemicals• Cactus moths control

prickly pear• Bacillus thuringiensis

(Bt) = soil bacteria that kills many pests

Biocontrol agents may become pests themselves

No one can predict the effects of an introduced species

The agent may have “nontarget” effects on the environment and surrounding economies• Cactus moths are eating rare Florida cacti

Removing a biocontrol agent is harder than halting pesticide use• Due to potential problems, proposed biocontrol use

must be carefully planned and regulated

Integrated Pest Management (IPM)

IPM uses multiple techniques to suppress pests- Biocontrol- Chemicals, when

necessary- Population monitoring - Habitat alteration- Crop rotation and

transgenic crops- Alternative tillage methods- Mechanical pest removal

Within 4 years of using IPM in Indonesia, rice yields rose 13%, and $179 million saved by phasing out subsidies

We depend on insects to pollinate crops

Not all insects are pests; some are absolutely vital• 800 cultivated plant species rely on insect

pollinators Pollination = male plant sex cells fertilize female

sex cells• By wind or animals

Pollinators include:• Hummingbirds• Bats• InsectsFlowers are evolutionary adaptations to attract pollinators

Conservation of pollinators is vital

Native populations of pollinators have plummeted Honeybees pollinate more than 100 crops – 1/3 of the U.S.

diet. - In 2006, hives died off

To conserve bees:- Reduce or eliminate pesticide use - Plant flowering plants

Genetically modified organisms

Genetic engineering = laboratory manipulation of genetic material

Genetically modified organisms = organisms that have been genetically engineered by …

Recombinant DNA = DNA created from multiple organisms

Genetic engineering has both benefits and risks Benefits of genetic engineering:

• Increased nutritional content• Increased agricultural efficiency• Rapid growth• Disease and pest resistance

Negatives of genetic engineering:• Risks are not yet defined or well understood• Protests from environmental activists, small farmers,

and consumer advocates

Biotechnology is impacting our lives

Biotechnology = the material application of biological science to create products derived from organisms

Transgenic organism = an organism that contains DNA from another species • Transgenes = the genes that have moved between

organisms Biotechnology has created medicines, cleaned up

pollution, and dissolves blood clots

Some genetically modified foods

Genetic engineering versus agricultural breeding Artificial selection has influenced the genetic makeup of

livestock and crops for thousands of years Proponents of GM crops say GM foods are safe Critics of GM foods say:

• Traditional breeding uses genes from the same species• Selective breeding deals with whole organisms, not just

genes

• In traditional breeding, genes come together on their own

Traditional breeding changes organisms through selection, while genetic engineering is more like the process of mutation

Biotechnology is changing our world

GM foods become big business Most GM crops are herbicide resistant

• Farmers apply herbicides to kill weeds, and crops survive• Most U.S. soybeans, corn, cotton, and canola are genetically

modified

Globally, more than 10 million farmers grew GM foods on 102 million ha of farmland, producing $6.15 billion worth of crops

What are the impacts of GM crops?

As GM crops expanded, scientists and citizens became concerned• Dangerous to human health• Escaping transgenes could pollute ecosystems and

damage nontarget organisms• Pests could evolve resistance• Could ruin the integrity of native ancestral races• Interbreed with closely related wild plants

Supporters maintain that GM crops are safe

Supporters make the following points:• GM crops pose no ill health effects• They benefit the environment by using less herbicides • Herbicide-resistant crops encourage no-till farming• GM crops reduce carbon emissions by needing fewer

fuel-burning tractors and sequestering carbon in the soil by no-till farming

Critics argue that we should adopt the precautionary principle = don’t do any new action until it’s understood

Studies on GM foods show mixed results

Between 2003 and 2005, the British government commissioned three large-scale studies, which showed• GM crops could produce long-term financial benefits• Little to no evidence was found of harm to human

health, but effects on wildlife and ecosystems are not well known

• Bird and invertebrate populations in GM fields were mixed; some crops showed more diversity, some less, depending on the crop

The GM debate involves more than science

Ethical issues plays a large role• People don’t like “tinkering” with “natural” foods• With increasing use, people are forced to use GM

products, or go to special effort to avoid them• Multinational corporations threaten the small farmer• Research is funded by corporations that will profit if

GM foods are approved for use• Crops that benefit small, poor farmers are not widely

commercialized

The GM industry is driven by market considerations of companies selling proprietary products

GMO producers are suing farmers

Monsanto has launched 90 lawsuits against 147 farmers, winning an average $412,000 per case • Monsanto charged farmer Percy Schmeiser of

Canada with using its patented GM seeds without paying for them

• Schmeiser charged the seeds blew onto his field from the neighbor’s adjacent field

• The courts sided with Monsanto, saying Schmeiser had violated Monsanto’s patent

Farmers say that “[they] are being sued for having GMOs on their property that they did not buy, do not want, will not use, and cannot sell”

Nations differ in their acceptance of GM foods

Europe opposed GM foods• The U.S. sued the European Union before the World

Trade Organization, charging that the European Union was hindering free trade

• Brazil, India, and China approve GM crops• Zambia refused U.S. food aid, even though people

were starving, because some seeds were genetically modified

Preserving crop diversity: insurance against failure Preserving native variants protects against crop failure

• Monocultures are vulnerable, so wild relatives contain genes that could provide resistance to disease and pests

We have already lost a great deal of genetic diversity in crops• Wheat varieties in China dropped from 10,000 (1949) to

1,000 (1970s) Market forces discourage diversity in food’s

appearance• Consumers prefer uniform, standardized food

Preserving crop diversity: seed banks Seed banks = institutions that preserve seed types as a kind of

living museum of genetic diversity• Seeds are collected and preserved, and periodically planted• Funding is not adequate for these facilities

The Royal Botanic Garden’s Millennium Seed Bank in Britain holds more than 1 billion seeds

Eating animal products has significant impacts As wealth and commerce increase, so does

consumption of meat, milk, and eggs• Global meat production has increased fivefold• Per capita meat consumption has doubled

Domestic animal production for food increased from 7.3 billion in 1961 to 20.6 billion in 2000

Feedlot agriculture

Feedlots (factory farms) = also called Concentrated Animal Feeding Operations (CAFOs)• Huge warehouses or pens

designed to deliver energy-rich food to animals living at extremely high densities

• Over ½ of the world’s pork and poultry come from feedlots

Debeaked chickens spend their lives in cages; U.S. farms can house hundreds of thousands of chickens in such conditions

The benefits and drawbacks of feedlots

The benefits of feedlots include:• Greater production of food• Unavoidable in countries with high levels of

meat consumption, like the U.S. • They take livestock off the land and reduces

the impact that they would have on it Drawbacks of feedlots include:

• Contributions to water and air pollution• Poor waste containment causes outbreaks in

disease• Heavy uses of antibiotics to control disease

Energy choices through food choices

90% of energy is lost every time energy moves from one trophic level to the next

The lower on the food chain from which we take our food sources, the more people the Earth can support.

Some animals convert grain into meat more efficiently than others

Environmental ramifications of eating meat Land and water are needed to raise food for livestock Producing eggs and chicken meat requires the least

space and water• Producing beef requires the most

When we choose what to eat, we also choose how we use resources

Aquaculture

World fish populations are plummeting• Technology and

increased demand Aquaculture = raising

aquatic organisms for food in a controlled environment• Aquatic species are

raised in open-water pens or land-based ponds

Aquaculture is growing rapidly The fastest-growing type of food production

• Provides a third of the world’s fish for human consumption

• Most widespread in Asia

The benefits and drawbacks of aquaculture Benefits:

• A reliable protein source• Sustainable • Reduces fishing pressure

on overharvested wild fish stocks

• Energy efficient

Drawbacks:• Diseases can occur,

requiring expensive antibiotics

• Reduces food security• Large amounts of waste• Farmed fish may

escape and introduce disease into the wild

Sustainable Agriculture

Industrial agriculture may seem necessary, but less-intensive agricultural methods may be better in the long run

Sustainable agriculture = does not deplete soil, pollute water, or decrease genetic diversity

Low-input agriculture = uses smaller amounts of pesticide, fertilizers, growth hormones, water, and fossil fuel energy than industrial agriculture

Organic agriculture = Uses no synthetic fertilizers, insecticides, fungicides, or herbicides• Relies on biological approaches (composting and

biocontrol)

A standardized meaning for “organic” People debate the meaning of the word “organic”

• Organic Food Production Act (1990) establishes national standards for organic products

• The USDA issued criteria in 2000 by which food could be labeled organic

• Some states pass even stricter guidelines for labeling

The market for organic food is increasing

Sales increased 20%/year in Canada and the U.S. from 1989-2005• Expanded by a factor of 40

in Europe Amount of land for organic

farming is increasing• 10-35%/year in the U.S. and

Canada• In 2005 the U.S. had 1.7

million acres of organic cropland and 2.3 million acres of organic pastureland

The benefits of organic farming For farmers:

• Lower input costs, enhanced income from higher-value products, reduced chemical costs and pollution

• Obstacles include the risks and costs of switching to new farming methods and less market infrastructure

For consumers:• Concern about pesticide’s health risks• A desire to improve environmental quality• Obstacles include the added expense and less

aesthetically appealing appearance of the product

The U.S. doesn’t financially support organic farmers

In 1993, the European Union adopted a policy to support farmers financially during conversion to organic farming

The U.S. offers no such support• Organic production lags in the U.S.• Farmers can’t switch, because they can’t afford

the temporary loss of income• In the long run, organic farming is more profitable

Organic agriculture succeeds in cities

Community gardens = areas where residents can grow their own food

In Cuba, over 30,000 people work in Havana’s gardens, which cover 30% of the city’s land• Record yields for 10 crops in 1996-1997

Locally supported agriculture is growing

In developed nations, farmers and consumers are supporting local small-scale agriculture• Fresh, local produce in season

Community-supported agriculture = consumers pay farmers in advance for a share of their yield• Consumers get fresh food• Farmers get a guaranteed

income

Food Production Has Increased Dramatically

Three systems produce most of our food• Croplands: 77%• Rangelands, pastures, and feedlots: 16%• Aquaculture: 7%

Importance of wheat, rice, and corn

Tremendous increase in global food production

Industrialized Crop Production Relies on High-Input Monocultures

Industrialized agriculture, high-input agriculture• Goal is to steadily increase crop yield

• Plantation agriculture: cash crops• Increased use of greenhouses to raise crops

A Closer Look at Industrialized Crop Production

Green Revolution: increase crop yields• Monocultures of high-yield key crops

• E.g., rice, wheat, and corn

• Use large amounts of fertilizers, pesticides, and water

• Multiple cropping

Second Green Revolution

World grain has tripled in production

Food and Biofuel Production Systems Have Caused Major Biodiversity Losses

Biodiversity threatened when• Forest and grasslands are replaced with

croplands

Agrobiodiversity threatened when• Human-engineered monocultures are used

Importance of seed banks • Newest: underground vault in the Norwegian

Arctic

We Use Pesticides to Try to Control Pest Populations (2)

First-generation pesticides

Second-generation pesticides• Paul Muller: DDT• Benefits versus harm

Broad-spectrum agents

Persistence

Modern Synthetic Pesticides Have Several Advantages

Save human lives

Increases food supplies and profits for farmers

Work quickly

Health risks are very low relative to their benefits

New pest control methods: safer and more effective

Modern Synthetic Pesticides Have Several Disadvantages (1)

Accelerate the development of genetic resistance to

pesticides by pest organisms

Expensive for farmers

Some insecticides kill natural predators and

parasites that help control the pest population

Pollution in the environment

Some harm wildlife

Some are human health hazards

Modern Synthetic Pesticides Have Several Disadvantages (2)

David Pimentel: Pesticide use has not reduced U.S. crop loss to pests• Loss of crops is about 31%, even with 33-fold

increase in pesticide use• High environmental, health, and social costs with

use• Use alternative pest management practices

Pesticide industry refutes these findings

Laws and Treaties Can Help to Protect Us from the Harmful Effects of Pesticides

U.S. federal agencies• EPA• USDA• FDA

Effects of active and inactive pesticide ingredients are poorly documented

Circle of poison, boomerang effect

Reduce Soil Erosion

Soil conservation, some methods• Terracing• Contour planting• Strip cropping with cover crop• Alley cropping, agroforestry• Windbreaks or shelterbeds• Conservation-tillage farming

• No-till• Minimum tillage

Identify erosion hotspots

Buy Locally Grown Food

Supports local economies

Reduces environmental impact on food production

Community-supported agriculture