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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