Environment in the News

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Agriculture and Food Resources

Chapter 7

[chapter opener image]

Chapter 14

Visualizing Environmental Science

Maintaining Grain Stocks for Food Security

World grain stocks provide a measure of food security

Grain stocks are remains of grains from previous harvests which provide a cushion against poor harvests and rising costs

Have been decreasing since 1980s—90s highs

Stockpile in 2010 would have fed the world for only 72 days

UN says it should not be below 70 days’ supply

Food security—having access at all times to adequate amounts and kinds of food needed for healthy, active lives

World Food Problems

At least 1 billion people in the world lack food for healthy, productive lives—2009 World Summit on Food Security

Most live in rural areas of poorest developing countries

182 million children under age 5 suffer from undernutrition—World Health Organization (WHO)

A type of malnutrition in which there is underconsumption of calories or nutrients that leaves the body weakened and susceptible to disease

Even if receiving enough calories, undernutrition happens if not enough essential nutrients: protein, vitamins, minerals

2 billion people worldwide suffer from micronutrient deficiencies

World Food Problems

Millions of children suffer from kwashiorkor, caused by severe protein deficiency. Note the characteristic swollen belly, which results from fluid retention. Photographed in Haiti.

Marasmus is progressive emaciation caused by a diet low in both total calories and protein. Symptoms include a pronounced slowing of growth and extreme wasting of muscles. Photographed in Somalia.

Globally, millions of adult men and women are hungry. This homeless man is suffering from severe malnutrition and starvation. Photographed in New Delhi, India.

World Food Problems

Overnutrition

A type of malnutrition in which there is overconsumption of calories that leaves the body susceptible to disease

Usually diets high in saturated fats, sugar, and salt

Results in high blood pressure, obesity, and increased likelihood of diabetes, heart disease, etc.

Mostly a problem in highly developed nations and in urban areas of developing nations

As income increases, people can afford more meats and sugars, so paradoxically, their diet can become less healthy even though they are better off financially

World Food Problems

Population and world hunger

66 countries are considered low income and food deficient

Cannot produce enough food, or afford to import it

Food insecurity—people live with chronic hunger and malnutrition

22 countries, primarily in sub-Saharan Africa commonly experience food insecurity

Experts agree that world hunger, population, poverty, and environmental problems are interrelated

Solutions—control population growth, promote economic development, correct inequitable distribution of resources

World Food Problems

Annual world grain production almost doubled from 1970–2011

But population has grown so that amount per person has not changed

By 2050, farmers will have to grow close to 30% more food to be able to feed 9.3 billion expected population

Available grain per person varies significantly per country

World Food Problems

Poverty and food

Main cause of undernutrition is poverty

Infants, children, and elderly are most susceptible to poverty and hunger

Poorest people do not own land to grow food, do not have money to purchase food

Poverty not restricted to developing nations

Solutions

Increase sustainable production of food

Improve food distribution

Achieve stable population size at a level the environment can support

The Principal Types of Agriculture

Industrialized agriculture

Utilized in highly developed and some developing countries

High-input—requires large capital and energy inputs, less land, and less manual labor than traditional methods

Significantly dependent on fossil fuels

Produces high yields

Monoculture cultivation predominates

Soil degradation, pesticide resistance common

The Principal Types of Agriculture

Subsistence agriculture

Utilized by most farmers in most developing countries

Traditional agricultural methods that depend on labor and a large amount of land

Just enough food to feed farmer and family

Cultivation methods vary depending on area

Shifting cultivation

Slash-and-burn agriculture

Nomadic herding

Intercropping

Polyculture

Challenges of Agriculture

U.S. has over 120 million hectares (300 million acres) of prime farmland

Has the soil type, growing conditions, available water to produce food, forage, fiber, oilseed crops

Challenges

Decline in farmland

Declining numbers of domesticated varieties

Continuing to improve crop and livestock yields

Addressing environmental impacts

Challenges of Agriculture

Victim of urbanization, suburban sprawl

Parking lots, housing developments, shopping malls

Farm Bill—1996

Farmland Protection Program

Voluntary sale of conservation easements to prevent farmland from being converted to non-agricultural uses (30 yrs–forever)

Farmers retain full rights to use their property for farming

Challenges of Agriculture

Global decline in domesticated plant and animal varieties

Replacement of many local varieties with just a few kinds of modern varieties bred for uniformity and maximum production

Loss of genetic diversity of nutritional value, size, color, flavor, resistance to disease, adaptability to climates and soil types

Germplasm conservation

Plant or animal material that may be used in breeding

Seeds, plants, plant tissues of traditional crop varieties

Sperm and eggs of traditional livestock breeds

Challenges of Agriculture

Increasing crop yields

Scientific advances since 1940s have increased food production dramatically in highly developed countries

Fertilizers, pesticides, higher yield plant varieties

Average U.S. wheat yields, 1950-2010

Challenges of Agriculture

Green revolution

1960s—high yield varieties of rice and wheat developed

Traditional rice plant on left—taller, lower grain yield

Hybrid in center (1960s)—higher yield, disease resistant

Rice plant on right (1990s)—high yield, disease resistant; shorter and stronger stalk to support heavier grain production without collapsing

Challenges of Agriculture

Green revolution

High yield grain varieties required intensive industrial agriculture

In the 1920s, Mexico produced less than 0.7 metric tons/ha

In 1965, Mexico’s wheat production rose to 2.4 metric tons/ha

Criticisms

Has made developing countries dependent on imported technologies at the expense of traditional agriculture

High energy costs

Environmental problems from excessive pesticide and fertilizer use

Challenges of Agriculture

Post-green revolution era

World’s demand for rice, wheat, corn will continue to increase into the future

Increasing amounts of grain needed for humans, livestock, and biofuel production

Cannot be met without increasing amount of farmland

Freshwater shortages, rising costs of agricultural chemicals, deteriorating soil quality

Scientists think it’s possible to develop higher yield varieties with sufficient investment

Modern agricultural methods must be introduced to developing countries to increase their crop yields

Challenges of Agriculture

Increasing livestock yields

Hormones promote faster growth

U.S. and Canada farmers use hormones; EU restricts import

Fear that hormones may affect child development, promote cancer

FAO and WHO say hormones found in beef are safe, less than found in normal human bodies

Antibiotics improve livestock weight gain, less disease

Indiscriminate use leads to development of resistant strains of bacteria—reduces antibiotic efficacy in humans

WHO recommended elimination of antibiotic use in livestock

Many European countries have complied; U.S. has not

Environmental Impacts

Air and water pollution

Use of fossil fuels and pesticides, animal wastes, fertilizers

Reduces biodiversity, harms fisheries, outbreaks of nuisance species

Replacement of family farms with agribusiness conglomerates

Cattle, hogs, poultry grown in feedlots and factories

Air and water pollution

Pesticide (toxic chemicals used to kill pests) resistance

Increasing use of pesticides, residues contaminate food, kills fish and other aquatic species, reduces beneficial soil organisms

Environmental Impacts

Land degradation

Reduction in the potential ability of the land to support crops/livestock

Soil erosion, compaction, salinization

Habitat fragmentation

Breakup of large areas of habitat into small, isolated patches

Clearing forests, grasslands, draining wetlands

Environmental InSight

Impacts of industrial agriculture

Increasing antibiotic resistance

Solutions to Agricultural Problems

Moving to sustainable agriculture

Agricultural methods that maintain soil productivity and a healthy ecological balance while having minimal long-term impacts

Also called alternative, or low-input agriculture

Combines modern with traditional techniques

Diversification of crops and livestock

Breeding of resistant varieties, to reduce use of chemicals

Water and energy conservation

Crop rotation, conservation tillage to preserve soil quality

Animal manure and leguminous crops to decrease the need for chemical fertilizers

Not a single program; adapted to local needs/conditions

Solutions to Agricultural Problems

Second green revolution

Away from high yield, towards long term-sustainability

Options and approaches

Organic agriculture

Integrated pest management

Reduction in intensive agricultural techniques

Increasing focus on long-term sustainability of the soil

Solutions to Agricultural Problems

EnviroDiscovery A New Weapon for Locust Swarms

Locusts periodically increase in number and swarm across agricultural lands, devastating crops and trees

In 1998, African farmers spayed massive quantities of pesticides, but there was great concern about the adverse ecological and health effects as well as the short-term costs ($300 million for 1998 swarm)

Non-chemical biological control was developed in response—fungal spores that target only locusts

“Green muscle” environmentally safe and very effective

In 2009, use of this biological control prevented major locust infestation in Tanzania

Solutions to Agricultural Problems

Genetic engineering

Manipulation of genes to produce a particular effect

E.g., taking a specific gene from one species and placing it into an unrelated species

Revolutionizing agriculture and medicine

Goals—to develop desirable characteristics in crops and livestock (= as traditional breeding)

Has the potential to produce

More nutritious food plants that contain all essential amino acids or that would be rich in vitamins

Resistant to viral diseases, drought, heat, cold, herbicides, salinity, insect pests, etc.

Solutions to Agricultural Problems

Here, a plasmid, a small circular molecule of DNA, introduces desirable genes from another organism into a plant cell

Solutions to Agricultural Problems

First GM crops were approved in the U.S. in early 1990s

Since 2000, GM production in developing countries has increased faster than in developed countries

In 2011, developing countries produced half of the world’s GM crop

GM production

More productive farm animals, fast growing hogs and fish

Utilized in the development and production of vaccines against disease organisms

Plants can be modified with genes that protect against insect pests and provide resistance to herbicides

Solutions to Agricultural Problems

Concerns about GM foods

In 1999 EU placed moratorium (since lifted) on approvals for all GM foods

EU refused to buy U.S. corn since 80+ percent of U.S. corn is GM

Spreading of GM genes to wild relatives of crop plants may harm natural ecosystems

Worry that consumers may develop allergies to new GM foods (even though routinely tested)

Scientific consensus is that health risks associated with consuming GM varieties is the same as those of consuming traditionally bred varieties

There are still unanswered questions about effects on environment

Controlling Agricultural Pests

Pest

Any organism that interferes in some way with human welfare or activity

Some pests compete with us for food, others spread disease

Pesticide

The agent used to reduce pest populations

Can be grouped by target organisms

Insecticides

Herbicides

Rodenticides

Fungicides

Controlling Agricultural Pests

Benefits of pesticides

Effectively control organisms that spread disease

Malaria, typhus

Protect crops from pests and pathogens

1/3 of crops are destroyed by pests

Monocultures (single species grown in large areas) amplify effect of pests

Monoculture crops generate very simple ecosystems, pests thrive, lots of food

Complex ecosystems with many species will have predators and parasites that compete with and control pest populations

Controlling Agricultural Pests

Problems with pesticides

Ideal pesticides

Narrow-spectrum—kills only the intended pest

Readily breaks down into safe materials

Does not move around in the environment

Most pesticides

Broad-spectrum—kills a variety of organisms, including beneficial ones

Do not degrade readily, or break down into other dangerous materials

Move around in the environment—enter water, air

Controlling Agricultural Pests

Problems with pesticides

Genetic resistance

In the 50 years of wide pesticide use, at least 520 species of insects and mites and at least 84 weed species have evolved genetic resistance to certain pesticides

Controlling Agricultural Pests

Problems with pesticides

Bioaccumulation

Biological magnification

Natural enemies (beneficial organisms) also die off from pesticide exposure

The resulting fewer natural controls for pests leads to increased pest populations and need for even larger pesticide use for their control

Movement of herbicides into water supplies increases human exposure and slightly elevates cancer risk

Controlling Agricultural Pests

Alternatives to pesticides

Biological controls

Uses naturally occurring disease organisms, parasites, or predators to control pests

Pheromones/hormones

Natural substance produced by animals to stimulate a response in other members of the species

Reproductive controls

Genetic controls

Quarantine

Irradiation

Controlling Agricultural Pests

Alternatives to pesticides

Integrated pest management (IPM)

Combination of pest control methods that if used in the right order and at the proper times, keeps the pest population small enough to prevent substantial economic loss

Controlling Agricultural Pests

Integrated pest management

Combines a variety of methods to control pests

Management, not eradication of pests

Farmers need to be educated on how to minimize pest effects

Important part of sustainable agriculture

Biological and genetic controls are used as much as possible

Conventional pesticides are used sparingly and only if other methods fail

Requires thorough knowledge of life cycles and feeding habits of pests

Few farmers are using IPM, but number is increasing

Applying pesticides is simple

IPM is more complicated, requires more knowledge

Controlling Agricultural Pests

Case Study

Organic agriculture

No usage of commercial inorganic fertilizers or pesticides

Organic Food Production Act of 1990

Specifies guidelines for organic production and labeling

Federal standards for organic certification went into effect in 2002

In 2008, 2 million hectares farmed organically in the U.S.

Rapid growth in organic agriculture in U.S. today

Case Study

Organic agriculture

Global and U.S. organic agriculture land use and growth