APES Ch 13

Food, Soil Conservation and Pest Management

Food Security and Nutrition 1 in 6 people in developing countries does not get

enough food (most likely due to poverty)

Food security:

Most developing nations can not provide food security to all their people b/c they cant produce enough food or they can’t afford to import.

Also depends on reducing harmful environmental effects of agriculture (erosion, aquifer depletion).

Food Security and Nutrition Chronic hunger:

Malnutrition:

UN Food and Agriculture Organization (FAO) goal is to reduce the # of hungry and malnourished to 400 million by 2015 (as of 2005 there were 852 million)

FAO estimated that 6 million children died each year due to lack of essential food.

Food Security and Nutrition Famine:

Can lead to mass migrations Usually caused by crop failure due to drought,

flood, war or other catastrophic events. Overnutrition:

Can cause some of the same problems as under-nutrition (lower life expectancy, diseases, lower life quality)

Food Production 3 systems that supply most food:

Croplands – 77% Rangelands – 16% Oceanic fisheries and aquaculture – 7%

All 3 systems have increased since 1960 due to better technology and other advances (fertilizers, pesticides, irrigation).

May not be able to produce enough food by 2050 for the possible 8.5 billion people.

Environmental degradation, pollution, lack of water, overgrazing, overfishing, rising temps., increasing fuel costs

Food Production Only 14 plants and 9 terrestrial animal

species supply an estimated 90% of worlds food. 3 types of grain (wheat, rice and corn) provide

more than 50% Many people can’t afford meats, milk and cheese

products. Fish and shellfish make up only 7%

Food Production Industrialized agriculture (high input):

80% of worlds food supply is produced this way Plantation agriculture:

Cash crops (bananas, soybeans, sugarcane, cocoa, peanuts and coffee

Must clear tropical rain forests to plant Livestock

Most are in feedlots Use lots of energy and water and produces lots of animal

waste and water pollution

Fig. 13-6, p. 276

Natural Capital

Croplands

• Help maintain water flow and soil infiltration • Food crops

• Provide partial erosion protection• Fiber crops

• Can build soil organic matter

• Crop genetic resources• Store atmospheric carbon

• Provide wildlife habitat for some species • Jobs

Ecological Services

Economic Services

Food Production Traditional agriculture (low input)

Traditional subsistence agriculture:

Traditional intensive agriculture:

Interplanting:

Reduces chance of losing all of the years food supply Polyvarietal cultivation: Intercropping: Agroforestry (alley cropping): Polyculture:

Keeps soil covered, less fertilizer and water use, less pesticides.

Soil Erosion and Degradation Topsoil:

Naturally renewable but very slow (several 100 yrs to make 1 inch)

Soil erosion:

Increases when vegetation is removed Sheet erosion: Rill erosion: Gully erosion: Major effects of erosion

Loss of soil fertility Water pollution due to sedimentation runoff

Fig. 13-12, p. 280

Causes Consequences Overgrazing Worsening

droughtDeforestationFamineErosionEconomic losses

SalinizationLower living standardsSoil compaction

Natural climate change

Environmental refugees

Soil Erosion and Degradation

Desertification:

1/3 of the worlds land and 70% of all dryland are suffering from desertification.

Fig. 13-13, p. 281

EvaporationTranspiration

EvaporationEvaporation

Waterlogging

Salinization: Waterlogging:1. Irrigation water contains small amounts of dissolved salts

2. Evaporation and transpiration leave salts behind.

3. Salt builds up in soil.

1. Precipitation and irrigation water percolate downward.

2. Water table rises.

Less permeable clay layer

Fig. 13-15, p. 281

CleanupPrevention

Soil Salinization

Solutions

Reduce irrigation

Switch to salt-tolerant crops (such as barley, cotton, sugarbeet)

Flush soil (expensive and wastes water)

Stop growing crops for 2–5 years

Install underground drainage systems (expensive)

Sustainable Agriculture Through Soil Conservation Soil conservation:

Eliminating plowing and breaking up and tilling is key to reduce soil erosion.

Conservation-tillage farming: Terracing: Contour farming: Strip cropping: Wind breaks: Use cover crops

Sustainable Agriculture Through Soil Conservation

Organic fertilizer:

Animal manure: Green manure: Compost:

Commercial inorganic fertilizer:

Contain nitrogen, phosphorus, and potassium Crop rotation:

Also helps reduce erosion

The Green Revolution and its Environmental Impact Green Revolution:

Plant monoculture plants Use large amounts of fertilizer, pesticides and water for

higher yield Increase the # of crops grown per on plot of land

through multiple cropping 1st Green Revolution took place between 1950-

1970 in developed countries 2nd Green Revolution has been taking place since

1967 in developing countries mostly in tropical areas.

The Green Revolution and its Environmental Impact Pros

Has produced more food for growing population Many countries are now self sufficient with food Use less land for larger yield

Cons More fertilizer, pesticides and water To expensive for subsistence farmers If expanded- not enough workers (more people moving

to cities for jobs) More irrigation which can lead to more salinization

The Green Revolution and its Environmental Impact More land can be planted with crops but

significant expansion of cropland is unlikely over the next few decades for economic and ecological reasons

Loss of agrobiodiversity – the worlds genetic variety of animals and plants used to provide food Ex: India use to plant 30,000 different types of

rice, now only 10 types are used.

The Green Revolution and its Environmental Impact Modern agriculture violates the 4

Principles of Sustainability Depends heavily on nonrenewable fossil fuels Too little recycling of crop and animal wastes Accelerates soil erosion Does not preserve agrobiodiveristy Disrupts natural species interactions that help

control population sizes and pests.

Fig. 13-18, p. 285

Biodiversity Loss Soil Water Air Pollution Human Health Loss and degradation of grasslands, forests, and wetlands

Erosion Water waste Greenhouse gas emissions from fossil fuel use

Nitrates in drinking water

Loss of fertility Aquifer depletion

Pesticide residues in drinking water, food, and air

Salinization Increased runoff and flooding from cleared land

Other air pollutants from fossil fuel use

Fish kills from pesticide runoff

Waterlogging

Sediment pollution from erosion Greenhouse gas

emissions of nitrous oxide from use of inorganic fertilizers

Contamination of drinking and swimming water with disease organisms from livestock wastes

Desertification

Killing wild predators to protect livestock

Fish kills from pesticide runoff

Surface and groundwater pollution from pesticides and fertilizers Belching of the

greenhouse gas methane by cattle

Loss of genetic diversity of wild crop strains replaced by monoculture strains

Bacterial contamination of meat

Overfertilization of lakes and rivers from runoff of fertilizers, livestock wastes, and food processing wastes

Pollution from pesticide sprays

The Gene Revolution For years the use of crossbreeding through

artificial selection to develop genetically improved varieties of crop strains has been used.

Now genetic engineering is being used (takes a gene of 1 species and inserts it into the DNA of another species) Takes ½ the time and cost less then

crossbreeding Ex: potatoes resist disease because they contain a

certain chicken gene.

The Gene Revolution Nontraditional foods could help provide

essential nutrients and lower the need for some crops. Winged bean has many edible parts and

requires little fertilize. Quinoa plant is called the worlds most

nutritious plant and can resist frost and droughts and can grow in saline soils.

Insects are a great source of protein and are easy to “farm”

Fig. 13-19, p. 287

Projected DisadvantagesIrreversible and unpredictable genetic and ecological effects

Need less fertilizer

Need less water

More resistant to insects, disease, frost, and drought

Harmful toxins in food from possible plant cell mutations

Grow faster New allergens in food

Can grow in slightly salty soils

Lower nutrition

Less spoilage

Increased development of pesticide-resistant insects and plant diseases

Need less pesticidesCan create herbicide-resistant weeds

Better flavor

Tolerate higher levels of herbicides

Can harm beneficial insects

Lower genetic diversityHigher yields

Trade-Offs

Genetically Modified Crops and Foods

Projected Advantages

Producing More Meat Between 1950-2005 meat production increased

more then 5 fold and is likely to double again by 2050 as more people become affluent.

2 systems for raising livestock Graze on grass Feedlots- raise in densely packed areas by feeding them

grain and/or fish meal. Animals given antibiotics and steroids Accounts for 43% of worlds beef, 50% of pork and 68% of

eggs, and 75% of poultry production. Solutions: people can eat more poultry and fish rather then

beef, establish more humane ways to raise livestock in feedlots.

Fig. 13-21, p. 289

Trade-Offs

Animal Feedlots

Advantages Disadvantages

Increased meat production

Need large inputs of grain, fish meal, water, and fossil fuelsHigher profits

Concentrate animal wastes that can pollute water

Less land use

Reduced overgrazing

Reduced soil erosion

Antibiotics can increase genetic resistance to microbes in humans

Help protect biodiversity

Producing More Meat Catching and raising more fish and

shellfish. Fisheries:

3rd major food producing system. 2/3 comes from oceans, lakes, rivers and ponds 1/3 comes from aquaculture

Scientists project a decline in global fish catch due to overfishing, coastal water pollution and wetland destruction

Producing More Meat 125 out of 128 depleted fish stocks could recover

with careful management. Ecolabels help shoppers identify wild fish that

have been caught by more sustainable fishing practices. Walmart said that within 5 yrs it would sell only fish

certified by the Marine Stewardship Council) Govt's subsides given to the fishing industry are a

major cause of overfishing. Subsides $ should be used to buy out some fishing boats

and retrain their crew for other occupations

Producing More Meat Aquaculture:

Fishing farms:

Fishing ranches:

Mainly carp in China and India, catfish in US, tilapia and shellfish in other countries

Fig. 13-24, p. 292

Trade-Offs

Aquaculture

Advantages Disadvantages

High efficiency Needs large inputs of land, feed, and water

High yield in small volume of water

Large waste output

Destroys mangrove forests and estuaries

Can reduce overharvesting of conventional fisheries Uses grain to feed

some species

Low fuel use Dense populations vulnerable to disease

Tanks too contaminated to use after about 5 years

High profits

Profits not tied to price of oil

Fig. 13-25, p. 293

Solutions

More Sustainable Aquaculture

• Use less fishmeal feed to reduce depletion of other fish

• Improve management of aquaculture wastes

• Reduce escape of aquaculture species into the wild

• Restrict location of fish farms to reduce loss of mangrove forests and estuaries

• Farm some aquaculture species in deeply submerged cages to protect them from wave action and predators and allow dilution of wastes into the ocean

• Certify sustainable forms of aquaculture

Solutions: Moving Toward Global Food Security People in urban areas could save money

by growing more of their own food. We can waste less food (70% of food is

wasted through spoilage, inefficient processing and plate waste). US households throw away food worth as much

as $43 million/yr – twice the $24 million it would take to eliminate global hunger

Solutions: Moving Toward Global Food Security

We can increase global food security by – Slow pop growth Reduce poverty Reduce soil erosion Halt desertification Eliminate overgrazing Slow removal of groundwater Protect cropland from development Reduce rate of global warming

Protecting Food Resources: Pest Control Pest:

Only 100 species cause 90% of the damage to crops

In nature natural enemies control 98% of the potential pests species

Pesticides:

Protecting Food Resources: Pest Control 2 generations of pest control

1st generation (copy nature): before 1930s many pesticides were derived from organisms (mostly plants). They were natural defenses.

2nd generation: the development of pesticides in labs. Started in 1939 when DDT was discovered. Some lab made pesticides last in environment for years and can biologically magnified in food chains.

¾ of pesticides is used for crops, ¼ is used for homes, gardens, and golf courses.

Federal Insecticide, Fungicide, Rotenticide Act (FIFRA) is suppose to assess the health risks of the active ingredients in pesticide products.

Fig. 13-25, p. 293

Solutions

More Sustainable Aquaculture

• Use less fishmeal feed to reduce depletion of other fish

• Improve management of aquaculture wastes

• Reduce escape of aquaculture species into the wild

• Restrict location of fish farms to reduce loss of mangrove forests and estuaries

• Farm some aquaculture species in deeply submerged cages to protect them from wave action and predators and allow dilution of wastes into the ocean

• Certify sustainable forms of aquaculture

Protecting Food Resources: Pest Control Other ways to control pests:

Fool pest Provide homes for pest enemies Implant genetic resistance Bring in natural enemies Use insect perfumes Bring in hormones Scald pests

Fig. 13-33, p. 302

Solutions

Sustainable Organic Agriculture

More Less

High-yield polyculture

Soil erosion

Soil salinizationOrganic fertilizers

Aquifer depletionBiological pest control Overgrazing

Integrated pest management

Overfishing

Loss of biodiversity

Efficient irrigation Loss of prime

croplandPerennial crops

Crop rotationFood waste

Water-efficient crops

Subsidies for unsustainable farming and fishing

Soil conservation

Subsidies for sustainable farming and fishing

Population growth

Poverty