Food ResourcesLECTURE 9

Why Is Good Nutrition Important?

• Many people in less-developed countries have health problems from not getting enough food

• One in 8 people are not getting enough food (800 million people)

• Many people in more-developed countries suffer health problems from eating too much

• Greatest obstacles to providing enough food for everyone:

• Poverty, war, bad weather, and climate change

Chronic Hunger and MalnutritionTo maintain good health, people need:

• Macronutrients• Carbohydrates• Proteins• Fats

• Micronutrients• Vitamins

• Examples: A, B, C, and E• Minerals

• Examples: Iron, iodine, and calcium

Many People Suffer from Lasting Hunger and Malnutrition

Low-income, less-developed people suffer from:

• Chronic undernutrition:• Not enough food to meet basic energy needs

• Chronic malnutrition:• Not enough protein or other key nutrients (eat mostly low

on the food chain – wheat, rice, and corn)

• Famine: • Severe shortage of food

• Crop failures due to drought, flooding, or war

• Can cause mass starvation, many deaths, economic chaos, and social disruption

Essential Micronutrients• Two billion people deficient in one or more vitamins

and minerals

• Too little iron• Causes anemia (fatigue and increased chance of infection)

• Iodine • Essential for thyroid function• Chronic lack causes stunted growth, mental retardation,

and goiter• Irreversible brain damage

Health problems from eating too much food People live in food deserts where diet is heavy in cheap food filled with sugar and fats

• Overnutrition:• Excess body fat from too many calories and too little

exercise

• Similar health problems to those who are underfed:• Lower life expectancy

• Greater susceptibility to disease and illness

• Lower productivity and life quality

Poverty Is the Root Cause of Hunger and Malnutrition

• 28% of world’s people struggle to survive on USD $3.10 per day

• Poverty prevents daily access to nutritious food

• Other obstacles to food security:• War

• Corruption

• Bad weather

• Climate change

Poverty Is the Root Cause of Hunger and Malnutrition

• Generally, the number and percentage of people suffering from chronic hunger has declined since 1992

• Some continents, like Africa, still suffering greatly

Food Production has Increased Dramatically

• Three systems produce most of our food:• Croplands produce grains

• Primarily rice, wheat, and corn• At least half the world’s people survive primarily by eating

three grain crops–rice, wheat, and corn–because they cannot afford meat

• Rangelands, pastures, and feedlots produce meat and meat products

• Fisheries and aquaculture provide fish products

• Important technological advances have increased food production:• Irrigation, synthetic fertilizers, and pesticides

Industrialized Agriculture• Industrialized agriculture (high input):

• Heavy equipment• Large amounts of financial capital, fossil fuels, water, inorganic

fertilizers, and pesticides• Single crop• Major goal: Steadily increase crop yield• Produces 80% of world’s food

• Plantation agriculture–cash crops (form of industrialized agriculture)

• Primarily in less-developed countries• Bananas, coffee, soybeans, sugarcane, palm oil and vegetables• Mostly for export to other countries

Traditional Agriculture • Traditional agriculture provides about 20% of the world’s agriculture

• Traditional subsistence agriculture:• Human labor and draft animals for family food• Little leftover or for sale

• Traditional intensive agriculture:• Higher yields through increased labor, animal manure, and

water• May have some leftover for sale

• Polyculture:• Several crops grown on same farm• Benefits over monoculture

Polyculture

• One type of polyculture–slash and burn

• Burning and clearing small plots of land, growing multiple types of crops until soil is depleted of nutrients, and then shifting to other plots to start the process again

Increasing Influence of Organic Agriculture • Crops grown without synthetic pesticides or fertilizers:

• No genetically engineered seed varieties

• Animals must be raised with 100% organic feed without antibiotics or growth hormones

• More labor-intensive than conventionally produced food:

• Costs more

Impacts of Green Revolution • Farmers have two ways to get more food–farming more land or getting higher yields

• Green Revolution–using high input industrialized agriculture to increase crop yields (1950-1970):

• Develop and plant monocultures of high-yield key crops• Rice, wheat, and corn

• Use large amounts of fertilizers, pesticides, and water• Use multiple cropping

• Second Green Revolution (1967)• Fast growing varieties of rice and wheat were introduced to India, China, and Brazil

• World grain production quadrupled between 1950 and 2018

• https://www.youtube.com/watch?v=ymMajMVCFhk

Crossbreeding and Genetic Engineering• Scientists have used crossbreeding to produce new varieties of food

• First gene revolution:• Crossbreeding through artificial selection

• Slow process (15 years or more to create a new product)• Amazing results (ears of corn used to be size of your finger)

• Genetic engineering–second gene revolution:• Alter an organism’s DNA• Genetically modified organisms (GMOs)–transgenic organisms• Altering organisms to produce better products

Growing Meat Consumption

• Meat production increased more than six folds between 1950 and 2018:

• Pork, poultry, and beef top products

• Increased demand for grain• Greater reliance on grain imports

• China

• About half of the world’s meat raised on rangeland:• Half in factory farm system

Fish and Shellfish Production • Fishery:

• World’s third major producing food system

• Concentration of a particular species suitable for commercial harvesting

• 29% are overfished

• 61% harvested at full capacity

Aquaculture

• Aquaculture:• Fish farming

• Amount of fish and shellfish produced globally through aquaculture increased 21% from 2000 to 2016

• Wild catch leveled off and declined

• Farming of meat-eating species growing rapidly• Fed fish meal or fish oil produced from other fish and

their waste

Energy Inputs in Industrialized Food Production • Mostly use nonrenewable energy for food production:

• Oil and natural gas

• Ten units of fossil fuel energy used for every unit of food energy in the U.S.:• Amount of energy per calorie used to produce crops in the U.S. has declined 50%

since the 1970s• Less energy required to produce nitrogen fertilizer

• Rising use of conservation tillage (reduces harmful effects of plowing)

Environmental Effects of Industrialized Food Production• Factors that may limit future food production:

• Soil erosion and degradation

• Desertification

• Irrigation water shortages

• Air and water pollution

• Climate change

• Loss of biodiversity

Producing Food Has Major Environmental Impacts• Industrialized agriculture has harmful environmental impacts:

• Uses about 70% of freshwater removed from aquifers and surface waters worldwide

• Emits 25% of the world’s greenhouse gas emissions

• Produces 60% of all water pollution

• Some say industrialized agriculture is unsustainable

Topsoil Erosion• Topsoil has several necessary nutrients and provides vital ecosystem

services.

• Need healthy soils for agriculture

• Soil erosion: • Movement of soil by wind and water• Natural causes• Human causes (agriculture)

• Three major harmful effects of soil erosion:• Loss of soil fertility• Water pollution• Release of carbon stored in the soil as CO2

The Phosphate Crisis• Phosphate is needed for fertilizer

• Availability from mines is limited

• Potential solutions• Water crops with phosphate-rich wastewater• Reduce soil erosion• Applying fertilizer so that less of it is lost

Desertification • Desertification:

• Productive potential of topsoil falls by 10% or more

• Caused by prolonged drought and human activities

• Human agriculture accelerates desertification

• Dust bowl:• Severe wind erosion of topsoil

Excessive Irrigation, Soil Salinization and Waterlogging

• Irrigation has downsides: Most irrigated water is a dilute solution of various salts

• Water not absorbed leaves behind a crust of mineral salts in the topsoil

• Soil salinization:• Gradual accumulation of salts in the soil from irrigation water• Lowers crop yields and eventually kills plants• Affects 10% of world croplands

• Waterlogging:• Irrigation water gradually raises water table• Can deprive plants of oxygen• Affects 10% of world croplands

Pollution and Climate Change• Eroded topsoil flows into streams, lakes, and wetlands:

• Aquatic organisms ingest pesticide residues

• Smothers fish and shellfish

• Farmers contribute to pollution through over fertilizing:• Use of fertilizers has grown forty-five-fold since 1940

• Causes eutrophication

• Nitrates contaminate groundwater used for drinking

Pollution and Climate Change• Agricultural activities can also cause air pollution:

• Comprise more than 25% of human generated CO2 emissions

• Warms atmosphere and contributes to climate change which can affect crops

Food production and biodiversity loss

• Biodiversity threatened when forest and grasslands replaced with croplands

• Example: Brazil–areas of the Amazon basin tropical forest are being lost (burned or cleared for cattle)

• Loss of agrobiodiversity:• Genetic variety of animal and plant species used on farms to

produce food• 75% lost since 1900• For example, India once planted 30,000 varieties of rice–now more

than 75% of its rice production comes in only ten varieties

Controversy over Genetically Engineered Foods• Genetic engineering could help improve food security

• Little is known about long-term health effects:

• Bt (bacillus thuringiensis) produces a chemical toxin that could trigger inflammatory response

• Bt toxin can make leaves more resistant to damage from insects but could threaten human health

• Potential environmental effects of genetically modified populations in the wild:• Threatens biodiversity and can cause a decline pollinators, which affect plants and animals• Creating hybrids with natural organisms reduces the natural genetic biodiversity of wild strains

Industrialized Meat Production Harms the Environment• Pros:

• Increased meat supply

• Reduced overgrazing

• Kept food prices down

Industrialized Meat Production Harms the Environment• Cons:

• Uses large amounts of water to irrigate grain crops fed to animals• According to Waterfootprint.org, producing a quarter-pound hamburger requires 1,752

liters (63 gallons) of water

• Livestock wastes pollute waterways and aquatic ecosystems

• Uses large amounts of energy (mostly from oil)

• As part of their digestion process, cattle and dairy cows release methane, a greenhouse gas with about 25 times the warming potential of CO2 per molecule

• Antibiotic resistance

Environmental Impact of Aquaculture • Aquaculture produces 47% of the world’s seafood and is

growing rapidly

• By 2030, aquaculture will produce 62% of all seafood

• Several environmental problems:• Fish are caught to use as feed on fish farms

• Contributes to depletion of wild fish• Environmental toxins

• Pesticides and antibiotics on fish farms a source of pollution• Can destroy or degrade mangrove forests (systems are cleared

for aquaculture)

How Can We Protect Crops from Pests More Sustainably?• Pesticide use can be sharply cut without decreasing crop yields by using a mix

of:• Cultivation techniques

• Biological pest controls

• Small amounts of selected chemical pesticides as a last resort (integrated pest management)

Nature Helps Control Many Pests • Pests: Any species that interferes with human welfare

• Worldwide, only about 100 species of plants (weeds), animals (mostly insects), fungi, and microbes cause most of the damage to the crops we grow.

• Natural enemies control pest populations:• Predators, parasites, and disease organisms • In natural ecosystems • Free ecosystem service

• Biologists estimate that the world’s 46,700 known species of spiders kill far more crop-eating insects every year than humans kill with insecticides.

Synthetic Pesticides

• Synthetic pesticides: • Chemicals used to kill or control pests• Include insecticides, herbicides, fungicides, and

rodenticides (rats and mouse)• For nearly 225 million years, plants have been

producing chemicals to ward off, deceive, or poison the insects and herbivores that feed on them.

• Biopesticides (learning from nature):• Produced by plants to ward off insects and

herbivores

Synthetic Pesticides• First-generation pesticides:

• Borrowed from plants

• Second-generation pesticides: DDT• Lab produced

• Broad-spectrum agents:• Can be toxic to beneficial species

• Narrow-spectrum agents

• Persistence varies (length of time they remain deadly in the environment)

Advantages of Synthetic Pesticides• Human lives saved from malaria (DDT)

• Increase food supplies and reduce food losses due to pests

• Help control erosion and build soil fertility:• By avoiding plowing because farmers apply herbicide instead of weeding the soil by

plowing

• Help farmers reduce costs (higher crop yields)

• Newer pest control methods are safer, faster, and more effective

Disadvantages of Synthetic Pesticides• Accelerate development of genetic resistance in pests

• Expensive for farmers because of genetic resistance

• Some insecticides kill natural predators or parasites that help control pests

• Cause environmental pollution

• Some harm wildlife

• Some are human health hazards

Alternatives to Synthetic Pesticides

• Pesticides are not necessary to feed the world, they are not tested rigorously for safety, and there are alternatives.

• Scientists urge to reduce the use of pesticides by using:• Biological controls

• Natural predators and parasites• Pheromones and hormones

• Ecological controls• Use plant diversity to provide habitats for predators of pest species

• Cultivation controls• Vary crops and adjust planting times to starve pests

Integrated Pest Management

• Integrated pest management (IPM): • Program in which each crop and its pests are evaluated as parts of an

ecosystem• When farmers using IPM detect an economically damaging level of pests

in any field, they start with biological methods (natural predators, parasites, and disease organisms) and cultivation controls (such as altering planting times and using large machines to vacuum up harmful pests)

• Can reduce pesticide use by 50%• Goal: Minimal use of synthetic pesticides

Integrated Pest Management • Disadvantages

• Requires expert knowledge

• Methods applied in one area might not apply in another

• Initial costs higher

How Can We Produce Food More Sustainably?• We can produce food more sustainably by:

• Using resources more efficiently

• Sharply decreasing the harmful environmental effects of industrialized food production

• Eliminating government subsidies that promote such harmful impacts

Conserve Topsoil

• Soil conservation: reducing topsoil erosion and restoring fertility (keeping land covered with vegetation):

• Terracing• Contour planting• Strip cropping with cover crop• Alley cropping, agroforestry• Windbreaks or shelterbelts• Conservation-tillage farming

• Identify erosion hotspots

Restore Soil Fertility• Another way to protect soil is to restore some of the lost plant nutrients that have been washed,

blown, or leached out of topsoil.

• Organic fertilizer from plant and animal materials:• Animal manure• Green manure• Compost

• Manufactured inorganic fertilizer: • Nitrogen, phosphorus, and potassium

• Biochar: A form of charcoal made from woody materials

• Crop rotation avoids the depletion of nutrients

Reduce Soil Salinization and Desertification • Soil salinization:

• Costly solutions

• Desertification (can’t control the timing and location of droughts):• Reduce

• Population growth• Overgrazing• Deforestation• Destructive forms of planting, irrigation, and mining

• Plant trees that anchor topsoil

Reducing the Environmental Effects of Meat Production

• Shift from less efficient forms of animal protein to more efficient:• Pork and poultry are more efficient than beef

• Reduce or eliminate meat intake

• Insects are another source of protein

• Some countries are finding alternatives to grain-based production:• India’s dairy industry uses crop residues such as rice straw and corn

stalks• Saves energy and reduces greenhouse gas emissions

Shifting to More Sustainable Aquaculture • Aquaculture Stewardship Council:

• Developed sustainability standards• Certified <5% of world’s aquaculture operations

• Open-ocean aquaculture (currents wash away fish wastes)

• Inland facilities with recirculating aquaculture• Water is continually recycled

• Polyaquaculture• Raise fish or shrimp with algae, seaweed, and shellfish (waste of one species feeds

another)

Expand Organic Agriculture• Some benefits of organic farming:

• Builds soil organic matter• Reduces erosion and water pollution• Uses less fossil fuel energy• Cuts greenhouse gas emissions• Match conventional yields• More weed-tolerant• Crops compare favorably in years of drought• More profitable

How Can We Improve Food Security?• Government policies have controlled food prices and provided subsidies:

• New Zealand and Brazil have ended farm subsidies successfully

• Government and private programs that target poverty can improve food security:

• Low interest loans

• Immunizations and vitamins for children

Grow and Buy More Food Locally and Cut Food Waste

• Community supported agriculture:• People buy a share of a local farmer’s crops

• Receive box of produce on a regular basis during growing season

• Supports local economies and farm families

• Much food waste occurs in restaurants, homes, and supermarkets:

• 30–40% of food supply thrown away each year