Food and Agriculture Chapter 15 Environmental Science Feeding

Food and Agriculture Chapter 15 Environmental Science

Feeding the World Agriculture must provide most of the world’s population with food to survive. n Food shortages can occur n n n Famine Uses of food in the human body n n Energy Building and maintaining body tissues

Humans and Nutrition n Calorie (Cal) n n n Amount of energy available in food Equals 1, 000 calories Nutrients that provide calories n n Carbohydrates Lipids Proteins Malnutrition n Condition when humans don’t consume enough calories or good variety of food (ex – eating only corn or rice) n Amino acid deficiency

Sources of Nutrition n Diet n n Type and amount of food that a person eats Healthy diet contains the right amounts of: n n Minerals Nutrients Vitamins Diets vary by region n More developed countries eat more food

The Ecology of Food n Food Efficiency n n n Measure of quantity of food produced on a given area of land It takes more energy and land to produce an animal than a plant Therefore, it is more efficient to raise plants on a given area of land However, meat from animals has more nutrients Yield n Amount of food that can be produced in a given area

World Food Problems n Unequal Distribution n n If all food was divided equally worldwide, each person would not have enough for a healthy diet Causes n n n Poverty Wars Political strife

World Food Problems, cont. n Droughts n n Long period of time with below average rainfall Crops without irrigation will have low yields May cause a famine Effects of a drought can be felt for years n n No seeds to grow plants the following year People survive through one year of drought n Multiple years of drought can cause severe problems

The Green Revolution n Changes in growing crops (more produced) n n n Use of new crop varieties Applying modern agricultural techniques Negative effects n n n Use of more water, fertilizer, pesticides Equipment might degrade the soil Some overuse of pesticides and fertilizers

Assignment Page 383 n Section 1 Review n #1 -5 n

Crops and Soil n Arable land n n Land that can be used to grow crops Steps to farming arable land 1. Plowing - Mixes nutrients, loosens soil, uproots weeds 2. Fertilization - Adds nutrients to the soil (ex - manure) 3. 4. Irrigation Pest Control - Weeds are removed by hand or machine

Fertile Soil Topsoil (rich in organic matter) n How soil forms n n Rock is broken down into smaller fragments n n Wind, Water Chemical weathering § Minerals in rock react with water to form new materials n n Fungi and bacteria (Decompose dead plants) Earthworms and insects n n Break up soil to allow plant roots to grow Fertile soil will have many earthworms in it

Soil Erosion About ½ of US topsoil has been lost to erosion in past 200 years n All farming methods increase erosion n n Plows loosen the soil Plants with roots are removed Soil is now exposed to wind and water Land Degradation n Human activities or natural processes damage the land

Soil Conservation n Desertification n When land that is arid becomes more desert-like Caused by human activity and climate changes Reducing erosion n Contour plowing (Plow across slope, not up & down) Leaving strips of vegetation across the hillside No-till farming n n No plowing before planting the seeds – saves time Not usable for all crops and could have lower yields

Enriching the Soil Traditional fertilizers (manure, leaves) n Fertilizers today n n n N, P, & K Helps yields to be twice as much as before Can pollute the waterways if runoff carries it Compost n Partly decomposed organic matter § Manure, yard waste, crop waste n Saves costly landfill space, easy to use

Salinization Accumulation of salts in the soil n Problem in places with low rainfall and naturally salty soil (CA and AZ) n Irrigation water has a high level of salt n n After the water evaporates, the salt is left Plants won’t grow if soil has too much salt n Lined irrigation canals can help prevent this n

Assignment Section 2 Mid – Section Review n Page 388 n # 2 -4, 6 n

Pest Control n Pest problem n n Kills 33% of crops worldwide Pest n n Any organism that is not wanted or occurs in a large population which causes economic damage Pest can be a plant, insect, fungi or microorganism

Pesticides n Chemicals used to kill insects, weeds and other crop pests n n Allows farmers to control pest populations in their crops Can harm beneficial plants and insects, wildlife and sometimes people

Pesticide Resistance The ability to survive exposure to a particular pesticide n This happens after years of applying the same pesticide to a given area n How to correct this problem n n Use different brands of pesticides each year

Human Health Concerns n Pesticides are meant to kill n n Can increase the occurrence of cancer Can make a person very ill People who live near factories are at risk of accidental chemical leaks Always follow safety guidelines to protect yourself when working with chemicals

Pollution and Persistence n n Persistent chemicals will cause pollution n n When a pesticide does not break down easily or quickly in the environment They accumulate in soil and water Most persistent chemicals are now banned n Example - DDT

Pest Management n Biological Pest Control n n Use of living organisms to control pests Types n Pathogens § Organisms that cause disease § Example – Bt kills caterpillars that become moths, etc. n Plant Defenses § Genetically bred to withstand pests n Chemicals from plants (biodegradable)

Biological Pest Controls, cont. n Disrupting insect breeding n Growth regulators n n Chemicals that interfere with pest life cycles Pheromones n n Chemicals produced by one organism that affects another Female moths release pheromone that attracts males Farmers confuse males by spraying plants This disrupts the moths’ breeding patterns

Integrated Pest Management Method of controlling pests on crops n Every crop has its own management plan n n Farming methods Biological pest control Chemical pest control Plan is set into place once the pest has been identified

IPM, cont. n Steps to IPM 1. Biological methods - Natural predators Pathogens Parasites 2. Cultivation controls - Vacuuming pest off the plants 3. Chemical control - small amounts of insecticides are used

Engineering a Better Crop n Genetic engineering n n n Genetic material in a living cell is modified for medical or industrial use Genes are isolated in one organism Genes from another organism are then added This results in genetically modified plants We eat a large amount of food that has been genetically engineered

Sustainable Agriculture Farming that conserves natural resources n Helps keep the land productive indefinitely n AKA – low-input farming n Uses less water, energy, pesticides, fertilizers n

Assignment Section 2 Review n Page 394 n #1 -6 n

Animals and Agriculture n Food from animals has been the basis for life for thousands of years n n Most of this food coming from domesticated animals (cattle, sheep, goats) Fish problem - overharvesting n Ways to control overharvesting § No-fishing zones (Allows the fish time to reproduce) § Aquaculture § Raising of aquatic organism for human use § China is the world leader in aquaculture production

Aquaculture n Methods n Fish farm n n n Ranch n n Individual ponds that have fish at different life stages Clean water circulates through constantly Fish are raised to a certain age, then released Common types of fish produced n n Catfish, salmon, crayfish, rainbow trout Other water organisms such as oysters

Problems with Aquaculture n Creates a large amount of wastes n n Requires a large amount of water n n Can cause pollution Can deplete local water sources Sensitive wetlands can be damaged n When aquaculture operations are located here

Livestock Domesticated animals that are raised to be used on a farm or ranch or to be sold for profit n Serve many functions n n n Provide food Provide other products like leather, wool, eggs Pull carts and plows Provide manure as fertilizers or as fuel

Ruminants n Cud-chewing animals that have four sections to their stomach n n Cud n n Food that is regurgitated and chewed again Microorganisms in their stomach n n Cattle, sheep, goats Allows them to digest plant material Animals used for meat and milk

Poultry n Domesticated birds raised for meat & eggs n n n Chicken Turkeys Ducks Geese Poultry is also used for their droppings n Excellent fertilizer sources

Assignment Section 3 Review n Page 399 n #1 -4 n

Chapter 15 Review Pages 401 -403 n #6 -27, 29, 35 -38 n