Food and Agriculture Chapter15

Feeding the World Do you think there is enough food available in the world to feed everyone? In your opinion, how many people in the world do not get enough to eat each day?

Feeding the World Famine- widespread starvation caused by a shortage of food. In 1985, lack of rain, loss of soil, and war caused crops to fail in Ethiopia.

Humans and Nutrition Food is a source of energy and contains materials for maintaining body tissues. Calories- the amount of energy in food.

Humans and Nutrition Malnutrition occurs when people do not consume enough calories or not a sufficient variety of foods. Many forms of malnutrition. Example: Protein-energy malnutrition.

Sources of Nutrition The food produced in the greatest amounts world wide is grains. In most parts of the world, people eat foods high in carbohydrates. Grains are high in carbohydrates.

Diets Around the World People in developed countries tend to eat more food and larger portions of proteins and fats than people eat in developing countries.

The Ecology of Food Feeding everyone while maintaining natural ecosystems is difficult to accomplish. Different types of agriculture have different environmental impacts and levels of efficiency.

Food Efficiency Efficiency is measured by the amount of food produced with the least amount of resources used. It takes more energy, water and land to produce a calorie of food from an animal then it does to produce a calorie from a plant.

Food Efficiency Since it is less expensive to grow grain than raise animals, most of the diets around the world are based largely on plants. Meat from animals, however, provide us with more nutrients per gram than plants do.

World Food Problems Farmers produces enough grain food for 10 billion people. (vegetarian diet). However, many of us consume 1/3rd of our calories from animals instead of grain.

Subsistence farmers Subsistence farmers work tiny plots of land to produce enough food for their family and sell what is left to local people. Lack access to water for irrigation, which would increase their yield.

Poverty Malnutrition is the result of poverty. Poverty is defined as an income of less than a dollar a day. The worlds hungry mainly live in Asia, Africa, and parts of South America.

Poverty The number of people in poverty has declined by nearly a ½ billion since 1980. Reason- Asia, especially in China and India due to urbanization.

The Green Revolution A period of time when wheat production doubled in production. Resulted from new varieties of grain These new grains produced large yields Reduced the price of food and improved nutrition

The Green Revolution Drawbacks: Subsistence farmers cannot afford the new crops. It requires more water and fertilizers. Loss of biodiversity More pesticide use

Arable Land Land that can be used to grow crops Urban areas occupy 3% of the Earth’s land surface, often expanding into arable land. Only ~10% of the Earth’s surface

Traditional Farming: 4 basic processes Plowing Fertilization Irrigation Pest Control

Plowing Plowing helps grow crops by Mixing soil nutrients Loosening soil particles Uprooting weeds

Traditional Plowing

Fertilizers Fertilizers, such as manure, are used to enrich the soil so that plants grow strong and healthy. Organic Manure Tumbling Machine Manure Runoff

Irrigation Traditionally, fields were irrigated by water flowing through ditches.

Modern Farming In industrialized countries, farming processes are now carried out using modern agricultural machines. Machinery powered by fossil fuels is now used to plow the soil and harvest crops.

Modern Fertilizer Synthetic chemical fertilizers are now used instead of manure and plant wastes to fertilize soil.

Fertile Soil: The Living Earth Fertile Soil- soil that can support the growth of healthy plants

Topsoil The surface layer of soil Characteristics: Usually richer in organic matter The layer in which plant roots grow Is composed of Living organisms Rock particles Water Air Organic matter: decomposing organisms

Topsoil

Chemical Weathering Soil forms when rock is broken down into small fragments by wind, water, and chemical weathering. Chemical weathering happens when the minerals in the rock react chemically with substances, such as water, to form new materials.

Erosion The movement of rock and soil by wind and water Without topsoil, crops cannot be grown. Topsoil pours into the ocean at the mouth of the Mississippi River, here seen from space. Topsoil eroding from North American farmland.

Erosion Farming methods increase the rate of soil erosion: Plowing loosens the soil and removes plants that hold the soil in place Water runoff from irrigation systems carries soil with it

Erosion happens easily where the soil surface is bare. Water runs off instead of soaking into soils, causing flooding and erosion downstream. Erosion can remove huge amounts of soil.

Land Degradation Occurs when human activity or natural processes damage the land so that it can no longer support the local ecosystem

Desertification The process by which land in arid or semiarid areas becomes more desert-like.

Desertification Too many crops are planted too frequently, combined with overgrazing, the land has fewer plants to hold the topsoil in place. Therefore, large arid areas have become desert and can no longer produce food.

Soil Conservation Building soil-retaining terraces Contour plowing Leaving strips of vegetation No-till farming

Enriching the Soil Traditional farming methods used organic matter to enrich the soil. The organic matter decomposes and adds nutrients to the soil and improves the texture.

Enriching the Soil Today, inorganic fertilizers are used to enrich soil. Inorganic fertilizers contain Nitrogen Phosphorus Potassium Without these fertilizers, world food production would less than half of what it is today.

Enriching the Soil Compost is partly decomposed organic matter

Salinization The accumulation of salts in the soil Usually occurs in areas with low rainfall Irrigation water comes from rivers and groundwater, which is saltier than rainwater. When water evaporates from irrigated land, salts are left behind. Eventually, the soil may become so salty that plants cannot survive.

Salinization Irrigation can also cause salinization by raising groundwater levels temporarily. Salinization can be slowed if irrigation canals are lined to prevent water from seeping into the soil.

Pest Control Pests destroy about 33% of the world’s potential food harvest. Crops in tropical areas suffer greater insect damage because insects grown and reproduce faster.

Pest Any organism that occurs where it is not wanted or that occurs in large enough numbers to cause economic damage.

Crop plants vs. Wild plants More protection Grown throughout landscape Pest predators live on/near plant Evolved defenses Crops Plants Grown together in a large field = easy access to one-stop food source

Crop plants vs. Wild plants

Pesticides Chemicals used to kill insects, weeds, and other crop pests Can harm beneficial plants, insects, wildlife, and humans

Pesticides Spraying large amounts  resistance Resistance is the ability to survive exposure to a particular pesticide (pest is not killed)

Pesticides Human Health Concerns: Increase cancer rate among children Can cause nervous system disorders Pesticide workers become ill People who live nearby may be endangered by accidental chemical leaks

Pesticides: Human Health Concerns child of farm workers, born with birth defects attributable to pesticides (PBP) Burn from pesticide exposure

Persistent Pesticides Do not break down rapidly into harmless chemicals in nature They end up accumulating in the water and soil.

Persistent Pesticides DDT (dichlorodiphenyltrichloroethane) was banned in the United States in the 1970s as a persistent pesticide. It can still be detected in the environment and has been found in women’s breast milk.

Biological Pest Control The use of living organisms to control pests Use of natural/wild enemies to control pests

Pathogens Organisms that cause disease Bacillus thuringiensis (Bt): a bacteria that is the most common pathogen used to control pests

Plant Defenses Scientists and farmers have bred plant varieties that have defenses against pests. If you buy a plant or seed with ‘VNT’ on the label means it is resistant to certain fungi, worms, and viruses.

Disrupting Insect Breeding Growth Regulator- a chemical that interferes with some stage of a pest’s life cycle Example: flea pills for dogs Flea sucks the dog’s blood and ingests growth regulator Growth regulator stops the flea’s eggs from developing into adult fleas

Disrupting Insect Breeding Pheromones- chemicals produced by one organism that affect the behavior of another organism; male & female attraction Treating crops with pheromones can confuse the pests and interfere with mating

Integrated Pest Management The modern method of controlling pests on crops The goal is to reduce economic damage to crops.

Integrated Pest Management Biological methods are the first methods used to control a pest. So, natural predators, pathogens, and parasites of the pest may be introduced.

Genetic Engineering The genetic material in a living cell is modified for medical or industrial use. This involves isolating genes from one organism and implanting them into another.

Genetic Engineering The plants that result from genetic engineering are called genetically modified (GM) plants.

Sustainable Agriculture Farming that conserves natural resources and helps keep the land productive indefinitely Also called low-input farming

Sustainable Agriculture Characteristics Minimizes the use of energy and water Reduces the use of fertilizer and pesticides Involves planting productive, pest-resistant crops Plants crops that require little energy and water

Domesticated Animals To include: Sheep, horses, dogs, chickens, pigs, goats, fish, cattle, bees, and shellfish.

•Fish are an important food source to human. Food From Water •Fish are an important food source to human. •Harvesting fish is an important industry worldwide. •Environmental pressure: Overharvesting. •Overharvesting occurs when humans catch and remove more organisms within a population faster than the population can replenish.

Aquaculture To deter overharvesting, we began to raise aquatic organism for human consumption, aka. Aquaculture.

Aquaculture There are a number of aqua cultural methods used today. Oyster farms

Aquaculture The most common is fish farms. They generally consist of many individual ponds that contain fish at specific stages of development.

Aquaculture The ranch method is also used, fish such as salmon are raised until they reach a certain age then released.

Environmental Damage As with other food production methods, environmental issues arise with poor management. Organisms create waste which pollute water. Depletion of water resources. Destruction of wetlands.

Livestock Animals raised to be sold for profit.

Developing Countries Rely on livestock for food, wool, leather, eggs, to pull carts and plows.

Ruminants Those animals that are cud-chewing and have three-or four –chambered stomachs.

Ruminants Ruminants have microorganisms in their intestines that aid in digesting plant materials that humans cannot breakdown. When we consume meat, we are digesting the plant material that we cannot obtain from plants ourselves.

Poultry Since 1961, the chicken population worldwide has increased greater than any other livestock population.

What is it good for? The meat and eggs provide a source of essential amino acids, the building block of proteins.