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Chapter 15 Food and Agriculture. Section 1: Feeding the World. Famine : Malnutrition :. Widespread starvation caused by a shortage of food. In 1985, drought , erosion, and war caused a sever famine in Ethiopia. About 800 million people are undernourished each day.
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Famine: Malnutrition: • Widespread starvation caused by a shortage of food. • In 1985, drought , erosion, and war caused a sever famine in Ethiopia. • About 800 million people are undernourished each day. • A condition that occurs when people do not consume enough Calories (food energy) or do not eat a sufficient variety of foods to fulfill all of the body’s needs. • Occurs because of poverty, war, and transportation issues. • Many forms of malnutrition. • Protein-energy malnutrition results, affecting the normal physical and mental development of children.
Sources of Nutrition Available calorie supply per person/per day • Diet: The type and amount of food that a person eats. • A healthy diet is one that maintains a balance of the right amount of nutrients, minerals, and vitamins. • In most parts of the world, people eat large amounts of food that are high in carbohydrates - like rice, potatoes, and bread. • The food produced in the greatest quantity around the world is grains (rich in carbohydrates). • Besides grains, people eat fruits, vegetables, and smaller amounts of meats, nuts, and other foods that are rich in fats and proteins.
Food Efficiency: Yield: • A measure of the quantity of food produced on a given area of land with limited inputs of energy and resources. • An ideal food crop is one that efficiently produces a large amount of food with little negative impact on the environment. • The amount of food that can be • produced in a given area. • Researchers are interested in organisms that can thrive in various climates and that do not require large amounts of fertilizer, pesticides, or fresh water.
Facts About Food To raise crops: • Requires less water, less energy, and less land than raising animals. • More efficient to raise plants for food – this is why diets around the world are largely based on plants. • The human body depends on food to build and maintain body tissue. To raise animals: • Animals used as food are fed plants. • They only store 10 % of the energy from the plants – the rest is used to survive. • Meats provide high levels of nutrients.
Subsistence farmers: Poverty: • Farmers who grow only enough food for local use. • They work tiny plots of land trying provide enough food for their family and a little left over to sell. • The state or condition of having little or no money, goods, or means of support; condition of being poor. • Malnutrition generally occurs because of poverty. • Most are usually farm workers or subsistence farmers.
Green Revolution • Introduced new crop varieties with increased yields through the application of modern agricultural techniques. • Between 1950 and 1970, Mexico increased its production of wheat eight-fold and India doubled its production of rice without increasing the area of farmland used. Negative Impacts: • Costly to purchase seeds • Soil degradation • Overuse of water, pesticides, and fertilizers. Future of Crops: • Major research today is devoted to developing plant varieties that produce high yields of nutritious food on poor soil, using as little water and expensive chemicals as possible.
Soil Layers • Surface Litter: fallen leaves and partially decomposed organic matter • Topsoil: organic matter, living organisms, and rock particles • Zone of leaching: dissolved or suspended materials moving downward • Subsoil: larger rock particles with organic matter, and inorganic compounds • Rock particles: rock that has undergone weathering • Bedrock: solid rock layer
Arable Land: Top Soil: • Soil that can support the growth of healthy plants is called fertile soil. • Plant roots grow in topsoil. • Topsoil is the surface layer of the soil. • Usually richer in organic matter than subsoil. • Fertile topsoil is composed of: living organisms, rock particles, water, air, organic matter, and decomposing organisms. • Land that can be used to grow crops. • About 10 % of the Earth’s surface is arable land. • About 3 % of Earth’s surface is urban areas – and growing.
Agriculture: Traditional v’s Modern**Basic processes of farming include: plowing, fertilization, irrigation, and pest control Traditional Agriculture: • Plows are pushed by farmers or pulled by livestock. • Plowing helps crops grow by mixing soil nutrients, loosening soil particles, and uprooting weeds. • Organic fertilizers are used (manure) • Irrigated by water flowing through ditches. • Weeds removed by hand/machine. Modern: (industrialized countries) • Plowing done by machinery (burns fossil fuels) • Harvest by machinery. • Synthetic chemical used as fertilizers. • Overhead sprinklers/drip systems used to irrigation. • Synthetic chemicals used as pest control.
Erosion: Desertification: • The movement of rock and soil by wind and water. • Washes into nearby rivers or is blown away in clouds of dust. • In US – about ½ the original topsoil has been lost to erosion in the past 200 years. • The process by which land in arid or semiarid areas becomes more desert like. • Has happened as a result of land degradation. • Land degradation: when human activity or natural processes damage the land so that it can no longer support the local ecosystem.
Contour Plowing: No-till Farming: • Form of soil conservation to save topsoil. • Includes plowing across the slope of a hill instead of up and down the slope. • In traditional farming – after harvest – the soil is plowed to turn it over and bury the remains. • No-till farming: a crop is harvested without turning over the soil. • Seeds of the next crop are planted among the remains of the previous crop. • Previous crop holds soil in place.
Compost: Salinization: • Partly decomposed organic material. • Used to enrich soil. • Comes from many sources: cow manure, yard waste, crop waste • The accumulation of salts in the soil. • Major problem in places such as California and Arizona (low rainfall and naturally salty soil) • Irrigation comes from rivers and groundwater – which is naturally saltier than rainwater.
Pesticides: Pesticide Resistance: • Chemicals used to kill insects, weeds, and other crop pests. • Can harm beneficial plants and insects, wildlife, and even people. • Major crop pest: weeds, insects, and fungi • The ability to survive exposure to a particular pesticide. • More than 500 species of insects have developed resistance to pesticides since the 1940s.
Biological pest Control:the use of living organisms to control pests. • Pathogens: Organisms that cause disease are used. Most common: Bacillus thuringiensis(Bt). Used to kill the caterpillars of moths and butterflies. • Plant Defenses: Bred into plants. Can be resistant to fungi, worms, and viruses. Include: chemical compounds that repel pests and physical barriers like tougher skin. • Chemicals from Plants: Uses the plants’ defensive chemicals. Used mostly in home use insect sprays – because they are less harmful to people/pets.
Disrupting Insect Breeding Growth Regulator: Pheromones: Chemicals produced by one organism that influence the behavior of another organism. Can also be used in pest control. • A chemical that interferes with some stage of a pest’s life cycle. • Ex. : Once a month dog flea treatments (stops flea eggs from developing)
Integrated pest management: **It is a modern method of controlling pests on crops. **The goal is to reduce pest damage to a level that causes minimal economic damage. Includes: • Chemical pest control • Biological pest control • Mix of farming methods
Genetic Engineering: Sustainable Agriculture: • The technology in which genetic material in a living cell is modified for medical or industrial use. • Involves isolating genes from one organism and implanting them into another. • It is a faster way to produce the same results as plant breeding. • Also known as low-input farming. • Farming that conserves natural resources and helps keep the land productive indefinitely.
Overharvesting: Aquaculture: • Catching or removing from a population more organisms than the population can replace. • Governments have created no-fishing zones to lessen overharvesting. • The raising of aquatic organisms for human use or consumption. • Probably began in China about 4,000 years ago. • Today – China leads the world in using aquaculture.
Livestock: Domesticated Animals: • Domestic animals that are raised to be used on a farm or ranch or to be sold for profit. • Livestock farms produce most meat that is consumed in developed countries. • Ex: chickens, sheep, cattle, pigs • Animals that have been bred and managed for human use. • About 50 animals species have been domesticated. • India – has about 1/5 of the world’s population of cattle. Many are never killed or eaten – because they are sacred.
Ruminants: Poultry: • Cud-chewing mammals that have three or four chambered stomachs. • Ex: cattle, sheep, goats • Cud is the food these animals regurgitate from the 1st chamber of their stomachs and chew again to aid digestion. • Domesticated birds raised for meat and eggs. • Are good sources of essential amino acids. • Ex: chickens, turkeys • Since 1961, the population of chickens worldwide has increased more than any other livestock.
