Food, Soil, and Pest Management. Chapter 10

Transcription

1 Food, Soil, and Pest Management Chapter 10

2 Three big ideas ~ 1billion do not get enough to eat and ~1billion people eat too much. Modern industrialized agriculture has a greater harmful impact on the environment than any other human activity. More sustainable forms of food production will greatly reduce the harmful environmental impacts of industrialized food production systems while likely increasing food security.

3 Section 10-1 WHAT IS FOOD SECURITY AND WHY IS IT DIFFICULT TO ATTAIN?

4 Many people suffer from chronic health and malnutrition Food security means having daily access to enough nutritious food to live an active and healthy life. One of every six people in less-developed countries is not getting enough to eat, facing food insecurity living with chronic hunger and poor nutrition, which threatens their ability to lead healthy and productive lives. The root cause of food insecurity is poverty. Other obstacles to food security are political upheaval, war, corruption, and bad weather, including prolonged drought, flooding, and heat waves.

5 Starving children collecting ants in Sudan, Africa

6 Many people do not get enough vitamins and minerals Chronic lack of iodine can cause stunted growth, mental retardation, and goiter. Almost one-third of the world s people do not get enough iodine in their food and water. According to the FAO and the WHO, eliminating this serious health problem would cost the equivalent of only 2 3 cents per year for every person in the world.

7 Oil palm plantation once covered with tropical rain forest

8 Growth in global grain production of wheat, corn, and rice between

9 Global seafood production,

10 Food production s harmful environmental effects

11 Topsoil erosion is a serious problem in some parts of the world

12 Sand dunes threaten to take over an oasis in West Africa

13 Variation in desertification in arid and semiarid lands, 2007

14 Genetically modified crops and foods have advantages and disadvantages

15 Soil conservation methods

16 Three types of systems commonly used to irrigate crops

17 Ways to prevent soil salinization and ways to clean it up

18 Practice more sustainable aquaculture

19 Animal feedlots and confined animal feeding operations have advantages and disadvantages

20 Aquaculture has advantages and disadvantages

21 The efficiency of converting grain into animal protein varies

22 More sustainable, low-input food production has a number of major components

23 Major advantages of organic farming over conventional

24 Ways you can eat more sustainably

25 Synthetic pesticides: advantages and disadvantages

26 You can reduce your exposure to pesticides

27 Many people suffer from chronic health and malnutrition To maintain good health and resist disease, individuals need fairly large amounts of macronutrients, such as carbohydrates, proteins and fats, and smaller amounts of micronutrients vitamins and minerals. People who cannot grow or buy enough food to meet their basic energy needs suffer from chronic undernutrition, or hunger. Many suffer from chronic malnutrition a deficiency of protein and other key nutrients, which weakens them, makes them more vulnerable to disease, and hinders the normal development of children.

28 Many people do not get enough vitamins and minerals Deficiency of one or more vitamins and minerals, usually vitamin A, iron, and iodine. Some 250, ,000 children younger than age 6 go blind each year from a lack of vitamin A, and within a year, more than half of them die. Lack of iron causes anemia which causes fatigue, makes infection more likely, and increases a woman s chances of dying from hemorrhage in childbirth. 1/5 people in the world suffers from iron deficiency.

29 Many people have health problems from eating too much Overnutrition occurs when food energy intake exceeds energy use, causing excess body fat. Face similar health problems as those under: lower life expectancy, greater susceptibility to disease and illness, and lower productivity and life quality. Globally about 925 million people have health problems because they do not get enough to eat, and about 1.1 billion people face health problems from eating too much. About 68% of American adults are overweight and half of those people are obese. Obesity plays a role in four of the top ten causes of death in the United States heart disease, stroke, Type 2 diabetes, and some forms of cancer.

30 Section 10-2 HOW IS FOOD PRODUCED?

31 Food production has increased dramatically About 10,000 years ago, humans began to shift from hunting for and gathering their food to growing it and raising animals for food and labor. Today, three systems supply most of our food. Croplands produce mostly grains. Rangelands, pastures, and feedlots produce meat. Fisheries and aquaculture provide us with seafood. About 66% of the world s people survive primarily by eating rice, wheat, and corn. Only a few species of mammals and fish provide most of the world s meat and seafood.

32 Food production has increased dramatically Since 1960, there has been an increase in global food production from all three of the major food production systems because of technological advances. Tractors, farm machinery and high-tech fishing equipment. Irrigation. Inorganic chemical fertilizers, pesticides, highyield grain varieties, and industrialized production of livestock and fish.

33 Industrialized crop production relies on high-input monocultures Agriculture used to grow crops can be divided roughly into two types: Industrialized agriculture, or high-input agriculture, uses heavy equipment and large amounts of financial capital, fossil fuel, water, commercial inorganic fertilizers, and pesticides to produce single crops, or monocultures. Major goal of industrialized agriculture is to increase yield, the amount of food produced per unit of land. Used on about 25% of the world s cropland, mostly in moredeveloped countries, and produces about 80% of the world s food.

34 Industrialized crop production relies on high-input monocultures Plantation agriculture is a form of industrialized agriculture used primarily in tropical lessdeveloped countries. Grows cash crops such as bananas, soybeans, sugarcane, coffee, palm oil, and vegetables. Crops are grown on large monoculture plantations, mostly for export to more-developed countries. Modern industrialized agriculture violates the three principles of sustainability by relying heavily on fossil fuels, reducing natural and crop biodiversity, and neglecting the conservation and recycling of nutrients in topsoil.

35 Traditional agriculture often relies on low-input polycultures Traditional agriculture provides about 20% of the world s food crops on about 75% of its cultivated land, mostly in less-developed countries. There are two main types of traditional agriculture. Traditional subsistence agriculture supplements energy from the sun with the labor of humans and draft animals to produce enough crops for a farm family s survival, with little left over to sell or store as a reserve for hard times. In traditional intensive agriculture, farmers increase their inputs of human and draft-animal labor, animal manure for fertilizer, and water to obtain higher crop yields, some of which can be sold for income.

36 Traditional agriculture often relies on low-input polycultures Many traditional farmers grow several crops on the same plot simultaneously, a practice known as polyculture. Crop diversity reduces the chance of losing most or all of the year s food supply to pests, bad weather, and other misfortunes. Crops mature at different times, provide food throughout the year, reduce the input of human labor, and keep the soil covered to reduce erosion from wind and water.

37 Traditional agriculture often relies on low-input polycultures Lessens need for fertilizer and water, because root systems at different depths in the soil capture nutrients and moisture efficiently. Insecticides and herbicides are rarely needed because multiple habitats are created for natural predators of crop-eating insects, and weeds have trouble competing with the multitude of crop plants. On average, such low-input polyculture produces higher yields than does high-input monoculture.

38 A closer look at industrialized crop production Farmers can produce more food by increasing their land or their yields per acre. Since 1950, about 88% of the increase in global food production has come from using high-input industrialized agriculture to increase yields in a process called the green revolution. Three steps of the green revolution: First, develop and plant monocultures of selectively bred or genetically engineered high-yield varieties of key crops such as rice, wheat, and corn.

39 A closer look at industrialized crop production Second, produce high yields by using large inputs of water and synthetic inorganic fertilizers, and pesticides. Third, increase the number of crops grown per year on a plot of land through multiple cropping. The first green revolution used high-input agriculture to dramatically increase crop yields in most of the world s more-developed countries, especially the United States, between 1950 and 1970.

40 A closer look at industrialized crop production A second green revolution has been taking place since Fast-growing varieties of rice and wheat, specially bred for tropical and subtropical climates, have been introduced into middle-income, less-developed countries such as India, China, and Brazil. Producing more food on less land has helped to protect some biodiversity by preserving large areas of forests, grasslands, wetlands, and easily eroded mountain terrain that might otherwise be used for farming.

41 A closer look at industrialized crop production Largely because of the two green revolutions, world grain production tripled between 1961 and People directly consume about 48% of the world s grain production. About 35% is used to feed livestock and indirectly consumed by people who eat meat and meat products. The remaining 17% (mostly corn) is used to make biofuels such as ethanol for cars and other vehicles.

42 A closer look at industrialized crop production In the U.S., industrialized farming has evolved into agribusiness, as a small number of giant multinational corporations increasingly control the growing, processing, distribution, and sale of food in U.S. and global markets. Since 1950 U.S. industrialized agriculture has more than doubled the yields of key crops such as wheat, corn, and soybeans without cultivating more land. Americans spend only about 13% of their disposable income on food, compared to the percentages up to 50% that people in China and India and most other less-developed countries have to pay for food.

43 Crossbreeding and genetic engineering produce varieties of crops and livestock Crossbreeding through artificial selection has been used for centuries by farmers and scientists to develop genetically improved varieties of crops and livestock animals. Such selective breeding in this first gene revolution has yielded amazing results; ancient ears of corn were about the size of your little finger, and wild tomatoes were once the size of grapes. Typically takes 15 years or more to produce a commercially valuable new crop variety, and it can combine traits only from genetically similar species. Typically, resulting varieties remain useful for only 5 10 years before pests and diseases reduce their efficacy.

44 Crossbreeding and genetic engineering produce varieties of crops and livestock Modern scientists are creating a second gene revolution by using genetic engineering to develop genetically improved strains of crops and livestock. Alters an organism s genetic material through adding, deleting, or changing segments of its DNA to produce desirable traits or to eliminate undesirable ones (gene splicing); resulting organisms are called genetically modified organisms. Developing a new crop variety through gene splicing is faster selective breeding, usually costs less, and allows for the insertion of genes from almost any other organism into crop cells.

45 Crossbreeding and genetic engineering produce varieties of crops and livestock Currently, at least 70% of the food products on U.S. supermarket shelves contain some form of genetically engineered food or ingredients, but no law requires the labeling of GM products. Certified organic food, which is labeled as makes no use of genetically modified seeds or ingredients. Bioengineers plan to develop new GM varieties of crops that are resistant to heat, cold, herbicides, insect pests, parasites, viral diseases, drought, and salty or acidic soil. They also hope to develop crop plants that can grow faster and survive with little or no irrigation and with less fertilizer and pesticides.

46 Meat production has grown steadily Meat and animal products such as eggs and milk are good sources of high-quality protein and represent the world s second major food-producing system. Between 1961 and 2010, world meat production mostly beef, pork, and poultry increased more than fourfold and average meat consumption per person more than doubled. Global meat production is likely to more than double again by 2050 as affluence rises and more middleincome people begin consuming more meat and animal products in rapidly developing countries such as China and India.

47 Meat production has grown steadily About half of the world s meat comes from livestock grazing on grass in unfenced rangelands and enclosed pastures. The other half is produced through an industrialized system in which animals are raised mostly in densely packed feedlots and concentrated animal feeding operations (CAFOs), where they are fed grain, fish meal, or fish oil, which are usually doctored with growth hormones and antibiotics. Feedlots and CAFOs, and the animal wastes and runoff associated with them, create serious environmental impacts on the air and water.

48 Industrialized food production requires huge inputs of energy The industrialization of food production has been made possible by the availability of energy, mostly from nonrenewable oil and natural gas. Energy is needed to run farm machinery, irrigate crops, and produce synthetic pesticides and synthetic inorganic fertilizers, as well as to process food and transport it long distances within and between countries. As a result, producing, processing, transporting, and consuming industrialized food result in a large net energy loss.

49 Section 10-3 WHAT ENVIRONMENTAL PROBLEMS ARISE FROM INDUSTRIALIZED FOOD PRODUCTION?

50 Producing food has major environmental impacts Spectacular increases in the world s food production since The bad news is the harmful environmental effects associated with such production increases. According to many analysts, agriculture has a greater total harmful environmental impact than any human activity. These environmental effects may limit future food production and make it unsustainable.

51 Topsoil erosion is a serious problem in parts of the world Soil erosion is the movement of soil components, especially surface litter and topsoil from one place to another by the actions of wind and water. Erosion of topsoil has two major harmful effects. Loss of soil fertility through depletion of plant nutrients in topsoil. Water pollution in nearby surface waters, where eroded topsoil ends up as sediment. This can kill fish and shellfish and clog irrigation ditches, boat channels, reservoirs, and lakes.

52 Topsoil erosion is a serious problem in parts of the world By removing vital plant nutrients from topsoil and adding excess plant nutrients to aquatic systems, we degrade the topsoil and pollute the water, and thus alter the carbon, nitrogen, and phosphorus cycles.

53 Drought and human activities are degrading drylands Desertification in arid and semiarid parts of the world threatens livestock and crop contributions to the world s food supply. Desertification occurs when the productive potential of topsoil falls by 10% or more because of a combination of prolonged drought and human activities that expose topsoil to erosion. The FAO s 2007 report on the Status of the World s Forests estimated that some 70% of world s arid and semiarid lands used for agriculture are degraded and threatened by desertification.

54 Excessive irrigation has serious consequences Irrigation boosts productivity of farms; roughly 20% of the world s cropland that is irrigated produces about 45% of the world s food. Most irrigation water is a dilute solution of various salts that are picked up as the water flows over or through soil and rocks. Repeated annual applications of irrigation water in dry climates lead to the gradual accumulation of salts in the upper soil layers a soil degradation process called salinization that stunts crop growth, lowers crop yields, and can eventually kill plants and ruin the land.

55 Excessive irrigation has serious consequences Severe salinization has reduced yields on at least 10% of the world s irrigated cropland, and almost 25% of irrigated cropland in the United States, especially in western states Irrigation can cause waterlogging, in which water accumulates underground and gradually raises the water table; at least one-tenth of the world s irrigated land suffers from waterlogging, and the problem is getting worse. Excessive irrigation contributes to depletion of groundwater and surface water supplies.

56 Agriculture contributes to air pollution and projected climate change Agricultural activities create a lot of air pollution. Account for more than 25% of the human-generated emissions of carbon dioxide, other greenhouse gases. Industrialized livestock production alone generates about 18% of the world s greenhouse gases; cattle and dairy cows release the greenhouse gas methane and methane is generated by liquid animal manure stored in waste lagoons. Nitrous oxide, with about 300 times the warming capacity of CO 2 per molecule, is released in huge quantities by synthetic inorganic fertilizers as well as by livestock manure.

57 Food and biofuel production systems have caused major losses of biodiversity Natural biodiversity and some ecological services are threatened when forests are cleared and grasslands are plowed up and replaced with croplands used to produce food or biofuels, such as ethanol. There is increasing loss of agrobiodiversity, the world s genetic variety of animal and plant species. In the United States, about 97% of the food plant varieties that were available to farmers in the 1940s no longer exist, except perhaps in small amounts in seed banks and in the backyards of a few gardeners. The world s genetic library, which is critical for increasing food yields, is rapidly shrinking.

58 There is controversy over genetically engineered foods Controversy has arisen over the use of genetically modified (GM) food and other products of genetic engineering. Its producers and investors see GM food as a potentially sustainable way to solve world hunger problems and improve human health. Some critics consider it potentially dangerous Frankenfood. Recognize the potential benefits of GM crops. Warn that we know too little about the long-term potential harm to human health and ecosystems from the widespread use of such crops.

59 There is controversy over genetically engineered foods Warn that GM organisms released into the environment may cause some unintended harmful genetic and ecological effects. Genes in plant pollen from GM crops can spread among nonengineered species. The new strains can then form hybrids with wild crop varieties, which could reduce the natural genetic biodiversity of wild strains. Most scientists and economists who have evaluated the genetic engineering of crops believe that its potential benefits will eventually outweigh its risks. Others have serious doubts about the ability of GM crops to increase food security compared to other more effective and sustainable alternative solutions.

60 There are limits to expansion of the green revolution Factors that have limited the current and future success of the green revolution: Without huge inputs of inorganic fertilizer, pesticides, and water, most green revolution and genetically engineered crop varieties produce yields that are no higher (and are sometimes lower) than those from traditional strains. High inputs cost too much for most subsistence farmers in less-developed countries.

61 There are limits to expansion of the green revolution Scientists point out that continuing to increase these inputs eventually produces no additional increase in crop yields. Since 1978, the amount of irrigated land per person has been declining, due to population growth, wasteful use of irrigation water, soil salinization, and depletion of both aquifers and surface water, and the fact that most of the world s farmers do not have enough money to irrigate their crops. We can get more crops per drop of irrigation water by using known methods and technologies to greatly improve the efficiency of irrigation.

62 There are limits to expansion of the green revolution Clearing tropical forests and irrigating arid land could more than double the world s cropland, but much of this land has poor soil fertility, steep slopes, or both. Cultivating such land usually is expensive, is unlikely to be sustainable, and reduces biodiversity by degrading and destroying wildlife habitats During this century, fertile croplands in coastal areas are likely to be flooded by rising sea levels resulting from projected climate change. Food production could drop sharply in some major foodproducing areas because of increased drought and longer and more intense heat waves, also resulting from projected climate change.

63 Industrialized meat production has harmful environmental consequences Producing meat by using feedlots and other confined animal production facilities increases meat production, reduces overgrazing, and yields higher profits. Such systems use large amounts of energy (mostly fossil fuels) and water and produce huge amounts of animal waste that sometimes pollute surface water and groundwater and saturate the air with their odors and emitting large quantities of climate-changing greenhouse gases into the atmosphere.

64 Industrialized meat production has harmful environmental consequences Meat produced by industrialized agriculture is artificially cheap harmful environmental and health costs are not included in the prices. Overgrazing and soil compaction and erosion by livestock have degraded about 20% of the world s grasslands and pastures. Rangeland grazing and industrialized livestock production cause about 55% of all topsoil erosion and sediment pollution, and 33% of the water pollution that results from runoff from excessive inputs of synthetic fertilizers.

65 Industrialized meat production has harmful environmental consequences The use of fossil fuels energy pollutes the air and water, and emits greenhouse gases. Use of antibiotics is widespread in industrialized livestock production facilities. 70% of all antibiotics used in the United States are added to animal feed to prevent the spread of diseases in crowded feedlots and CAFOs and to make the livestock animals grow faster.

66 Industrialized meat production has harmful environmental consequences Widespread antibiotic use in livestock is an important factor in the rise of genetic resistance among many disease-causing microbes. Reduces the effectiveness of some antibiotics used to treat infectious diseases in humans. Promotes the development of new and aggressive disease organisms that are resistant to all but a very few antibiotics currently available. Animal waste produced by U.S. meat is roughly 130 times that of its human population.

67 Section 10-4 HOW CAN WE PROTECT CROPS FROM PESTS MORE SUSTAINABLY?

68 Nature controls the populations of most pests A pest is any species that interferes with human welfare by competing with us for food, invading homes, lawns and gardens, destroying building materials, spreading disease, invading ecosystems, or simply being a nuisance. Worldwide, only about 100 species of plants ( weeds ), animals (mostly insects), fungi, and microbes cause most of the damage to the crops we grow.

69 Nature controls the populations of most pests In natural ecosystems and many polyculture agroecosystems, natural enemies (predators, parasites, and disease organisms) control the populations of most potential pest species. Spiders kill far more crop-eating insects every year than humans do by using chemicals. When we clear forests and grasslands, plant monoculture crops, and douse fields with chemicals that kill pests, we upset many of these natural population checks and balances that help to maintain biodiversity.

70 We use pesticides to help control pest populations Development of a variety of synthetic pesticides chemicals used to kill/control populations of organisms that we consider undesirable such as insects, weeds, and mice. Common types of pesticides include insecticides (insect killers), herbicides (weed killers), fungicides (fungus killers), and rodenticides (rat and mouse killers). Plants produce chemicals called biopesticides to ward off, deceive, or poison the insects and herbivores that feed on them. Since 1950, pesticide use has increased more than 50- fold, and most of today s pesticides are times more toxic than those used in the 1950s. Use of biopesticides is on the rise.

71 We use pesticides to help control pest populations Broad-spectrum agents are toxic to many pests, but also to beneficial species. Examples are chlorinated hydrocarbon compounds, such as DDT, and organophosphate compounds, such as malathion and parathion. Selective, or narrow spectrum, agents are effective against a narrowly defined group of organisms. Examples are algaecides for algae and fungicides for fungi.

72 We use pesticides to help control pest populations Pesticides vary in their persistence, the length of time they remain deadly in the environment. DDT and related compounds remain in the environment for years and can be biologically magnified in food chains and webs. Organophosphates are active for days or weeks and are not biologically magnified but can be highly toxic to humans.

73 We use pesticides to help control pest populations In the United States, about 25% of pesticide use is on houses, gardens, lawns, parks, playing fields, swimming pools, and golf courses, with the average lawn receiving ten times more synthetic pesticides per unit of land area than an equivalent amount of cropland. In 1962, biologist Rachel Carson warned against relying primarily on synthetic organic chemicals to kill insects and other species we regard as pests.

74 Pesticide use has not reduced U.S. crop losses to pests Synthetic pesticide use has not reduced U.S. crop losses to pests, mostly because of genetic resistance and reduction of natural predators. Three conclusions from a study that evaluated data from more than 300 agricultural scientists and economists: Between 1942 and 1997, estimated crop losses from insects almost doubled from 7% to 13%, despite a 10-fold increase in the use of synthetic insecticides.

75 Pesticide use has not reduced U.S. crop losses to pests The estimated environmental, health, and social costs of pesticide use in the United States are $5 10 in damages for every dollar spent on pesticides. Alternative pest management practices could cut the use of synthetic pesticides by half on 40 major U.S. crops without reducing crop yields The pesticide industry disputes these findings.

76 CASE STUDY: Ecological Surprises: The Law of Unintended Consequences In the 1950s, dieldrin (a DDT relative) was used to eliminate malaria in North Borneo. This started an unexpected chain of negative effects. Small insect-eating lizards that lived in the houses died after eating dieldrin-contaminated insects. Cats died after feeding on the lizards. Rats flourished and villagers became threatened by plague carried by rat fleas. The WHO successfully parachuted healthy cats onto the island to help control the rats.

77 CASE STUDY: Ecological Surprises: The Law of Unintended Consequences The villagers roofs fell in. The dieldrin had killed wasps and other insects that fed on a type of caterpillar that was not affected by the insecticide. The caterpillar population exploded, and ate the leaves used to thatch roofs. Ultimately, both malaria and the unexpected effects of the spraying program were brought under control.

78 Laws and treaties can help to protect us from the harmful effects of pesticides In the U.S., three federal agencies, the EPA, the USDA, and the FDA regulate the sale and use of pesticides under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), first passed in 1947 and amended in Under FIFRA, the EPA was supposed to assess the health risks of the active ingredients in synthetic pesticide products already in use. After more than 30 years, less than 10% of the active ingredients in pesticide products have been tested for chronic health effects, due to lack of funding.

79 Laws and treaties can help to protect us from the harmful effects of pesticides In 1996, Congress passed the Food Quality Protection Act, due to growing scientific evidence and citizen pressure concerning the effects of small amounts of pesticides on children. Act requires the EPA to reduce the allowed levels of pesticide residues in food by a factor of 10 when there is inadequate information on the potentially harmful effects on children. Between 1972 and 2010, the EPA used FIFRA to ban or severely restrict the use of 64 active pesticide ingredients, including DDT and most other chlorinated hydrocarbon insecticides.

80 Laws and treaties can help to protect us from the harmful effects of pesticides Up to 98% of the potential risk of developing cancer from pesticide residues on food grown in the U.S. would be eliminated if EPA standards were as strict for pre-1972 pesticides as they are for later ones. Banned/unregistered pesticides may be manufactured in one country and exported to other countries. In what environmental scientists call a circle of poison, or the boomerang effect, residues of some banned or unapproved chemicals used in synthetic pesticides exported to other countries can return to the exporting countries on imported food.

81 There are alternatives to synthetic pesticides Many scientists believe we should greatly increase the use of biological, ecological, and other alternative methods for controlling pests and diseases that affect crops and human health. Here are some of these alternatives: Fool the pest. A variety of cultivation practices can be used to fake out pests. Provide homes for pest enemies. Implant genetic resistance.

82 There are alternatives to synthetic pesticides Bring in natural enemies. Use biological control by importing natural predators, parasites, and disease-causing bacteria and viruses. Use insect perfumes. Bring in the hormones. Reduce use of synthetic herbicides to control weeds.

83 Integrated pest management is a component of more sustainable agriculture Many pest control experts and farmers believe the best way to control crop pests is a carefully designed integrated pest management (IPM) program. Farmers develop a carefully designed control program that uses a combination of cultivation, biological, and chemical tools and techniques. The overall aim of IPM is to reduce crop damage to an economically tolerable level. Farmers first use biological methods (natural predators, parasites, and disease organisms) and cultivation controls (such as rotating crops, altering planting time, and using large machines to vacuum up harmful bugs).

84 Integrated pest management is a component of more sustainable agriculture IPM can also reduce inputs of fertilizer and irrigation water, and slow the development of genetic resistance, because pests are attacked less often and with lower doses of pesticides. Disadvantages of IPM: It requires expert knowledge about each pest situation and takes more time than does using conventional pesticides. Methods developed for a crop in one area might not apply to areas with even slightly different growing conditions.

85 Section 10-5 HOW CAN WE IMPROVE FOOD SECURITY?

86 Use government policies to improve food production and security Agriculture is a financially risky business because farmers have a good or bad year depending on factors over which they have little control: weather, crop prices, crop pests and diseases, loan interest rates, and global markets. Governments use two main approaches to influence food production: Control prices. Provide subsidies.

87 Section 10-6 HOW CAN WE PRODUCE FOOD MORE SUSTAINABLY?

88 Reduce soil erosion Soil conservation involves using a variety of ways to reduce soil erosion and restore soil fertility, mostly by keeping the soil covered with vegetation. Some of the methods farmers can use to reduce soil erosion: Terracing and contour planting are ways to grow food on steep slopes without depleting topsoil. Strip cropping involves planting alternating strips of a row crop and another crop that completely covers the soil, called a cover crop.

89 Reduce soil erosion Alley cropping, or agroforestry involves one or more crops planted together in strips or alleys between trees and shrubs, which provide shade. Farmers can establish windbreaks, or shelterbelts, of trees around crop fields to reduce wind erosion. Conservation tillage farming by using special tillers and planting machines that drill seeds directly through crop residues into the undisturbed soil. Retire the estimated one-tenth of the world s marginal cropland that is highly erodible and accounts for the majority of the world s topsoil erosion.

90 Restore soil fertility Topsoil conservation is the best way to maintain soil fertility, with restoring some of the lost plant nutrients being the next option. Organic fertilizer from plant and animal materials. Animal manure: the waste of cattle, horses, poultry, and other farm animals adding organic nitrogen, stimulating the growth of beneficial soil bacteria and fungi. Green manure: consists of freshly cut or growing green vegetation that is plowed into the topsoil to increase the organic matter and humus available to the next crop. Compost is produced when microorganisms in soil break down organic matter in the presence of oxygen.

91 Restore soil fertility Organic agriculture uses only organic fertilizers and crop rotation to replenish the nutrients. Synthetic inorganic fertilizers are usually inorganic compounds that contain nitrogen, phosphorus, and potassium. Inorganic fertilizer use has grown more than 900% since 1950; now about one-fourth of the world s crops. Fertilizer runoff can pollute nearby bodies of water and coastal estuaries where rivers empty into the sea. They do not replace organic matter. To completely restore nutrients to topsoil, both inorganic and organic fertilizers should be used.

92 Reduce soil salinization and desertification One way to prevent and deal with soil salinization is to reduce the amount of water that is put onto crop fields through use of modern efficient irrigation. Drip, or trickle irrigation, also called microirrigation, is the most efficient way to deliver small amounts of freshwater to crops precisely. These systems drastically reduce freshwater waste because 90 95% of the water input reaches the crops. By using less freshwater, they also reduce the amount of harmful salt that irrigation water leaves in the soil.

93 Produce meat more efficiently and eat less meat Meat production and consumption account for the largest contribution to the ecological footprints of most individuals in affluent nations. If everyone in the world today was on the average U.S. meat-based diet, the current annual global grain harvest could sustainably feed only about one-third of the world s current population.

94 Produce meat more efficiently and eat less meat More sustainable meat production and consumption involves shifting from less grainefficient forms of animal protein, (beef, carnivorous fish), to more grain-efficient forms (poultry, herbivorous farmed fish). Eating less meat by having one meatless day per week. Healthier to eat less meat. Replace meat with a balanced vegetarian diet.

95 Shift to more sustainable food production Industrialized agriculture produces large amounts of food at reasonable prices, but is unsustainable because it: Relies heavily on fossil fuels. Reduces biodiversity and agrobiodiversity. Reduces the recycling of plant nutrients back to topsoil.

96 Shift to more sustainable food production More sustainable, low-input agriculture has a number of major components. Organic farming. Sharply reduces the harmful environmental effects of industrialized farming and our exposure to pesticides. Encourages more humane treatment of animals used for food and is a more economically just system for farm workers and farmers. Requires more human labor than industrial farming. Yields can be lower but farmers do not have to pay for expensive synthetic pesticides, herbicides, and fertilizers; typically get higher prices for their crops.

97 Shift to more sustainable food Organic polyculture. production A diversity of organic crops is grown on the same plot. Use polyculture to grow perennial crops crops that grow back year after year on their own. Helps to conserve and replenish topsoil, requires and wastes less water, and reduces the need for fertilizers and pesticides. Reduces the air and water pollution associated with conventional industrialized agriculture. Shift from using imported fossil fuel to relying more on solar energy for food production.

98 Shift to more sustainable food production Five major strategies to help farmers and consumers make the transition to more sustainable agriculture: 1. Greatly increase research on more sustainable organic farming and perennial polyculture, and on improving human nutrition. 2. Establish education and training programs in more sustainable agriculture for students, farmers, and government agricultural officials. 3. Set up an international fund to give farmers in poor countries access to various types of more sustainable agriculture.

99 Shift to more sustainable food production 4. Replace government subsidies for environmentally harmful forms of industrialized agriculture with subsidies that encourage more sustainable agriculture. 5. Mount a massive program to educate consumers about the true environmental and health costs of the food they buy. This would help them understand why the current system is unsustainable, and it would help build political support for including the harmful costs of food production in the market prices of food.

100 Three big ideas About 925 million people have health problems because they do not get enough to eat and 1.1 billion people face health problems from eating too much. Modern industrialized agriculture has a greater harmful impact on the environment than any other human activity. More sustainable forms of food production will greatly reduce the harmful environmental impacts of industrialized food production systems while likely increasing food security.