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FOOD RESOURCES. PART-II. Types of Agriculture. Industrialized Agriculture – “Agribusiness ” or high-input agriculture Developed countries Land – moderate amount Labor – low Capital Costs – high (use a lot of fertilizer, pesticides, and irrigation systems) Energy Use (fossil fuels) – high
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FOOD RESOURCES PART-II
Types of Agriculture • Industrialized Agriculture – “Agribusiness” or high-input agriculture • Developed countries • Land – moderate amount • Labor – low • Capital Costs – high (use a lot of fertilizer, pesticides, and irrigation systems) • Energy Use (fossil fuels) – high • Yield -high • Environmental Impacts – high (soil degradation, pesticide resistance in agricultural pests)
Types of Agriculture • Intensive Traditional (Rice fields, China, Thailand) • Developing countries • Capital Costs – low (use fertilizer and will divert water for irrigation through dams on occasion) • Energy use (fossil fuels) – low • Environmental Impacts (low-moderate)
Subsistence Agriculture • Traditional agricultural methods, which are dependent on labor and a large amount of land to produce enough food to feed oneself and one’s family. • They will have little left over to sell or reserve for hard times. • Energy requirement: high (from humans and draft animals, rather than from fossil fuels)
Shifting Cultivation • Developing countries • Land – large tracts of tropical forests cleared and used for agriculture • Short period of cultivation are followed by longer periods of fallow. • Labor – low-moderate • Capital Costs – low (rarely use fertilizer) • Energy use – low to none • Shift agricultural plots of land until nutrients are restored to land. • Environmental Impacts (moderate) • Supports relatively small populations.
Slash-and burn agriculture • It is shifiting cultivation that involves clearing small patches of tropical forests to plant crops. • Tropical soils lose productivity quickly when they are cultivated, farmers move from one area of forest to another every three years or so. • It is land intensive.
Nomadic Herding • Developing countries • Land – large tracts • Labor – low • Capital Costs – low • Energy use (fossil fuels) – none • Yak in Tibet (Snow Leopard Video) • Nomadic herders must continually move their livestock to find adequate food for them.
INTERCROPPING • It is a form of intensive subsistence agriculture that involves growing a variety of plants simultaneously on the same field. • When certain crops are grown together, they produce higher yields than when they are grown as monocultures. • Intercropping discourages the buildup of any single pest species to economically destructive levels. • Native Americans practiced intercropping when they planted corn, bean, and squash seeds in the same mound of soil.
Intercropping by native Americans • Root systems of these plants grow to different depths, so they do not compete with one another for water and essential minerals. • Protein-rich bean crop fixes nitrogen that fertilizes the corn and squash plants naturally. • Example, carbohydrate rich grains such as corn next to protein-rich legumes such as alfalfa that fixes nitrogen in the soils due to Rhizobium sp.
Polyculture • A complex form of intercropping. Many different species/varieties of plants will mature at different times. This ensures year-round crop production and habitat for pests and wildlife. • Practiced in the tropics, fast- and slow-maturing crops are often planted together so that plants are harvested throughout the year. • Produces high sustainable yields. • Provides medicine, fuel, natural pesticides and natural fertilizers. • Reduces environmental degradation from pesticides and irrigation and reduces crop losses overall. • Vegetable crops and cereal grains, which mature first, might be planted with papayas and bananas, which mature later.
Domestication • The process of taming wild animals or adapting wild plants to serve humans; domestication markedly alters the characteristics of the domesticated organism. • During the domestication of plants and animals, much of the genetic diversity is lost because the farmer selects for propagation only those plants and animals with the most desirable agricultural characteristics. At the same time, other traits not of obvious value to humans are selected against. As a result, many of the high-yielding crops grown by modern agriculture are genetically uniform.
Domestication • The lower genetic diversity of domesticated animals and plants increases the likelihood that they will succumb to new strains of disease-causing organisms. • When a disease breaks out in a domesticated plant or animal population, the entire uniform population is susceptible. The loss is greater than it would be in a natural, varied population, in which at least some individual would contain genes to resist the disease-causing organism. • Read Page number 434-435 for more information in your text book and discuss with your partner.
Pre-Green revolution • 1912 – German chemist Fritz Haber developed a process for synthesizing ammonia directly from nitrogen and hydrogen. “The Haber Process” • At the start of World War I, in 1914, Germany was dependent on nitrate deposits in Chile for nitrogen containing compounds needed to manufacture explosives. • The Allied naval blockade of South America cut off this supply. • By fixing nitrogen from the air, Germany was able to continue explosives production. • From this incident and the development of the Haber process, scientists have continued to fix nitrogen to manufacture fertilizers that have increased crop yields. • Approximately 50 billion pounds of ammonia are manufactured annually in the USA = BIG BUSINESS! • The decision to award Fritz Haber the Nobel Prize for Chemistry in 1918 was the subject of considerable controversy since he served as chief of Germany’s Chemical Warfare Service and developed chlorine as a poison gas-weapon later used in Nazi Germany concentration camps. • He was awarded the Nobel Prize because it was believed that “the world would never go hungry again”. • The ultimate irony came in 1933 when Haber was expelled from Germany because he was Jewish!
Green Revolution • Using modern cultivation methods and the high-yielding varieties of certain staple crops to produce more food per acre of cropland is known as the green revolution. Norman Borlaug, a U.S scientist who worked on wheat in Mexico during the 1940s and 1950s, is credited with beginning the green revolution. • His introduction of a short-stemmed, hybrid strain of “miracle wheat” to Mexico and countries in South Asia was followed by the development by other plant breeders of high-yielding varieties of rice and other grain crops.
2nd Green Revolution • Introduction of genetically modified crops to obtain high yields. • New herbicides introduced.
New Green Revolution • “Sasakawa Global 2000” • Ryoichi Sasakawa, Norman Bourlag & Jimmy Carter • Goal: Obtain high yields in an environmentally friendly way by introducing • Integrated Management Plans (IPM’s) • Terracing • Intercropping.
Green Revolution (1950-1970) • Plant monocultures to obtain high yields. • Input pesticides and fertilizers to obtain high yields. • Increase frequency and intensity of cropping to obtain high yields. • Was all of this done to “feed the world” or make high profits?
Green Revolution • Critics of the green revolution argue • It has made developing countries dependent on imported technologies, such as agrochemical, tractors a t the expense of traditional agriculture. • Two important problems associated with higher crop production • High energy caused by the intensive use of commercial inorganic fertilizers and pesticides. • The environmental impacts of intensive agriculture, including the green revolution.
Trade-Offs Inorganic Commercial Fertilizers Disadvantages Advantages Easy to transport Easy to store Easy to apply Inexpensive to produce Help feed one of every three people in the world Without commercial inorganic fertilizers, world food output could drop by 40% Do not add humus to soil Reduce organic matter in soil Reduce ability of soil to hold water Lower oxygen content of soil Require large amounts of energy to produce, transport, and apply Release the greenhouse gas nitrous oxide (N2O) Runoff can overfertilize nearby lakes and kill fish
Efforts to increase food security in low-income, food-deficient countries • During the 1990s, the FAO initiated a special program for farmers in 19 nations, most in Africa. • Participating farmers are given genetically improved seeds, commercial inorganic fertilizers, and pesticides and are trained in improved agricultural techniques. • These farmers provide demonstrations to neighboring farmers on how to increase food production, reduce water use, control pests, and protect soil, and other natural resources. • In Ethiopia, this program doubled grain yields at demonstration sites.
The Environmental Impacts of Agriculture • The agricultural use of fossil fuels and pesticides produces air pollution • Untreated agricultural animal wastes and agricultural chemicals such as fertilizers and pesticides cause water pollution that reduces biological diversity, harms fisheries, and leads to outbreaks of nuisance species (algal blooms) • Surface-water pollution in the United States. It is significant in mid western states such as Iowa, Wisconsin, and Illinois. • Agricultural chemicals have been detected in water deep underground as well as in surface waters. • Nitrates are probably the most widespread groundwater contaminant in agricultural areas. • Residues of pesticides contaminate our food supply and reduce the number and diversity of beneficial microorganisms in the soil • Fishes and other aquatic organisms are sometimes killed by pesticide runoff into lakes, rivers and estuaries.
Colorado potato beetles on potato leaves • As a result of being exposed to heavy application of pesticides over the years, Colorado potato beetles are resistant to most insecticides registered for use on potatoes
Livestock • Cattle – beef = affluence • Horses • Oxen • Sheep • Chicken • hogs
Cattle Ranching Beef Cows Dairy Cows
Waste from livestock factories • In livestock factories, thousands of animals are confined to small pens in buildings the size of football fields. • Environmental problems • Air and water pollution • Manure produced by thousands of pigs in one livestock factory causes a severe waste disposal problem • Manure is stored in lagoons, that have the potential to pollute the soil, surface water and ground water. • People living near livestock factories dislike the odor.
Economics of Agriculture • AGRICULTURE MAKES UP 20% OF USA’S GNP! = BIG BUSINESS • High input = high output (high yields) • Industrial Agriculture uses: 1. tremendous amounts of energy (fossil fuels) 2. Moderate amount of land 3. fertilizers and pesticides Food costs/salary have decreased by 50% since 1940 due to “relatively” cheap energy (subsidies), mass growing and processing. ALL leading to environmental degradation. Environmental degradation costs billions of dollars to attempt to repair structure and function losses of ecosystems. Restoration of habitats usually will NOT replace the originally lost structure, function and values of ecosystems.
Economics of the Hamburger • 1 acre of forest supports 800,000 pounds of plants and animals. • 1 acre = 43, 560 square feet • 1 bovine = 200 pounds of actual beef • 200 pounds of beef = (800) 4 ounce hamburgers • 1 hamburger = ½ ton (1000 pounds) of forest products • 1 hamburger = 55 square feet of forest • Two 4oz. Hamburgers will fill 45-50 bowls with cooked cereal grains for undernutrition/malnutritioned children in the USA. • 2.1 million children under the age of 3 live in poverty in the USA!
Land degradation • The natural or human induced process that decreases the future ability of the land to support crops or livestock. • Soil erosion causes a decline in soil fertility, and the sediments lost by erosion damage water quality. • Compaction of soil by heavy machinery and water logging and salinization of soil from improper irrigation methods result in land degradation.
Habitat Fragmentation • Clearing grasslands and forests and draining wetlands to grow crops have resulted in habitat fragmentation. This has resulted in reduction in biological diversity. Many species have become endangered or threatened as a result of habitat loss created by agriculture
Cultivating Marginal Land • The United States had agricultural surplus during the 1980s, in part because farmers brought large amounts of marginal land into cultivation. This was ecologically unsound and some of the marginal farmlands are no longer used now.
Environmental Degradation From Terrestrial Food Production Transpiration Evaporation Waterlogging Less permeable clay layer
Environmental Degradation From Terrestrial Food Production Consequences Causes Overgrazing Deforestation Erosion Salinization Soil compaction Natural climate change Worsening drought Famine Economic losses Lower living standards Environmental refugees
Biodiversity Loss Soil Loss and degradation of habitat from clearing grasslands and forests and draining wetland Fish kills from pesticide runoff Killing of wild predators to protect livestock Loss of genetic diversity from replacing thousands of wild crop strains with a few monoculture strains Erosion Loss of fertility Salinization Waterlogging Desertification
Air Pollution Water Water waste Aquifer depletion Increased runoff and flooding from land cleared to grow crops Sediment pollution from erosion Fish kills from pesticide runoff Greenhouse gas emissions from fossil Fuel issue Other air pollutants from fossil fuel use Pollution from pesticide sprays Surface and groundwater pollution from pesticides and fertilizers Overfertilization of lakes and slow-moving rivers from runoff of nitrates and phosphates from fertilizers, livestock wastes, and food processing wastes
Solutions to Agricultural problems • Sustainable Agriculture • It is also called alternative or low-input agriculture, and involves certain modern agricultural techniques carefully combined with traditional farming methods from agricultural past. These methods help to maintain soil productivity and a healthy ecological balance while having minimal long-term impacts.
Some goals of sustainable agriculture • Increase biological diversity in crops and livestock • Minimize pesticide inputs • Maximize natural processes such as pest control and pollination. • Manage wetlands and water resource carefully • Minimize soil erosion through crop rotation, multiple cropping, conservation tillage and planting tracts of forest. • Improve soil fertility by adding organic and matter and managing soil biology to minimize commercial inorganic fertilizer inputs. • Avoid monoculture
Sustainable Agricultural Methods • Terracing • Contour Farming • Strip Cropping • Agroforestry (Alley Cropping) • Windbreaks • Conservation Tillage Farming • Salt Flushing • Gully Reclamation
Figure 14-13Page 284 Trade-Offs Conservation Tillage Disadvantages Advantages Can increase herbicide use for some crops Leaves stalks that can harbor crop pests and fungal diseases and increase pesticide use Requires investment in expensive equipment Reduces erosion Saves fuel Cuts costs Holds more soil water Reduces soil compaction Allows several crops per season Does not reduce crop yields Reduces CO2 release from soil
Figure 14-12Page 283 Solutions Soil Salinization Prevention Cleanup Flushing soil (expensive and wastes water) Not growing crops for 2-5 years Installing under- ground drainage systems (expensive) Reduce irrigation Switch to salt- tolerant crops (such as barley, cotton, sugar beet)
Alley cropping • Definition • Alley cropping is the planting of trees or shrubs in two • or more sets of single or multiple rows with agronomic, • horticultural, or forage crops cultivated in the alleys • between the rows of woody plants. • Purpose • Alley cropping is used to enhance or diversify farm • products, reduce surface water runoff and erosion, • improve utilization of nutrients, reduce wind erosion, • modify the microclimate for improved crop production, • improve wildlife habitat, and enhance the aesthetics • of the area.
