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Food and Agriculture Big question: how do humans meet their nutritional needs Bigger question: how do you answer the big question and not degrade the environment Sustainable agriculture Nutrition Average caloric need: 2200 cal/day Food production is adequate Barring disaster, food supplies will increase Food distribution is problem Food Distribution US, Canada, Western Europe, Australia—excess food for most Sub-Saharan Africa, portions of Mid-and Southeast Asia—most at risk for chronic under and malnourishment Food security—ability to obtain sufficient food on daily basis Food Shortages Famine—food shortages resulting in massive starvation Surface cause—lack of rainfall, insect attack Root causes—poverty, corrupt governments, political oppression & unrest, greedy power elite, war, genocide, etc. Food Shortages Amartya Sen—conflict and oppression: roots of famine Democratic countries with free press—no major famines Locals usually know how to deal with temporary climate fluctuations Conditions tend to stabilize Food Shortages Feeding camps—wrong way: dangerous and debilitating travel, crowded conditions, poor water supply and sewage treatment, etc People disrupted—no home, no jobs, no tools, no money, may not be able to return home Risk of permanent disruption Food Shortages Foreign assistance--wrong foods: for long term, storage and pest problems Wrong technologies—too high tech or energy-intensive: need trained workers and trouble shooters, reliable energy supply Nutrition Balanced diets: adequate calories and nutrients Malnourishment—lack of certain nutrients in food or inability to absorb Obesity—too many calories, sedentary life Anemia—low hemoglobin, iron deficiency Iodine-deficiency—(soils) Nutrition Vitamin A—blindness, problem with starch-based (processed) food Folic acid—neural tube defects Protein—kwashiorkor: protein deficiency, red-orange hair, bloated bellies, etc. Low cal., protein.—marasmus: shriveled up Balanced Diet Whole grains, unsaturated plant fats, legumes, nuts, vegetables, fruits, lean meats: emphasized Red meats, saturated fats, processed carbohydrates: decrease Major Food Sources Grains: wheat, rice, corn, barley, oats (grasses) Root crops: cassava, sweet potatoes, potatoes Legumes: beans, peas, soybeans Vegetables and fruit Meat and milk Seafood and fish Terrestrial Systems Plant and animal production Use of space, water, soils, chemical Serious impacts Food Systems Croplands—produce grain: about 77% of world’s food Rangeland—produce mostly meat from grazing livestock: about 16 % Ocean fisheries—produce fish and shellfish: about 7% Food Production 80% of world’s food supply produced by industrialized agriculture Aka high-input: large amounts of fossil fuel energy, H2O, synthetic fertilizer, pesticide Industrialized agriculture Single crops or monoculture Found on ¼ of all cropland Developed countries primarily Animal Production Livestock animals for sale Feedlots—densely populated: 4 month holdtime Hogs & chickens: densely populated pens/cages Plantation Agriculture Type of industrialized agriculture Tropical developing countries Cash crops Large monoculture plantations Sold to developed countries Traditional Agriculture 42% of people practice 1/5 of world’s food Subsistence—produce enough food for family’s use Human labor and draft animals Nomadic herding Shifting forest cultivation Traditional Agriculture Traditional intensive: more human and animal power, fertilizer use, water Enough surplus to sell Increase in food production 3 steps: Green Revolutions Develop and plant monocultures Produce high yields by using large inputs of fertilizer, water and pesticides Increase number of crops grown per year (multiple cropping) Green Revolutions First: high input farming, developed countries, 1950-1970 Second: fast-growing high yield dwarfs of wheat and rice, widespread, 1967 Third: GMOs? Requirements: fertile soil, ample water, fossil fuels to run machinery, apply farm chemicals, run pumps 8% of world’s energy input Soil Complex system capable of supporting plants Consists of; Disintegrated rock Organic matter Air Water Nutrients microorganisms Soils Thin covering Develop over long time Several layers—horizons Cross section of horizons—soil profile Surface Layer O horizon—surface litter layer, freshly fallen leaves, plant and animal waste, fungi, other organic materials, brown or black Topsoil A horizon— porous mixture of partially decomposed organic matter (humus) inorganic minerals, darker and looser than deeper layers O and A layers Plant roots anchored Water storage Bacteria, fungi, earthworms, small insects Complex food webs Decomposers rule Color— dark brown to black—fertile Yellow, orange, red—low organic, low nitrogen E Layer Eluviation--loss Zone of leaching: zone of dissolved or suspended materials B and C Horizons B—subsoil C—parent material Most of soil’s inorganic material C lies on bedrock Infiltration—downward movement of water through soil Leaching—dissolved minerals and organic matter C Layer Derived from bedrock Weathering—physical, chemical and biological breakdown of bedrock Physical: wind, rain Chemical interaction of H20, atmospheric gases—CO2, S Biological: lichens U.S. soils—parent material from glacial deposition, wind, water Texture and Porosity Size of particles—texture Amount of space between particles—porosity Clay, silt, sand, gravel Permeability—rate at which water and air move from upper to lower layers Soil Types Soil Conservation Service—classifies soils based on structure and composition, now Natural Resources Conservation Service Soil texture grid U.S.—soil orders—includes location and formation Impacts Soil Water Fertilizer Energy Local Soil Degradation Arable land—climate, water, rich organic fertile soil Degradation—natural & human activities decrease ability of soil to support wildlife, livestock or crops Erosion—loss of litter and topsoil Erosion Wind Water Sheet—thin layer Rill—small channels Gully—large ravines that impede normal tillage Erosion Plant cover removed by tree cutting, grazing or farming methods Drought 2 top layers lost Problems if layers are lost faster than they’re replaced Erosion Farming practice Crop type: row crops expose soil Plowing Machine use Loss of wind breaks Monoculture China, U.S., Canada Water Degradation Imported water—Central Valley, CA Subsidized costs Overused Unsuitable crops Waterlogging—soil air spaces filled with water, no O2, roots die Salinization: mineral salts accumulate Energy Use Industrialized agriculture in U. S. 4%: crops 2%: livestock 6%: food 5%: food distribution and preparation 17%: total U.S. commercial energy use Desertification Productive potential of arid or semi-arid lands falls by 10% or more Natural climate change Human activities reduce or degrade topsoil GMOs Genetically modified organisms Add genetic information into crop plant or livestock Soybeans, cotton, corn, tomatoes EU bans Ethics—corporations own the plants, make the pesticides and the fertilizer GMOs Less choice, corporations control everything Unintended consequences—Southern corn leaf blight Alter ecosystems—effects on other organisms, more invasive plants, more aggressive animals, etc Sustainable Agriculture Soil conservation—decrease erosion Contour plowing Strip farming—alternate crops in different rows, can be $$$$ Terracing Perennial species Cover crops Sustainable Agriculture Mulch—natural or plastic sheeting Reduced tillage—plowing techniques, minimal soil disruption Green fertilizer—alternate with legumes, nitrogen-fixing nodules Low-input Sustainable Family farms Pt. Reyes Sacramento delta Labor intensive Risky Questions?