Soil and Agriculture

1. Soil and Agriculture Chapter 14.1-14.2 Chapter 12

2. Things you will need to read on your own…from book or supplemental packet. • Geology Concepts • Layers of the earth • Rock Cycle (how each formed) • Sedimentary • Igneous • Metamorphic • Plate Tectonics • Earthquakes and volcanoes • Soil Properties and Formation

3. Soil Summary • Soil is formed via • Chemical, mechanical, or biological weathering • Soil is made of… • Gravel, Sand, Silt, and Clay • Organic material (humus) • Soil Horizons • O-organic matter • A-topsoil • B-subsoil • C-subsoil

4. Soil Characteristics • Texture and Composition • Soil ribbon/triangle • Nutrients • N-P-K • Porosity and water-holding capacity • Maintaining Soil Quality • Erosion and degradation

5. Human Nutrition • Food security: all/most people have access to enough food • Global unequal access to food…we do produce enough • Not everyone can afford to buy it • Food insecurity: all/most live with chronic hunger and poor nutrition…threatens lifestyle • Caused by poverty, war, corruption, bad weather (climate change)—interferes with transport/distribution • 1 in 6 people don’t get enough to eat (less-developed) • We increase food security by decreasing environmental and harmful effects of industrialized agriculture

6. Chronic undernutrition: can’t grow or buy enough to meet needs ~2200 kcal/day • 1 billion people worldwide! (less than 400 kcal) • 8.8 million people starve to death each year • Chronic malnutrition: diet deficient in protein or other nutrients; makes vulnerable to disease and hinders development • Low income/less developed, 3 billion people • Famine: severe shortage of food resulting in mass starvation, caused by catastrophic events • 18% mortality rate • Overnutrition: food intake exceeds need. Obesity epidemic—affluent countries. • 1.2 billion affected (300 million obese)

10. Nutrient Requirements • Macronutrients—protein, carbs, fats, fiber • Micronutrients—vitamins, minerals, elements • Agriculture has greatly improved the quality of the human diet since hunter-gatherer times • Produce more with industrialization but increase impact • Deficiencies result in stunted growth or diseases… • Vitamin A—blindness • Low iron—anemia • Iodine—goiter (thyroid problems)

11. What do we eat? Food. • We are considered “specialists”…eat few available edible plant species • 14 of 50,000 plant species feed 90% of the world • Corn, rice, wheat (48%) • Select mammal and fish species • Beef, veal, pork, lamb, chicken, turkey, duck • Meat consumption increases with affluence—majority of world vegetarian • Makes us vulnerable to climate changes…diet not diverse enough to deal with catastrophic change.

12. Where does our food come from? • Croplands • Industrialized or Subsistence Farming • Rangelands, Pastures, and Feedlots • Small farms vs. Factory farms • Fisheries and Aquaculture • Industrial fishing or Farmed fish

13. The Green Revolution • A shift occurred in farming from human/animal labor to machinery with selective breeding of crops, genetic modification, and increased use of fertilizer and water • Led to higher yielding crops and disease resistance • Increased use of fertilizer and improve irrigation technology • Monocultures of selectively-bred or GM crops • Ability to feed a growing population more effectively with less space

14. Negative Consequences • Mechanization: used machines instead of human/animal labor (fossil fuels), rely on monocultures (machines crop specific) • Irrigation: deplete groundwater reserves, cause waterlogging and salinization • Fertilizer: fossil fuels used to manufacture, runoff into waterways (algae growth) • Monocropping: plant and harvest crops at the same time, leads to soil erosion and vulnerability to pests • Pesticides: kill unwanted organisms, persistent in the environment, bioaccumulate, evolve resistance

15. Croplands • Industrialized—25% of all cropland supplies 80% of the worlds food. • Heavy equipment • Lots of money • Lots of fossil fuels • Lots of water used • Fertilizer and pesticides • Monocultures (single species) • High yield per acre of land **17% used for biofuel and 35% used to feed cattle

16. Croplands • Plantations • Grow cash crops—not for human consumption • Banana, palm oil, soy, sugarcane • Greenhouses and hydroponics • Cost more to produce, less impact on soil • Require large amounts of water and electricity

17. Croplands • Subsistence (small farming operations) • Small growing operations, most to feed families or small communities • 75% of land produces 20% of worlds food • Grow polycultures (multiple species) • “traditional” vs. “intensive” • Sun, humans, and animals vs. Sun, human, animals, fertilizer (manure), and water

18. GM Crops—the good • Increased yield and crop quality—resistant to pests and harsh conditions • Golden rice • Reduce need for pesticides • “Roundup ready” gene • Increased profits • More crops on same space

19. GM Crops—the concerns • Safe for human consumption? • Banned in the EU • Effect biodiversity • Elimination of natural plant varieties through accidental breeding • Regulation and Labeling • Currently not regulated in the US • Voluntary labeling • Organic= no GM • In the US… • Corn 63% • Soy 91% • Cotton 71% • 70% of food on store shelves contains something GM

20. Rangelands, Pastures, and Feedlots • 50% of meat comes from unfenced rangelands and pastures • 50% from Factory Farms • Veal calves, pigs, chickens and turkeys live in cages throughout their lives • Large environmental impact • Large demand for grain to feed animals

21. Rangelands, Pastures, and Feedlots • High-density farming (factory farms) • 56 BILLION animals are raised and slaughtered each year • Meat consumption rises with affluence • CAFO—Concentrated Animal Feeding Operation • Beef, poultry, dairy cow, hogs • 2500 hogs per building • 50,000 turkeys per building • Confined and allowed little room to move • Minimized land cost, efficient feeding • Antibiotics and supplements used due to high concentration • Perpetuates antibiotic resistant bacteria • Waste disposal concerns

22. Free-range • Animals can range part of the day outside • USDA defines as “spending part of the day outside” • No regulations on time, size, etc. • Used as a marketing term • Grass-fed • Mostly used in beef, raised on pastures, small farms • “finished” on grass, not fed a grain diet • Healthier, less fat, more expensive • Less impact • Cage-free • Not confined to cages, able to move around • Allowed to exhibit more normal behavior • Still live in highly concentrated areas, not “cruelty-free”

23. Fisheries and Aquaculture • Revisit commercial fishing practices and cause of fisheries collapse • Most major fisheries could collapse during this century • 2.6 billion people depend on fish in their diet • ~37% of wild fish caught turned into fish meal for aquaculture • Aquaculture • China world’s leader (carp, catfish, tilapia, shrimp, salmon) • Farmed fish kept in enclosures • Wastewater pumped into surrounding area • Bacteria, viruses and antibiotics • Escape and interbreed with native fish—some genetically modified

24. Concerns with Industrialized Agriculture • Had an enormous increase in food production since 1950s with green revolution • More food grown per acre, decreased amount of land used with a growing population • Protected biodiversity—less land converted to farms. • Industrializing Agriculture is the worst mistake in human history. • Why would we say this?

25. Cropland • Currently at upper limit of production • No way to increase total yield • Can’t irrigate, fertilize or genetically engineer more productivity • Meat Production • Requires large amounts of energy • Wastes create pollution • Erosion • Antibiotic use • Aquaculture • Depleting wild populations to feed farmed fish • 6 lb wild fish to make 2 lb farmed salmon • Increased toxins in farmed fish (bioaccumulate) • Waste production • Interbreed with wild fish • Spread invasive species

26. Problem: Agroecosystems • Ecosystem created by agricultural practices • characterized by low • Genetic diversity • Species diversity • Habitat diversity

27. Agroecosystems differ from natural ecosystems in five major ways: • Farming attempts to stop ecological succession • Species diversity is low because farmers usually practice monoculture. Monoculture tends to ß soil fertility • Farmers plant species (crops) in an orderly fashion - this can make pest control more difficult • Food chains are far more simple in agroecosystems because of pest control and other farming practices • Plowing is like no other natural disturbance - plowing can Ý erosion and cause more nutrient loss (which is replaced by fertilizer)

28. Problem: Topsoil Erosion and Soil Degradation • Soil moved by wind and water—largest cause • Wind problematic on dry flat land • Roots help anchor soil and store nutrients • Severe erosion leads to gullies forming • Lose fertile soil via farming, deforestation, overgrazing and vehicle use • Eroding soil faster than it forms **Causes loss of soil fertility and water pollution (sediment); pesticide residues enter water, alter chemical cycling

30. Problem: Desertification • Productive potential of topsoil falls by 10% or more due to drought, overgrazing, or deforestation • Moderate 10-25% decrease • Severe 26-50% decrease • Very Severe 51+% decrease • Only in extreme cases do new deserts form, usually borders of existing ones expand • Globally 70% of our dry lands are threatened (mostly in Africa) • Climate change is increasing drought conditions, which threaten food supplies

31. Problem: Irrigation • 70% of human water use is for irrigation • High concentration of salts dissolve into water from surrounding rock, as water evaporates into soil leaves behind salty residue (soil salinization) • Lowers growth and kills plants • Affects 25% of the cropland in the US • Waterlogging of soil, raises water table and kills plants • Depletes groundwater reservoirs

32. Problem: Air Pollution • Greenhouse gases (CO2, NO2, CH4) released through burning forests to clear the land (25% of total emissions) • Livestock generate 18% of all greenhouse gas emissions worldwide—mostly methane • This is equal to the emissions of 33 million cars!

33. Problem: Biodiversity Loss • Removing tropical rainforests to plant cash crops • Sugarcane, palm oil, soybeans • Release greenhouse gases into atmosphere faster than they can be removed • Our diet is limited…don’t eat a wide variety of plants • Limits our ability to deal with climate change

34. Plant Food Sources • 250,000 plant species Þ • 3000 tried as crops Þ • 300 grown for food Þ • 100 species used on large scale for food Þ • 15 to 20 species provide vast majority (90%) of man’s food needs • It takes about 16 pounds of grain to produce one pound of edible meat • And ~2500 gallons of water! • Largest crop volumes provided by: wheat, rice, corn, potatoes, barley • Wheat and rice supply ~60% of human caloric intake

35. Potatoes Barley Sweet Potato Cassava (source of tapioca) Grape Soybean Oats Sorghum Sugarcane Other Plant Food Sources • Peanut • Watermelon • Cabbage • Onion • Bean • Pea • Sunflower Seed • Mango • Millet • Banana • Tomato • Sugar Beet • Rye • Orange • Coconut • Cottonseed • Apple • Yam

36. Problem: Pesticides • Targets weeds, insects, fungi, microbes that threaten agriculture • Harm natural pest controls • Insecticide, fungicide, herbicide, rodenticide • Improves profits of the farmer • First developed from plant sources then moved to synthetic • DDT was the first • Use increased with green revolution, those used today 10-100 times more toxic • Vary in targets (broad/narrow spectrum) and persistence • Controlled by the EPA, USDA, FDA • 1947, 1972 Federal Insecticide, Fungicide, and Rodenticide Act • 1996 Food Protection Act

37. Kill unwanted pests that carry disease (rats, mosquitoes, Tse-Tse flies) Increase food supplies More food means food is less expensive Effective and fast-acting Newer pesticides are safer, more specific Reduces labor costs on farms Food looks better Agriculture is more profitable Accumulate in food chain Pests develop resistance – 500 species so far Resistance creates pesticide treadmill Estimates are $5-10 in damage done for $1 spent on pesticide Pesticide runoff Destroy bees - $200 million Threaten endangered species Affect egg shell of birds 5% actually reach pest ~20,000 human deaths/year Pesticides Pro and Con

38. Sustainable Agriculture • What can we do to make it better? • Improving Food Security • Pesticide Alternatives • Soil Conservation • Meat Consumption • Alternatives to Industrialized Practices

39. Improving Food Security • Government controlling prices (set upper limit) • Good for consumer, lower profit for farmer • Subsidize sustainable practices • In developing countries, give farmers tools to get started • Private aid organizations • Target hungry/malnourished children

40. Pesticide Alternatives • Polyculture instead of monoculture • Intercropping – alternate rows of crops that have different pests • Planting pest-repellent crops • Mulch to control weeds • Natural insect predators – ladybugs, preying mantis, birds • Rotating crops to disrupt insect cycles • Using Pheromones to attract insects to traps • Releasing sterilized insects • Integrated Pest Management (IPM) • Specific to local ecosystem • Difficult to implement

41. Soil • Erosion • Soil conservation—keep land covered with vegetation • Terrace sloped land (reduces runoff) • Contour planting (plant rows across slope) • Strip Cropping (alternate rows of crops) • Agroforestry (plant in orchard rows) • Windbreaks (reduce wind erosion) • Limit Plowing (no till/low till) • Identify erosion hotspots • Fertility (fertilizer alternatives) • Use organic fertilizers (manure, green manure, compost) • Crop rotation • Salinization • Reduce irrigation • Grow salt-tolerant crops • Desertification • Reduce destructive activities to soil and impacts on climate change

42. Meat Consumption • Aquaculture • Raise fish offshore in open ocean pens • Land-based, closed loop facilities (reduce pollution) • Eat lower on the fish food chain • Poultry and Livestock • Eat less • Eat lower on the animal food chain • Eliminate feedlots (pastures and rangelands) • More “free-range”

43. Alternatives to Industrialized Practices • Organic Agriculture • Non GMO • Pesticide and synthetic fertilizer free • Would be less expensive if environmental costs were included in the price of industrial farming products • Organic Foods Production Act 1990 • Use renewable forms of energy • Buy Local! Waste Less!