Unit 4 – Agriculture

1. Ch.11 Unit 4 – Agriculture Thomas Robert Malthus: An English political economist, explained in simple terms the connection between population pressure and misery, which he defined as famine, poverty, disease and war. (from his 1798 book, An Essay on the Principle of Population.) • Food is necessary for human existence. • Human population, if not checked, tends to grow faster than the power in the earth to produce subsistence. • The effects of these two unequal powers must be kept equal. • Misery is the mechanism that balances human requirements and available resources.

2. Ch.11 Unit 4 – Agriculture The Human-Induced Biome: Agroecosystems • 11% of the land area in the world is used for agriculture (about the size of North & South America combined) • A rising % of NPP (Net Primary Production) is being converted from natural systems to support people

3. Ch.11 Unit 4 – Agriculture Food and Population Increase • As populations increase, the amount of land under cultivation MUST also increase • We usually see food shortages when pop’s reach their carrying capacity

4. Ch.11 Unit 4 – Agriculture How We Starve • Malnourishment: • Undernourishment: • Lack of Calories • < 1.2 x BMR • Lack of Nutrients • Can lead to: • Kwashiorkor • Can lead to: • Marasmus Both seem to be caused by energy-protein deficiency • Deficiency in certain nutrients micronutrients seem to lead to Kwashiorkor

5. Ch.11 Unit 4 – Agriculture • Global food production has stayed ahead of population growth. However: • One of six people in developing countries cannot grow or buy the food they need. • There will need to be a 40% increase in food over the next 20 years The root cause of hunger and malnutrition is poverty.

6. Ch.11 Unit 4 – Agriculture Overnutrition: • A 2005 Boston University study found that about 60% of American adults are overweight and 33% are obese (totaling 93%). • Americans spend $42 billion per year trying to lose weight. • $24 billion per year is needed to eliminate world hunger. Under Healthy Over- Obese

7. Ch.11 Unit 4 – Agriculture Crops: • ~150 plants have been used as crops • Only 14 are significant for world-wide food energy • Wheat Rice Maize • Potatoes Sweet Potatoes Sugar Cane • Sugar Beets Beans Soybeans • Barley Sorghum Coconut • Banana Manioc (yucca/cassava)

8. Ch.11 Unit 4 – Agriculture Agroecosystems • Industrialized agriculture • High-input monoculture • Traditional agriculture • Low-input polyculture • Rangeland • Unplanted grazing land • Plantation agriculture • Crops grown for export • Aquaculture • Farming in aquatic habitats • Pasture • Planted grazing land Found in mostly in tropical areas “Cash Crops” (coffee, tobacco, sugar cane, rubber trees) • 80% of the world’s food supply comes from industrial agriculture • Uses large amounts of fossil fuel energy, water, fertilizers, and pesticides Can produce higher yields than high-input monoculture

9. Ch.11 Unit 4 – Agriculture How are Agroecosystems different than natural ecosystems? • Try to stop ecological succession and keep the agroecosystem in an early successional state • Monoculture: Large areas planted with a single species • Crops are planted in neat rows • Farming greatly simplifies biological diversity • Plowing is unlike any natural soil disturbance • Genetic modification of crops. Leading to poor soil quality (N, P & K) Requiring irrigation Easy for pests and disease to spread Crops have low genetic variability Leading to greater soil erosion

10. Ch.11 Unit 4 – Agriculture The Green Revolution • After WWII (1950’s – 1980’s) programs were enacted aimed at feeding a booming population • Development of crops with… • higher yields (mostly due to better irrigation techniques) • better disease resistance • better ability to grow under poor conditions • Since 1978 the amount of irrigated land per person has declined due to: • Depletion of underground water supplies. • Inefficient irrigation methods. • Salt build-up. • Cost of irrigating crops

11. Ch.11 Unit 4 – Agriculture The GENE Revolution • To increase crop yields, we can mix the genes of similar types of organisms and mix the genes of different organisms (Genetic Engineering). Used to: • Transform genes from one major form of life to another • Develop hybrids faster than nature • Introduce the “terminator gene” • Has led to undesirable & unforeseen environmental effects: • Less pesticide needed for crops – • WOO HOO!! • But, every part of the plant including the edible tissues produce toxin not just the leaves that the caterpillars eat and would get sprayed with pesticide • Makes seeds from a crop sterile to: • Prevent genetically modified crops from spreading. • Protect the developer’s economic interest • (Farmers have to keep purchasing seeds) • Strawberry Polyploidy • Golden Rice • May create “superhybrids” that grow out of control or require much more fertilizer • Hexaploid (6n) • wild

12. Soils Ch.12 Unit 4 – Agriculture Undisturbed soils form layers/horizons (E) • Humus/leaf-litter • High organic content – very fertile • Mineral-rich • Clay • Weathered bedrock

13. Ch.12 Unit 4 – Agriculture Soil Texture Water/nutrient Retention: Particle size: Texture (when wet): • Sticky Erosion/ Sedimentation threat: • Gritty • Slippery

14. Ch.12 Unit 4 – Agriculture Soils Clearing natural vegetation + Tilling Soil ↓ Erosion of fertile topsoil ↓ Sedimentation of waterways • Annual Crop • Perennial grasses

15. Ch.12 Unit 4 – Agriculture Soils • Methods to help mitigate soil erosion: • No-till or minimum till seeding • Contour cropping / terracing • Leaving fields fallow • Rotating crops

16. Ch.12 Unit 4 – Agriculture Pesticides Only 10% of pesticide ingredients sprayed on American crops have been tested by the FDA

17. Ch.12 Unit 4 – Agriculture There are cultivation, biological, and ecological alternatives to conventional chemical pesticides. • Cultivate a more diverse crop • Provide homes for the pest enemies. • Implant genetic resistance. • Bring in natural enemies. • Use pheromones to lure pests into traps. • Use hormones to disrupt life cycles. Integrated Pest Management (IPM) • Uses a combination of alternative strategies and minimal chemical pesticides • Goal: to reduce crop damage to an economically-tolerable level

18. Ch.12 Unit 4 – Agriculture Animal Farming • Overgrazing occurs when the carrying capacity is exceeded. It can cause severe damage to lands. • Livestock production in developed countries is industrialized: • Feedlots are used to fatten up cattle before slaughter. • Most livestock are fed grain grown on cropland. (40% of grain grown worldwide) • Systems use a lot of energy and water and produce huge amounts of animal waste and methane gas.

19. Ch.12 Unit 4 – Agriculture Desertification About one-third of the world’s land has lost some of its productivity because of drought and human activities that reduce or degrade topsoil.

20. Unit 4 – Agriculture Biodiversity Loss Soil Air Pollution Human Health Water Loss and degradation of grasslands, forests, and wetlands Erosion Water waste Nitrates in drinking water Greenhouse gas emissions from fossil fuel use Aquifer depletion Loss of fertility Pesticide residues in drinking water, food, and air Salinization Increased runoff and flooding from cleared land Other air pollutants from fossil fuel use Waterlogging Desertification Fish kills from pesticide runoff Sediment pollution from erosion Contamination of drinking and swimming water with disease organisms from livestock wastes Greenhouse gas emissions of nitrous oxide from use of inorganic fertilizers Fish kills from pesticide runoff Killing wild predators to protect livestock Surface and groundwater pollution from pesticides and fertilizers Belching of the greenhouse gas methane by cattle Loss of genetic diversity of wild crop strains replaced by monoculture strains Bacterial contamination of meat Overfertilization of lakes and rivers from runoff of fertilizers, livestock wastes, and food processing wastes Return to question # 4 Pollution from pesticide sprays

21. 1. What is the predicted percent decrease in grain consumption from 1984 to 2015? 2. Using data from the graph explain why that decrease from # 1 is expected. 3. Why was there a huge increase in grain consumption from 1950 – 1984? Explain fully. 4. What are the environmental consequences of that massive increase in grain production? 5. What needs to be done in order to increase grain production in the future?

22. 1. What is the predicted percent decrease in grain consumption from 1984 to 2015? 28.5% 350 kg/yr - 250 kg/yr =100 kg/yr 100 kg/yr ÷ 350 kg/yr x 100 = 28.5%

23. 2. Using data from the graph explain why that decrease from # 1 is expected. Gross grain production is expected to increase by about 14% during this time, while population is expected to increase by 30%. This gap will cause the grain that is available to each person to decrease

24. 3. Why was there a huge increase in grain consumption from 1950 – 1984? Explain fully. • Green Revolution!! • Programs initiated to increase crop yields • A switch to industrialized, high-input, monoculture • Advances in machinery, irrigation, chemical fertilizer, and pesticide technology

25. 4. What are the environmental consequences of that massive increase in grain production? • Mention and explain degradation of • Biodiversity • Soil • Water • Air Consequences Chart

26. 5. What needs to be done in order to increase grain production in the future? • Convert land used for livestock to grains for human consumption • Increase crop yield • Genetically modified crops • Soil conservation techniques • Cultivation techniques