1. Agriculture Chapters 9

2. US Farming  3% of workforce  Family Farm vs Corporate Farm  Subsidies  To grow (Commodity)  Not to grow (Conservation)  Disaster  Farm Subsidies Database Farm Subsidies Database Farm Subsidies Database

3. Top 10 World’s Food Crops 2010 : By Quantity:  Sugar Cane  Corn  Rice  Wheat  Potatoes  Soy  Cassava  Sugar Beet  Tomatoes  Barley By Value:  *Rice  *Wheat (#2 US)  *Soy (#3 US)  Tomatoes  Sugar Cane  Corn (#1 US)  Potatoes  Grapes  Apples  Bananas http://faostat.fao.org/site/339/default.aspx

4. Cassava Root, native to South America. Leaves are edible as well Sorghum, used as a grain for making flatbreads Barley, an edible grain used as fodder and for alcohol production

5. Manioc Sugar beet 54% of US sugar SorghumSoybean

6. Crops  Cash/Commodity: for selling & trading large scale  Food Crops  Includes coffee, tea  Non food:  Fiber: cotton, hemp  Biofuel: switchgrass, corn  Pharmaceutical: tobacco  Biopolymer: latex, corn  Forage: for animal feed.  Alfalfa, sorghum, hay, corn  Subsistence: used directly by farmer for food/feed

7. Food-Fuel Connection  Use of food crop land to grow plants for biofuels: Biodiesel, ethanol  Corn, switchgrass, soy, sorghum  Cost of fuel for farm equipment, delivery, processing  Petroleum used to make pesticides & fertilizers.

8.  Monocultures:  One type of crop (corn field, sod, etc)  Pests  Degrades Soil Fertility  Use of Pesticides Iowa Corn field: Corn Borer Heaven!

9. Soil Horizons

10.  ‘O’ : Organic Layer; decaying matter, leaf litter  ‘A’ : Topsoil. Darker than O, most nutrient rich. Lots of organic matter  ‘E’ : Minerals leach out (leave) here and accumulate below  ‘B’ : light color, dense, low organic content  ‘C’ : transition between soil & parent rock  ‘R’ : Parent material, bedrock

12. Changes in Soil  Erosion.  Fertile Soil directly exposed to the elements.  Not rotating crops  Poor Tilling practices  Slash and Burn (swidden) Agriculture: clearing areas of rainforest through controlled burning.  Ash fertilizes soil, pests are removed.  Soil quality declines over time, then new area is selected.

13. Erosion due to not rotating crops; most damage occurred within two years.

14. Erosion (cont.)  Increased Sedimentation downstream  Increases toxins in water (heavy metals, nitrates, ammonia)  Increases Eutrophication  Leads to Biomagnificaton:  Dust Bowl of the 1930s  Video Clip Video Clip Video Clip

15. Salinizationof soil  Increased Soil Salinity  Aquifers w/dissolved minerals used for irrigation  Water evaporates, leaves concentrated salt behind  To Prevent:  Low water crops  Drip irrigation  Use water w/low salt content  To mitigate  Allow rain/irrigation to flush out salt  Use salt-tolerant crops  Strip Cropping

16.  Soil Sustainability  Contour Plowing: Land is plowed along its contours, perpendicular to slope. Reduces erosion through runoff.  Terracing: decrease runoff  No-Till Agriculture: No plowing. Herbicides are used to manage (not eliminate) weeds

17. Example of No-Till Agriculture. Sunflowers are planted in the leftover wheat stubble from previous season. Stubble acts as mulch, keeping moisture in.

19. Rice Terraces in the Philippines 2004 http://en.wikipedia.org/wiki/Terrace_(agriculture)

20. Terraced Rice Fields in Yunnan Province, China 2003

21. Desertification  About 1/3 of land should be desert  ~43% actually is. Occurs in poorest countries  Causes:  Poor farming & forestry practices  Conversion of ranges to cropland in marginal areas  Poisoning of Soil  Climate change

23.  Prevention Desertification:  Monitoring symptoms  Proper soil, forest conservation  Irrigation  Use of Windbreaks

24. Example of a Windbreak

25. Strip Cropping  Planting crop in every other row; leave the other row permanently fallow  Helps stop erosion by creating a natural dam  Helps pull salt away from crops through capillary action  Useful on steep slopes

26. Area of strip cropping in Wisconsin http://en.wikipedia.org/wiki/File:Strip_farming_in_Wisconsin,_USA,_1957.jpg

27. Grazing  Feedlots as Point-source pollution  Ground compaction  Reductions in Native Vegetation  Competition with native herbivores  Overgrazing  Decreases biodiversity  Increases erosion