1. MonthDayLectureActivityChap. Nov.21Ecosystems IIServices56 26Global C cycle56 Dec.3Thinking ecologically I 5Thinking ecologically II Eco. literacy 10Exam review 19Final examHere at 12:20 am

3. Agricultural production vs human populations

5. Factors driving increased food production New cultivars (breeds) of crops

6. Factors driving increased food production New cultivars (breeds) of crops Good cropland made better –Irrigation –Fertilizers –Pesticides –Mechanization

7. Factors driving increased food production New cultivars (breeds) of crops Good cropland made better –Irrigation –Fertilizers (N from fossil fuels) –Pesticides –Mechanization Marginal cropland put into cultivation –Irrigation –Fertilizers –Tillage

8. Energy use in agricultural production (in billions of Kcal) WhereTotal energy Energy per hectare Energy per capita Developed Nations 11085.9243.7 North America 5114.8379.6 Developing Nations 2210.532.6

9. Energy use in US corn production 1000 10,000 170019901950 Year Energy input (x 1000 Kcal/ha)

10. Food versus fuel Food energy Fuel energy Bulk production12 Edible production13 Shipping13 Processing13 Preparing12

11. Modern agriculture is subsidized by fossil fuels 1 unit food energy = 12 units fuel energy

12. Modern agriculture is subsidized by fossil fuels 1 unit food energy = 12 units fuel energy Think back to the trophic pyramid... Does negative energy transfer efficiency make sense?

13. Agricultural carbon cycle does not balance! 1 unit food energy = x g C, so took y g C out of the atmosphere 1 unit fuel energy = x g C, so put z g of C (CO2) into the atmosphere

14. Problems of modern agriculture Practice Problem addressed Problem created MechanizationLabor inefficiency erosion negative C balance energy dependency larger farms fewer farmers loss of farm culture

15. Problems of modern agriculture Practice Problem addressed Problem created Inorganic N fertilizers Crop yieldwater pollution increased pests greenhouse gas emissions (N 2 O) energy dependency

16. Problems of modern agriculture Practice Problem addressed Problem created PesticidesCrop lossnew pests resistant pests water and soil pollution human poisoning energy dependency

17. Problems of modern agriculture Practice Problem addressed Problem created Hybrids and genetically narrow crops Crop yieldpest problems loss of local adaptations chemical dependency dependency on external seed source

18. Solutions... Erosion from mechanical tillage –No till or low till systems –Perennial crops –Field layouts –Controlled irrigation

19. Solutions... Fertilizer pollution of water and atmosphere –Keep litter on the fields –Increased use of organic fertilizers –Type and timing of fertilizer application

20. Solutions... Pesticide resistant insects, pollution and human poisoning –Integrated pest management –“Smart” application of pesticides –Changes in consumer expectations –Genetic engineering of “natural” pesticide resistance

21. Solutions... Loss of genetic diversity –“Seed saving” –Crop diversification –Consumer demand

22. Solutions... Fossil fuel dependency –Buy local –Buy less processed foods –Eat lower on the food chain –Buy organic (?)