1. The cause and effect of soil variability in the Ecuadorian Andes

2. Study area

3. The potato-pasture system in Carchi Fertile volcanic ash soils Potato-pasture rotation Seasonality almost absent Market oriented production Intensive use of external inputs

4. Research question Provide accurate information about the economic and environmental consequences of agricultural systems and policies, considering the complex interactions between bio-physical processes and farm management decisions

5. The Tradeoff Analysis Model Field evaluation Crop/management decisions Management evaluationTradeoff analysis Scenario definition

6. Scale Number of observations Soil survey 100625 2,500 10,000 62,500 250,000

7. Causes of soil variability Parent material Topography Tillage erosion Land management Climate

8. Cause 1. Parent material

9. Results R2R2

10. Cause 2. Topography

11. Results R2R2

12. Cause 3. Tillage erosion

14. Tillage erosion = f(distance, topography) No tillage erosion Strong tillage erosion

15. Results R2R2

16. Cause 4. Land management

18. Results R2R2

19. Cause 5. Climate

20. Results R2R2

21. Detailed soil survey

22. Simulation Inherent productivity Carbofuran use Potato/dairy ratio Carbofuran leaching Tillage erosion

23. Effect 1

24. Carbofuran leaching Low High

25. Carbofuran leaching Low High

26. Carbofuran leaching Low High

27. Carbofuran leaching Low High

28. Carbofuran leaching Low High

29. Carbofuran leaching Low High

30. Carbofuran leaching Low High

31. Carbofuran leaching Low High

32. Carbofuran leaching Low High

33. Effects 2 Causes of variation: 62 % soil variation 38 % price variation

34. Effects 3

35. Repercusions on soil variability

37. Conclusions

38. Current research activities - Kenya -

39. Current research activities - Senegal - CENTURY

40. Current research activities - USA - Consortium for agricultural soils mitigation of greenhouse gases

41. www.tradeoffs.nl www.tradeoffs.montana.nl