1. Predicting the Effects of Climate Change on Soil Loss You will learn how multiple factors contribute to soil erosion. You will analyze how climate change will impact soil sustainability. You will consider how natural process and humans influence soil sustainability.

2. The RUSLE has multiple factors that allow scientists to estimate annual soil loss for a particular site. Your job: Compare answers from your homework Prepare to explain your factor to the class List any unanswered questions your group has about your factor 3. The RUSLE has multiple factors that allow scientists to estimate annual soil loss for a particular site. R = rainfall and runoff erosivity K = soil erodibility LS = length slope (landscape) CP = cover management and support practices 4. Estimated average soil loss = R*K*LS*C*P The RUSLE equation can be used as a framework for considering how different factors work together. Copyright Andy Beecroft 5. Estimated average soil loss = R*K*LS*C*P The RUSLE equation can be used as a framework for considering how different factors work together. Copyright Andy Beecroft Keeping all other factors the same, if a farmer changes crop rotations such that contribution of the C factor decreases by one third, what would that do to the erosion rate (average soil loss)? 6. Estimated average soil loss = R*K*LS*C*P The RUSLE equation can be used as a framework for considering how different factors work together. Copyright Andy Beecroft If soil organic matter decreases such that K doubles, what could be done (besides adding more organic matter) to keep the erosion rate the same? 7. Activity: Human activity vs. natural processes Which of these two factors do you think has the most influence over Support practices Soil porosity Slope steepness Surface cover Rainfall intensity 8. Climate change also influences agriculture. Go to video 9. Climate change is predicted to impact precipitation during the summer growing season. What are the predicted changes for your region? Image source: Kenneth Kunkel, NOAA NCDC / Cooperative Institute for Climate and Satellites - NC 10. The relationship between precipitation and soil erosion is a complex system. Estimated average soil loss = R*K*LS*C*P 11. ? The relationship between precipitation and soil erosion is a complex system. 12. This diagram illustrates relationships between factors that influence erosion in agricultural systems. Modified from: Pruski, F. F., and M. A. Nearing, 2002, Climate-induced changes in erosion during the 21st century for eight U.S. locations, Water Resour. Res., 38(12), 1298, doi:10.1029/2001WR000493. + - - + + 13. The direction of the arrows indicates cause and effect relationships. (diagram modified from Pruski and Nearing, 2002) 14. For example, this arrow tells us that changes in precipitation cause changes in runoff. (diagram modified from Pruski and Nearing, 2002) 15. If it were pointing the other way, that would mean that changes in runoff cause changes in precipitation. This doesnt make much sense! (diagram modified from Pruski and Nearing, 2002) X 16. But, the direction of the arrows doesnt tell us how a factor impacts other factors. (diagram modified from Pruski and Nearing, 2002) 17. The + and signs indicate what type of relationship exists between the factors. (diagram modified from Pruski and Nearing, 2002) + - - + + + = positive relationship - = negative relationship 18. A positive relationship means that a change in one factor causes an effect on another factor in the same direction. (diagram modified from Pruski and Nearing, 2002) + + + 19. For example, this arrow indicates that an increase in precipitation causes an increase in runoff AND a decrease in precipitation causes a decrease in runoff (diagram modified from Pruski and Nearing, 2002) + 20. (diagram modified from Pruski and Nearing, 2002) - - A negative relationship means that a change in one factor causes an effect on another factor in the opposite direction. 21. (diagram modified from Pruski and Nearing, 2002) - For example, this arrow indicates that an increase in crop yield causes a decrease in erosion AND a decrease in crop yield causes an increase in erosion 22. So, we can use this diagram to describe relationships between factors that influence erosion in agricultural systems and predict how changes in one factor will influence other factors. (diagram modified from Pruski and Nearing, 2002) + - - + + 23. Models for Syracuse, Nebraska, predict that precipitation will decrease overall for the region. Erosion is also expected to decrease for wheat. Which pathway is most likely to be dominant for wheat? (diagram modified from Pruski and Nearing, 2002) + - - + + 24. The same models predict that, while precipitation decreases overall for the region, erosion is expected to increase for cornfields. Which pathway is most likely to be dominant for corn? (diagram modified from Pruski and Nearing, 2002) + - - + + 25. Based on these pathways, which crop do you think is more severely impacted by the decrease in precipitation? (diagram modified from Pruski and Nearing, 2002) + - - + + 26. In agricultural systems, humans also make decisions that can have big impacts. What are some ways in which humans influence agriculture?