Powerpoint for Guided Lecture

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 doesn’t make
much sense!
(diagram modified from Pruski and Nearing, 2002)
X

16. But, the direction of the arrows doesn’t 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?