1. Trends in Agricultural Chemical Concentrations for Three Sites with Corn Production Ashlynn Stillwell CE397: Statistics for Water Resources April 30, 2009

2. Outline Background Hypotheses Data & Results Current Conclusions Future Work Questions Ashlynn Stillwell CE397 | 4/30/2009

3. Background Policy mandates increase in biofuels Major feedstock for ethanol is corn Chemicals used to grow corn can pollute water Ashlynn Stillwell CE397 | 4/30/2009

4. Hypotheses 1.Corn production has increased over time. 2.Agricultural chemicals in water have increased over time. 3.There is a positive relationship between corn production and chemical concentrations. Ashlynn Stillwell CE397 | 4/30/2009

5. Sites 1 2 3 Ashlynn Stillwell CE397 | 4/30/2009

6. Corn Production Ashlynn Stillwell CE397 | 4/30/2009

7. Agricultural Chemicals Total nitrogen vs. time not statistically different from mean (R 2 = 0.028) Similar for phosphorus and atrazine (R 2 ≤ 0.3) Only one R 2 > 0.047 Ashlynn Stillwell CE397 | 4/30/2009

8. Corn-Chemical Relationship Ashlynn Stillwell CE397 | 4/30/2009

9. Corn-Chemical Regression Nitrogen = 5.64 - 1.6E-05*Corn (2.85) (-1.17) R 2 = 0.15 Se = 1.71 F = 1.37 Phosphorus = 0.61 - 2.4E-06*Corn (5.66) (-3.21) R 2 = 0.56 Se = 0.09 F = 10.3 Atrazine = 7.95 - 4E-05*Corn (2.22) (-1.80) R 2 = 0.45 Se = 2.02 F = 3.24 Ashlynn Stillwell CE397 | 4/30/2009

10. Current Conclusions 1.Corn production has increased at each of the three sites. 2.No statistically significant increase in chemical concentrations at three sites. 3.Small negative relationship between corn and chemicals, though not always significant. Ashlynn Stillwell CE397 | 4/30/2009

11. Future Work Perform statistical tests on difference between means Consider transforming data for better regression fit Use SPARROW to estimate nitrogen at sites Write report Ashlynn Stillwell CE397 | 4/30/2009

12. Questions Ashlynn Stillwell CE397 | 4/30/2009