1. Erosion Control with Polyacrylamide for Highly Disturbed Upland Soils Nazifi Rabiou, Graduate Research Assistant Dr. Clark J. Gantzer, Advisor Soil & Atmospheric Sciences University of Missouri

2. Acknowledgments Advisor, Committee Members, and Cliff Mongler Niger Government and the Fulbright Program Water Resource Research grant support

3. Outline of the Presentation Krilium water soluble polymers use Why is Polyacrylamide being on focus as an alternative soil conditioner and recent research on PAM The ongoing research on guidelines development for use of PAM

4. 1948: Research started to find a synthetic soil conditioner 1951: Krilium

5. Enhances Flocculation Compared effect of PAM on water turbidity: aft PAM application and Control

6. Why is Polyacrylamide of Interest? Results from research on PAM show Effective erosion control Sustained water infiltration rates Reduce soil surface sealing Reduced cost of erosion control Potential use for prairie restoration and construction sites

7. Upland Erosion Control: PAM Research at MU PAM application methods were studied to determine and compare effectiveness of application methods: Infiltration, runoff runoff and erosion data on Mexico clay soil with PAM rate of ~10kg/ha resulted in: 62% of runoff with PAM vs. 72% without PAM 46% of sediment reduction with PAM compared to untreated Thompson et al. 2001. ASAE Annual International Meeting

8. Devaney et al. 2002. ASAE Annual International Meeting PAM Research at MU Erosion from different PAM applications methods after 1.25 hr of simulated rainfall at 6.4 cm/h.

9. PAM Research at MU Devaney et al. 2002. ASAE Annual International Meeting PAM Reduces Erosion Erosion from different PAM applications methods after 1.25 hr of simulated rainfall at 6.4 cm/h.

10. Devaney et al. 2002. ASAE Annual International Meeting PAM Research at MU PAM treatments have mixed Infiltration effects Runoff after 1.25 hr of simulated rainfall at 6.4 cm/h.

11. Other Research on PAM Costal plain of Israel (Smith et al. 1990) National Soil Erosion lab (Flanagan et al., 2002)

12. PAM Reduces Soil Erosion Smith et al. 1990. SSSAJ

13. Polyacrylamide (PAM) PAM increases soil cohesion & enhances the aggregates by binding particles together

14. PAM & GypsControlPAM PAM - Soil Erosion

15. PAM Increases Final Infiltration Rate Smith et al. 1990. SSSAJ

16. Raindrop & Soil Detachment after Ellison 1947

17. PAM Reduces surface sealing

18. Reduced Cost Application of PAM at 80 kg ha -1 costs ~$400 ha -1 (Green and Stott, 2000) Application of traditional mulch is ~$1,600 and $400 (Less than the cost of mulch a traditional method of erosion control (Chaudhary and Flanagan, 1998)

19. PAM for Prairie Restoration Prairie restorations sites are often subjected to frequent tilling a full year before planting to reduce weed seed competition. This has a beneficial effect of reducing weed competition BUT at a high cost because the soil is left totally unprotected from erosion. Eroded sediments move to stream causing degradation of aquatic habitats.

20. PAM for Prairie Restoration PAM amendments are well suited to reduce soil erodibility during this period of soil preparation Springtime erosion for a prairie restoration site at the Prairie Fork Conservation Area. Gantzer 2000.

21. PAM can help prevent such PFCA gully erosion Gully created from Dec. 2003- to Apr. 2004. Prairie Foundation Site in preparation for prairie restoration. Gantzer, 2004

22. PAM For Construction Sites Erosion Control Major problem associated with erosion on a construction: Movement of soil off the site and its consequent pollution of receiving rivers, streams and lakes In Missouri 70 to 90 percent of the eroded soil (sediment) that reaches any type of channel is transported to the state’s water resource (http://www.dnr.mo.gov/wpscd/wpcp/field-guide/fg02_erosion.pdf.)

23. Construction Site Erosion -East Broadway, Columbia, MO Soil Conservation Class 2003

25. Construction Sites Disturbing thousands of hectares results in severe erosion due to steep slopes, bare soil and compaction High costs over short times PAM application reduced soil erosion by 83% and decreased runoff by 16% ( Roa-Espinoza et al, 2000) PAM can provide environmental benefits an also reduce management costs.

26. Reduction of Nutrient and Pesticides from Eroded Sediments in Water Effluent containing excess nutrients promotes algal blooms in surface waters. PAM has been shown in USDA-ARS work in Idaho, to be capable of reducing nutrient loss from surface waters (Sojka & Entry, 2001)

27. PAM may be Effective on Steep Slopes Large scale land excavation that leave great areas of soil, subsoil and tailing materials exposed poses erosion and water contamination risks

28. Ongoing MS Research Rationale - factors that affect PAM’s longevity in soil remain largely unanswered Rationale - factors that affect PAM’s longevity in soil remain largely unanswered Objectives - to study different PAM application methods to learn about the longevity of its effectiveness in reducing erodibility, and maintaining infiltration Objectives - to study different PAM application methods to learn about the longevity of its effectiveness in reducing erodibility, and maintaining infiltration Methods - to evaluate sieved repacked Mexico Ap soil in 0.3- by 0.3-m simulated rainfall box Methods - to evaluate sieved repacked Mexico Ap soil in 0.3- by 0.3-m simulated rainfall box

29. Rationale Construction sites soil are susceptible to erosion before re-establishment of vegetation Repair of eroded slopes is costly Sedimentation and water pollution result in environmental and economic losses to the general public and the contractor

30. Rainfall Simulation Miller, W.P. 1987. A solenoid-operated, variable intensity rainfall simulator. Soil Sci. Soc. Am. J. 51:832-834.

31. Rainfall Simulation Miller, W.P. 1987. A solenoid-operated, variable intensity rainfall simulator. Soil Sci. Soc. Am. J. 51:832-834. A rainfall simulator is being used with this study. Coefficients of uniformity for a 1 m 2 plot under a single nozzle are 90 to 95. Kinetic energy of the rainfall, determined from drop size distributions, is about 23 J m -1 mm -2, which is within the range for natural rainfall.

32. Rain Simulator Nozzle A Spraying Systems Fulljet 30 Wide Square nozzle with a spray angle of 104º used A precision pressure regulator provides 28 kPa water pressure to provide a water discharge of 7 L min -1 to provide a rain rate of 70 mm h -1

33. Rainfall Simulator gauges 49 small rainfall collectors 10cm by 10cm to evaluate the the rainfall variation with, time space and pressure.

34. Problems with Spatial Variability of Rainfall Intensity 3 nozzles 50WSQ type were evaluated Surface curve of the rain intensity from 49 rain collectors

35. Problems with Spatial Variability of Rainfall Intensity 3 nozzles 50WSQ type were evaluated Surface curve of the rain intensity from 49 rain collectors

36. Soil Bed Positioning The work is being conducted at the Biological Engineering Hydraulic Lab The test bed is located 3m directly below at wide angle nozzle The bed is set at a 5% slope

37. Soil Test Bed The test bed is 0.3 by 03 m The Bed has 15 2-mm holes for drainage A screen is placed on the bed and then a 50-mm layer of coarse sand is filled over which 10-mm deep layer of 10-mm sieved Mexico soil is packed to 1.3 Mg m -3

38. 30 WSQ Nozzle Calibration New pressure regulator to set and monitor the desired water supply

39. Rain Intensity Variation with Time Rainfall intensity for 5 min periods Statistical analysis shows rainfall intensity is highly variable with time (P<0.001).

40. Ongoing Experimental Design Factorial Experiment 12 treatments Factor A: number of applications ( 1, 2 3) Factor B : amount of PAM applied (20, 40. 60 and 80kg/ha)

41. Expected Results Gain insight on: Longevity of PAM application protection Longevity of PAM application protection Guidelines Development for PAM application in soil erosion control Guidelines Development for PAM application in soil erosion control Insight on stabilizing effect with Gypsum combination. Insight on stabilizing effect with Gypsum combination.

42. Summary Why is PAM being on focus as an alternative soil conditioner Background of the water soluble polymers use Recent research on PAM at MU The ongoing research on guidelines development for use of PAM

43. Questions? www.imb.org/southern-africa/ images/Hgiraffe_5.jpg