1. Native Grasses for Erosion Control Nick Dudley - HARC and Dr. Joe DeFrank UH-Manoa in Hawaiian Tree Farms

2. Hawaiian Grasses • Emoloa (Erogrostis variablis) • Pili (Heteropogon contours)

5. Site Prep at Poamoho • Site sprayed with 2% Roundup solution • Overhead irrigation system installed • 6 weeks later, • Site sprayed with 1% Roundup & Garlon • 3 weeks later, 2nd application • 1% Roundup & Garlon

7. Site Prep at Poamoho • Site sprayed with 2% Roundup solution • Overhead irrigation system installed • 6 weeks later, • Site sprayed with 1% Roundup & Garlon • 3 weeks later, 2nd application • 1% Roundup & Garlon

9. Site Prep at Poamoho • Site sprayed with 2% Roundup solution • Overhead irrigation system installed • 6 weeks later, • Site sprayed with 1% Roundup & Garlon • 3 weeks later, 2nd application • 1% Roundup & Garlon

11. Site Prep at Poamoho • After additional 6 weeks, • 1% Roundup solution was sprayed • 1 month later, • Final preplant herbicide spray, • Roundup @ 1.0 lb ai/acre • Ronstar 50wp a@ 2.0 lb ai/acre

13. Transplanting • 2 weeks after final herbicide spray, • Koa seedling transplanted • Spacing 6ft within row • Hawaiian grass seedlings transplanted • Spacing 2 ft within row

18. Universal Soil Loss Equation(USLE) • The soil loss equation is : • A = RKLSCP • where • A = soil loss (tons/acre/yr) • R = rainfall factor • K = soil erodibility factor

19. (USLE) continued • L = slope-length factor • S = slope- gradient factor • = combined LS value • C = cover and management factor • P = erosion control practice factor

20. Estimated soil loss factors for Poamoho • R = 330 • K = 0.17 • LS values = .287 • P = .75

21. Estimated soil loss factors for Poamoho • C values: • Bareground = 1.0 • Control = .07 • Pili grass = .003 • Emoloa grass = .035

23. Estimated soil loss for Poamoho • Ground cover (tons/a/yr) • Bareground 12.1 • Control (40% weed cover) .85 • Pili grass .036 • Emoloa Grass .42

27. Timed hand weeding at 60 days • Treatments Est. time to weed (a/hr) • Control 11 hours • Pili grass 3.7 hours • Emoloa grass 11.8 hours

31. PILI GRASS MOW AND BLOW - ON SITE PRODUCTION OF WEED SUPRESSING ORGANIC MULCH • UPRIGHT GROWTH IDEAL FOR MULCHING • DOES NOT ROOT AT NODES • REGROWS FROM STUMPS • BUNCH TYPE GROWTH FORM - REDUCE CROP COMP.

35. DEMONSTRATION PLOT ON AUGUST 28, 2002 90 DAYS AFTER PLANTING

39. Summary • Native grass species and establishment methods have been identified for minimum tillage koa reforestation system • Pili grass has lowest estimated soil loss • Pili grass required least amount of time to hand weed

40. Summary(cont.) • Emoloa required the greatest time to hand weed • Both native grasses provided better soil protect than the control treatment • The mow & blow system can produce weed supressing organic mulch on-site

41. Acknowledgements • Environmental Protection Agency, Region IX • Hawaii State Department of Health, Clean Water Branch • Glenn Sakamoto, Station manager, PMC/NRCS - Molokai