Urban Nutrient Management Research Update

1. Urban Nutrient Management Research Update Amy Shober, Ph.D. Soil & Water Science Department University of Florida Gulf Coast REC

2. Topics for Discussion Response of Landscape Grown Ornamentals to N Fertilization Nutrient Leaching from Simulated Mixed Landscapes During Establishment Nutrient Leaching from Established Mixed Landscapes.

3. Urban Landscapes • Complex system • Many land owners • Diverse vegetation • Soil issues • Many questions remain • How much fertilizer do we need? • What is the potential for nutrient loss?

4. Response of Landscape Grown Ornamentals to Nitrogen fertilization

5. Landscape Fertilization Florida Green Industries BMPs N Fertilizer Recommendations

6. Research Objective • How much N is needed to grow ornamentals in the landscape? • Research Objective • Determine plant response of selected ornamental plants to N fertilizer in the landscape.

7. Experimental Design Annuals, perennials, vines, groundcovers, and shrubs evaluated Raised beds with soil fill (no mulch) or field (shrubs only) Data collection over 2 years Polymer coated N fertilizer applied at 5 rates Other nutrients applied based on soil test

8. Nitrogen Fertilizer Rates

9. Data Collection & Analysis • Plant response parameters • Plant size index (cm3) = H × W1 × W2 • Quality rating (1-5) • SPAD (proxy for chlorophyll content) • Dry biomass (at harvest) • Tissue TKN (at harvest)

10. Plant Response to N Fertilizer 12 lb N 2 lb N 4 lb N 0 lb N

11. Regression Analysis Optimum N rate = 3.5-3.8 lb 1000 ft-2

12. Plant Quality Response 0 lb N/1000 ft2 12 lb N/1000 ft2

13. Plant Quality Response 12 lb N/1000 ft2 4 lb N/1000 ft2

14. Annuals Fertilizer Rates Based on plant growth and quality response of plants to slow-release N fertilizer in unmulched sandy fill soil.

15. Perennials Fertilizer Rates Based on plant growth and quality response of plants to slow-release N fertilizer in unmulched sandy fill soil.

16. Shrub Fertilizer Rates Based on plant growth and quality response of plants to slow-release N fertilizer in unmulched sandy fill soil.

17. Preliminary Conclusion We can reduce N applications by up to 60% if we fertilize to achieve acceptable quality plants compared with optimizing growth response. Most ornamental plants evaluated achieved acceptable quality when fertilized within current IFAS rates.

18. Continuing Research • Screening of additional species underway in field and fill soils. • Quantifying effect of N rate, timing, and application method N leaching.

19. Nutrient Leaching From Simulated Residential Landscapes

20. Nutrient Losses from Urban Landscapes • Nutrients from lawns & landscapes linked to coastal eutrophication • Focus of regulatory measures (e.g., fertilizer ordinances, bans, and blackouts)

21. Florida-Friendly Landscaping™ “Right Plant, Right Place” Florida Friendly design courtesy of Dr. Gail Hansen

22. Nutrient Leaching from Urban Landscapes • Will more nutrients be lost from landscapes with a higher proportion of ornamental plants?

23. Nutrient Leaching During Establishment of Simulated Residential Landscapes

24. Research Objective To determine the effect of vegetative cover type on the potential for nutrient losses during the establishment of landscape plants.

25. Landscape Plot Installation

26. Experimental Design • Liriope • Burford Holly • 24 Mixed Plots planted in Feb. 2008 • St. Augustine • Galphimia • Indian Hawthorn • Fertilizer & water applied based on IFAS recommendations • Drainage collected weekly and analyzed for inorganic N and P.

27. Drainage Depth P1 P2 P3 P4

28. Phosphorus Load a a b a b a a a b b Bars with different letters indicate a significant difference at α=0.05 using Tukey’s HSD Test.

29. Nitrate Loads a a b a a b a b a b Bars with different letters indicate a significant difference at α=0.05 using Tukey’s HSD Test.

30. Conclusion • Risk of nutrient leaching is higher for ornamental beds than for turf during plant establishment. • Landowners should prevent applications of nutrients and water to areas of the soil that do not contain plant roots during plant establishment.

31. Nutrient losses from Established mixed landscapes

32. Research Objective To determine the effects of plant cover (turf vs. woody ornamental) on nutrient leaching from established urban landscapes.

33. Materials and Methods • Three landscape treatments established in nine (11’×13’) drainage lysimeters (3 reps)

34. Materials and Methods Treatment 1 90% Turf 10% Ornamental 88.9 kg N ha-1 9.92 kg P ha-1 Treatment 2 75% Turf 25% Ornamental 142 kg N ha-1 18.0 kg P ha-1 Treatment 3 60% Turf 40% Ornamental 195 kg N ha-1 26.0 kg P ha-1

35. Materials and Methods • Daily subsamples →weekly flow-weighted sample • Leachate analyzed for: • Nitrate(+nitrite)-N (NOx) • Ammonium-N (NH4) • Total Kjeldahl N (TKN) • Dissolved P (DP) • Total P (TP)

36. Lysimeter Drainage

37. Cumulative Nutrient Loads Bars with different letters indicate a significant difference at α=0.05 using Tukey’s HSD Test.

38. Mass Balance (18 weeks)

39. Conclusion • Increasing the proportion of established woody ornamentals can improve nutrient use efficiency and decrease N losses in leachate from urban landscapes.

40. Acknowledgments • Cooperators • Vimala Nair • Kimberly Moore • Richard Beeson • Gary Knox • Geoff Denny • Craig Stanley • IFAS Statistics Consulting Service • Graduate students • Zhixuan Qin • Shawna Loper • Research Scientists • GittaShurberg • Nancy West • Christine Wiese • Tim Davis • Funding Agencies • Southwest FL WMD • Florida DACs

41. Questions?