1. Rao Mylavarapu Soil & Water Science Department, IFAS University of Florida

2. Optimum Yield or Quality ‘Optimum’ should ideally refer to economically and environmentally sustainable returns ‘Optimum’ should ideally refer to economically and environmentally sustainable returns Existing approaches have been predominantly based on economics Existing approaches have been predominantly based on economics Profit

3.  No Soil Testing  Always Fertilize  Luxury Consumption  Pollution Potential Hi  Treats soil as a bank  Calibrated Soil Test  Fertilizer amounts adjusted for soil contribution  Based on plant need, not plant uptake  Pollution Potential Low  Fertilize the plant not the soil

4. Soil Categories & Extractants for Florida Acid soils - Mehlich-1 (dilute double acid) Acid soils - Mehlich-1 (dilute double acid) -P, K, Ca, Mg, Cu, Zn, Mn Calcareous soils (pH > 7.4) - AB-DTPA (Ammonium Bicarbonate-DTPA) Calcareous soils (pH > 7.4) - AB-DTPA (Ammonium Bicarbonate-DTPA) -P only Organic soils Organic soils -Water extraction for phosphorus -Acetic Acid for K, Mg, Ca, Na, Si

6. Field Calibration AB-DTPA extraction procedure for calcareous soils needs to be replaced urgently AB-DTPA extraction procedure for calcareous soils needs to be replaced urgently -poor field calibration with the procedure severely limits its applicability limits its applicability -extremely high carbonate levels make calibration difficult -background P concentration higher than the critical limit -both commercial and urban horticultural operations lack a valid soil test

7. Soil and plant diagnostics are complementary and serve different purposes Soil and plant diagnostics are complementary and serve different purposes Tissue test does not completely replace a soil test Tissue test does not completely replace a soil test Plant analysis is effective in monitoring in-season nutrient needs, especially of perennial crops Plant analysis is effective in monitoring in-season nutrient needs, especially of perennial crops The tissue tests confirm suspected nutrient deficiency symptoms, reveal hidden hunger and verify toxicities The tissue tests confirm suspected nutrient deficiency symptoms, reveal hidden hunger and verify toxicities Nutrient deficiencies corrected through foliar applications, although not always effective Nutrient deficiencies corrected through foliar applications, although not always effective

8. Leaf diagnosis shows nutrient status at the time of sampling reflecting soil fertility status Leaf diagnosis shows nutrient status at the time of sampling reflecting soil fertility status Soil fertility status in turn is also determined by temperature, water, management factors, nutrient balance, etc Soil fertility status in turn is also determined by temperature, water, management factors, nutrient balance, etc Leaf analysis has to be integrated with soil analysis for confirming the deficiency, sufficiency or toxicity Leaf analysis has to be integrated with soil analysis for confirming the deficiency, sufficiency or toxicity

9. Complementary Soil & Tissue Testing Two such new tests have been developed and implemented Two such new tests have been developed and implemented - for Bahia pastures -for commercial Citrus In both tests, phosphorus requirement and deficiency confirmation is determined by a combination of both soil and a plant tissue test In both tests, phosphorus requirement and deficiency confirmation is determined by a combination of both soil and a plant tissue test Potential for a new protocol for Blueberries Potential for a new protocol for Blueberries

11. Plant Sap Analysis

13. NIR Spectrophotometry Technique provides routine soil analysis routine soil analysis decision support decision support soil property classification soil property classification soil survey and mapping soil survey and mapping precision agriculture precision agriculture diagnosis of soil problems diagnosis of soil problems contaminated site characterization contaminated site characterization input data for models input data for models

15. Why Replace Wet Chemistry?

16. Soil Test Laboratory Techniques

17. Reflectance Method and Processing ReflectanceMeasurement Signal Processing Statistical Analysis Validation Calibration Interpretation & Recommendation

18. Previous Work

20. Water

25. Predicted & Validated Soil Properties

26. Study 3 (on-going) A sample set consisting of 1,000 soil and corresponding 1,000 tissue samples is being collected from through out the state A sample set consisting of 1,000 soil and corresponding 1,000 tissue samples is being collected from through out the state Commodities targeted- forages, vegetables, peanuts, citrus (Ridge, Flatwoods and Indian River) Commodities targeted- forages, vegetables, peanuts, citrus (Ridge, Flatwoods and Indian River) Soil and leaf tissue reflectances will be correlated Soil and leaf tissue reflectances will be correlated A subset of soil samples was used to determine the influence of multiple moisture levels A subset of soil samples was used to determine the influence of multiple moisture levels Soil texture will also be determined for a subset of soil samples Soil texture will also be determined for a subset of soil samples Mylavarapu, R.S., Schumann, A.W., Obreza, T.A., Cornejo, C. 2007. Rapid Soil & Tissue Analysis Techniques Using Near Infrared Reflectance Spectroscopy. FDACS Project 61580, Annual Progress Report.

27. Results PLSR for P in DRY and MOIST soils samples respectively –Moist refers to samples as they arrive from the field –Dry samples are oven dry Dry Moist

31. Part A: Transport Potential Due to Site and Transport Characteristics Site and Transport Characteristics Phosphorus Transport Rating Value Soil ErosionNo Surface Outlet 0 <5T/A a 1 5-10 T/A 2 10-15 T/A 4 >15 T/A 8 Runoff PotentialVery Low 0 Low 1 Medium 2 High 4 Very High 8 Leaching PotentialVery Low 0 Low 1 Medium 2 High 4 Very High 8 Potential To Reach Water Body Very Low 0 Low 1 Medium 2 High 4 Total for Part A: Site and Transport b Part B: Transport Potential Due to Phosphorus Source Management Phosphorus Source Management Phosphorus Loss Rating Value Fertility Index Value Soil Fertility Index x 0.025 ( _____ ppm P x 2 x 0.025) c P Application Source and Rate d 0.05 x ( _____ lbs P 2 O 5 ) for fertilizer, manure or compost 0.015 x ( _____ lbs P 2 O 5 ) for biosolids 0.10 x ( _____ lbs P 2 O 5 ) for waste water Application Method No Surface Outlet Or Solids incorporated immediately or injected Applied via irrigation Or Solids incorporated within 1 day of application Solids incorporated within 5 days of application e Solids not incorporated within 5 days of application 0246 Waste Water Application 0.20 x _____ acre inches/year Total for Part B: Phosphorus Source Multiply Part A x Part B THEFLORIDAPINDEXTHEFLORIDAPINDEX

34. Priorities Determine the feasibility of complementary soil and tissue analyses for phosphorus management for perennial crops and landscape plants and grasses Determine the feasibility of complementary soil and tissue analyses for phosphorus management for perennial crops and landscape plants and grasses Integrate recommendations for irrigation management with nutrient recommendations for commercial horticultural crops Integrate recommendations for irrigation management with nutrient recommendations for commercial horticultural crops Further develop VNIR techniques and continue field calibration for wider diagnostic applications Further develop VNIR techniques and continue field calibration for wider diagnostic applications Develop newer diagnostic techniques for environmental impact assessment Develop newer diagnostic techniques for environmental impact assessment

35. Thank You! raom@ufl.edu