Phosphorus Index Based Management Douglas Beegle Dept. of Crop and Soil Sciences, Penn State University SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎

Why do we need a P Index? Why not just agronomic recommendations? NP2O5P2O5 K2OK2O Nitrogen Based Corn/Dairy Manure Regional P Balance ¼ ¾ Manure Crops Soil Animals Feed Eutrophication Nutrient flows in modern ag P Index ? Field P Balance NP2O5P2O5 K2OK2O Phosphorus Based Corn/Dairy Manure P Index SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎

SourceTransport Critical Source Area Indeks P Critical Source Area Management 1.Overlap of Source & Transport Indicators 2.Identify and manage the critical source areas 3.Evaluasi risiko lingkungan 4.Target dan Sumberdaya SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎

Mengelola Pencemaran Phosphorus Subsurface flow Tile flow Leaching Sources Transport Erosion Runoff N P K Hydrology Water Body SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎

Mehlich-3 soil P, mg/kg P loss, lb P 2 O 5 /A Uji Tanah vs. Kehilangan P R 2 = Sharpley, USDA-ARS Crop P Optimum P Threshold No recent P inputs SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎

Mehlich-3 soil P, mg/kg P loss, lb P 2 O 5 /A 75 kg P/ha TSP 112 kg P/ha swine slurry 150 kg P/ha poultry manure 75 kg P/ha TSP 112 kg P/ha swine slurry 150 kg P/ha poultry manure Uji Tanah vs. Kehilangan P (dengan pupuk P) Soil Only R 2 =0.80 For all data points R 2 = Sharpley, USDA-ARS SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎

Indeks P P Source Site Characteristics – Environmental Soil Test P Same soil test different interpretation Sampling Questions? P Saturation? – P Fertilizer Rate and Appl. Method – Organic P Rate and Appl. Method P Source Coefficient (PSC) – Direct availability of manure P to runoff – Based on WEP in manure SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎

Transport P oleh Erosi-Tanah Erosion reduced 95% Conventional till wheat Converted to no-till Total P mg/L Sharpley, USDA-ARS SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎

Zone Interaksi dengan Runoff  Location of applied P  Interaction with runoff P on surface Soil test at surface High P Saturation at surface P sat = P / Al + Fe Oxalate extr. or Mehlich 3 extr Mehlich 1 P (mg/kg) Depth (cm) Data from Mozaffari and Sims, 1994 Zone of interaction with runoff Plow depth SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎

Transpor P-larut dalam Runoff Conventional till wheat Algal-available P, mg/L Converted to no-till Sharpley, USDA-ARS SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎

Kehilangan P Larut oleh aliran bawah permukaan Kehilangan P ini sangat tergantung pada sifat-sifat tanah: – Hidrologi Piston flow Macro pores – Tekstur tanah – Kimia tanah (Fe, Al, Ca) – P loading/saturation – Drainage Buatan. Data from: Bolton et al., 1970 Culley and Bolton, 1983 SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎

Kehilangan P merupakan proses “Landscape” yg kompleks Subsurface flow Tile flow Leaching Sources Transport Erosion Runoff N P K Hydrology Water Body SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎

Indeks P = Phosphorus Index P Transport Site Characteristics 1.Erosi Tanah 2.Kelas Runoff 3.Potential Pencucian 1.Drainage bawah-permukaan 4.Contributing Distance 5.Modified Connectivity SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎

PA Phosphorus Index v 2.0 SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎

P loss, kg/ha P index value for the site kg P/ha TSP 112 kg P/ha swine slurry 150 kg P/ha poultry manure 75 kg P/ha TSP 112 kg P/ha swine slurry 150 kg P/ha poultry manure Indeks P mendeskripsikan Potensial kehilangan P Very high High MediumLow Sharpley, USDA-ARS R 2 =0.79 SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎

Indeks P = Phosphorus Index 1.Low P Index 1.N Based Management 2.Medium P Index 1.N Based Management 3.High P Index* 1.P Based: Crop removal 4.Very High P Index* 1.No P: Manure or Fertilizer High and Very High* –Modify Management based on P No or reduced manure Change time or method of application Conservation practices Buffers Etc. SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎

Rencana Manajemen Hara P Develop N based plan – Usually means excess P will be applied Use P Index to evaluate the N based plan – Is the risk of P loss acceptable Acceptable risk – N rate, excess P Unacceptable Risk – Modify N based plan, where necessary, to address P loss risk NP2O5P2O5 K2OK2O Nitrogen Based Corn/Dairy Manure NP2O5P2O5 K2OK2O Phosphorus Based Corn/Dairy Manure or SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎

Aplikasi Indeks P Eventually, all fields will have a high P index P Index is not the solution – Tool to buy time to solve problem – Minimizes negative impact of P while we come up with a sustainable solution – We need to get the system into better balance SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎

NRCS/EPA P Index Issues Proposed change in NRCS 590 Std. – P soil test only – No more P Index Easy to regulate Very strict limits Not supported by the science - Source/Transport Unrealistic for animal agriculture to comply with in short term Better soil P balance is a good long term goal – Withdrawn, under further review SUMBER: aesl.ces.uga.edu/MidAtlantic/2010/P%20Index-%20Doug%20Beegle.ppt‎