Phosphorus modeling and legacies in the Bay watershed Pete Kleinman, Tony Buda and Ray Bryant (USDA ARS)
Responding to the revised NRCS nutrient management standard: Validating and refining the P Index 2012 NRCS Conservation Innovation Grants Factory Brook Anderson Creek Allegheny Plateau Mahantango Creek ARS P modeling initiative Spring Creek PHYSIOGRAPHIC CONSITENCY - IN VALIDATON - Brushy IN P INDICES - IN Fork OUTCOMES Valley & Ridge Piedmont Conewago Creek Nanticoke River (Bucks Branch) Coastal Plain Upper Manokin River
1 68 135 202 269 336 403 470 537 604 671 738 805 872 939 1006 1073 1140 1207 1274 1341 1408 1475 1542 1609 1676 1743 1810 1877 1944 2011 2078 2145 2212 2279 2346 2413 2480 2547 2614 2681 2748 2815 2882 OLD Dissolved P, kg/ha NEW Dissolved P, kg/ha Changes to P routine in SWAT Days Old Routines New Routines 0.020 14 0.018 0.016 0.014 12 10 0.012 8 0.010 0.008 6 0.006 0.004 0.002 4 2 0.000 0 APLE run on a daily time step (from Vadas and White, USDA-ARS)
Center for Nutrient Solutions USEPA funded Courtesy Veith, USDA BMP Blanket P BMPs N BMPs
USDA-ARS multi-location project : Impacts of climate change on US agro-ecosystems Phase 1: Detecting past trends in climate, hydrology and water quality Precipitation Phase 2: Modeling climate change impacts on hydrology and water quality Boise, ID Temperature Tucson, AZ (high) (middle) (low) (high) (middle) (low) El Reno, OK Temple, TX Columbia, MO Oxford, MS University Park, PA Tifton, GA Garbrecht et al. (2013)
Living with legacy phosphorus: The somewhat obvious scenario UMES Research Farm Princess Anne, MD Allegheny Plateau Ridge & Valley Piedmont Coastal Plain
Soil test P summary Restricted to fields where the Maryland P Index was run (FIV > 150 only) Garrett Allegany (no data) Washington Frederick Carroll Baltimore Harford Cecil Mean Maryland P Fertility Index Value 150-200 200-250 250-300 300 350 350-400 Montgomery Howard (no data) Prince George s Charles Anne Arundel St. Mary s Calvert Kent Queen Anne s Talbot Dorchester Caroline Wicomico Worcester Somerset Courtesy J. McGrath, Univ. Maryland Average P FIV = 374
Manokin River Watershed
Manokin River Watershed
Field ditch 1 m deep 2 ha catchment Drainage ditch monitoring network Collection ditch 2.5 m deep 17 ha catchment H Flume on Field Ditch V-Notch Weir on Public Drainage Association
Total P Loss (kg/ha) 30 20 10 200 5 Sediment bound Dissolved Point sources as a major concern 0 1 2 3 5 6 7 8 Point sources 467 mg/kg 5 6 7 8 382 mg/k g 466 mg/kg Ditch 449 mg/kg Mehlich-3 P 3,113 mg/kg 447 mg/kg 3 421 mg/kg 2 1 Kleinman et al., 2007 (J. Soil Water Conserv.)
Infrastructure maintenance And this was installed with state subsidies as a BMP
P Loss (kg/ha) Precip (mm) Drainage losses from non-point sources Variability in flow determines annual load 0 500 1000 1500 3 0 20 10 0 2001 2003 2005 2002 2004 447 mg/kg 421 mg/kg 1 2 Kleinman et al., 2007 (J. Soil and Water Conserv.)
UMES draw-down study how long to lower soil test P? 100 75 Poultry litter P application rate (kg/ha) 50 25 0 Soil P requirement (0 kg P/yr) P-based N-based
Mehlich-3 soil P (mg/kg) Kleinman et al., 2010 (Canadian J. Soil Science) Legacy P No change after one decade 600 500 400 300 200 100 0 Lime 2000 2002 2005 2007 2009 3 2 1 0 Dissolved P in ditch flow (mg/l)
Depth below land surface (cm) Ray Bryant s gypsum curtains Mehlich-3 P P conc. Gypsum curtain Drainage ditch 0 50 100 150 300 mg kg -1 10 mg kg -1 5 mg kg -1 5 mg L -1 0.2 mg L -1 2 mg L -1 0.2 mg L -1 0.5 mg L -1 0.2 mg L -1 200 250
Ray Bryant s gypsum curtains Width 30cm Depth 1.5m berm
ChesapeakeStat.net, verified April 1, 2014 41591 44924
Mahantango Creek Watershed A rich history of hydrologic research WE-38 Klingerstown, PA Allegheny Plateau Ridge & Valley Piedmont WE-38 Watershed (7.3 km 2 ) Coastal Plain FD-36 (40 ha) Mattern (11 ha)
Legacy phosphorus: Not so obvious loads from little places Allegheny Plateau Mahantango Creek Experimental Watershed Klingerstown, PA Area = 7.2 km 2 Ridge & Valley Piedmont Coastal Plain Mattern watershed hillslope study
The Mattern watershed Well-drained Berks soil no fragipan Somewhat poorly drained Albrights soil fragipan
The fragipan and saturation excess runoff Poorly-drained soil fragipan Well-drained soil no fragipan soil matrix. Photo: S. Dadio prism face Photo: A. Buda Relatively impermeable (seasonal perched groundwater) Large interstices allow for rapid water infiltration
Runoff monitoring (2002-2004) Hillslope soil No fragipan, well drained Soil P saturation soil indicator only Mehlich-3 P - 144 mg/kg Psat = 17% Mehlich-3 P - 177 mg/kg Psat = 21% Mehlich-3 P - 78 mg/kg Psat = 9% Riparian soil Fragipan, poorly drained
Total P Soil P saturation soil indicator only Soil P measures were related to runoff P concentration (mg/l), not runoff load (kg/ha) 1 kg/ha/yr <1 kg/ha/yr Psat = 21% 8 kg/ha/yr I Psat = 17% Psat = 9% Buda et al. (2009) - JEQ
Soil P saturation soil indicator only <1 kg/ha/yr 1 kg/ha/yr 46 L 8 kg/ha/yr 92 L 4620 L Buda et al. (2009) - JEQ
The FD-36 Watershed Critical source area concept P-Index WE-38 watershed (7.3 km 2 ) Zones of runoff generation Regions with high soil test P FD-36 (40 ha) High Soil P (>100 ppm) Critical Source Areas High Soil P (>100 ppm) Courtesy Sharpley, USDA-ARS Critical Source Areas
The Mattern Watershed Identifying zones of saturation WE-38 watershed (7.3 km 2 ) August 2003 soil w/o fragipan soil w/ fragipan October 2003 soil w/o fragipan soil w/ fragipan Mattern (11 ha)
Extent of fragipan soil horizons in Mahantango Creek Percent of SSURGO soil map unit mapped as fragipan 1-10 10-20 20-30 30-40 40-50 50-60 60-70 70-80 80-90 90-100 Data courtesy of Sharon Waltman, USDA NRCS
Need for improved mapping to identify where runoff is most likely to occur Lessons from the Mattern watershed: SSURGO No fragipan Fragipan Order 1 No fragipan Fragipan Wet boot survey Saturated
Mattern fragipan prediction for lower landscape positions Berks Hartleton Leck Kill Leck Kill Albrights fragipan Berks Probability of a restrictive layer (%) Courtesy Drohan, Penn State 1-25 25-50 50-75 75-100
Validation efforts are ongoing Ground penetrating radar (GPR) Example transect showing GPR reflectance Base of the plow layer Restrictive layer Courtesy Drohan, Penn State
Improved critical source area mapping Restrictive Prone to runoff layer
Thanks