Phosphorus modeling and legacies in the Bay watershed. Pete Kleinman, Tony Buda and Ray Bryant (USDA ARS)

Transcription

1 Phosphorus modeling and legacies in the Bay watershed Pete Kleinman, Tony Buda and Ray Bryant (USDA ARS)

2 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

3 OLD Dissolved P, kg/ha NEW Dissolved P, kg/ha Changes to P routine in SWAT Days Old Routines New Routines APLE run on a daily time step (from Vadas and White, USDA-ARS)

4 Center for Nutrient Solutions USEPA funded Courtesy Veith, USDA BMP Blanket P BMPs N BMPs

5 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)

6 Living with legacy phosphorus: The somewhat obvious scenario UMES Research Farm Princess Anne, MD Allegheny Plateau Ridge & Valley Piedmont Coastal Plain

7 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 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

8 Manokin River Watershed

9 Manokin River Watershed

10 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

11 Total P Loss (kg/ha) Sediment bound Dissolved Point sources as a major concern Point sources 467 mg/kg mg/k g 466 mg/kg Ditch 449 mg/kg Mehlich-3 P 3,113 mg/kg 447 mg/kg mg/kg 2 1 Kleinman et al., 2007 (J. Soil Water Conserv.)

12 Infrastructure maintenance And this was installed with state subsidies as a BMP

13 P Loss (kg/ha) Precip (mm) Drainage losses from non-point sources Variability in flow determines annual load mg/kg 421 mg/kg 1 2 Kleinman et al., 2007 (J. Soil and Water Conserv.)

14 UMES draw-down study how long to lower soil test P? Poultry litter P application rate (kg/ha) Soil P requirement (0 kg P/yr) P-based N-based

15 Mehlich-3 soil P (mg/kg) Kleinman et al., 2010 (Canadian J. Soil Science) Legacy P No change after one decade Lime Dissolved P in ditch flow (mg/l)

16 Depth below land surface (cm) Ray Bryant s gypsum curtains Mehlich-3 P P conc. Gypsum curtain Drainage ditch mg kg mg kg -1 5 mg kg -1 5 mg L mg L -1 2 mg L mg L mg L mg L

17 Ray Bryant s gypsum curtains Width 30cm Depth 1.5m berm

18 ChesapeakeStat.net, verified April 1,

19 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)

20 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

21 The Mattern watershed Well-drained Berks soil no fragipan Somewhat poorly drained Albrights soil fragipan

22 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

23 Runoff monitoring ( ) Hillslope soil No fragipan, well drained Soil P saturation soil indicator only Mehlich-3 P mg/kg Psat = 17% Mehlich-3 P mg/kg Psat = 21% Mehlich-3 P - 78 mg/kg Psat = 9% Riparian soil Fragipan, poorly drained

24 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

25 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

26 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

27 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)

28 Extent of fragipan soil horizons in Mahantango Creek Percent of SSURGO soil map unit mapped as fragipan Data courtesy of Sharon Waltman, USDA NRCS

29 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

30 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

31 Validation efforts are ongoing Ground penetrating radar (GPR) Example transect showing GPR reflectance Base of the plow layer Restrictive layer Courtesy Drohan, Penn State

32 Improved critical source area mapping Restrictive Prone to runoff layer

33 Thanks