Managing phosphorus in ditch drained soils of the Delmarva Peninsula

Transcription

1 Managing phosphorus in ditch drained soils of the Delmarva Peninsula Peter Kleinman and Ray Bryant, USDA-ARS Arthur Allen, Univ. Maryland Eastern Shore

2 Delmarva Peninsula 5,500 sq-miles P Loss (lbs/ac/yr) 800,000 tons of litter/yr Kleinman et al., Univ. Md. East. Shore Ditch

3 The importance of drainage Improved agricultural drainage is vital to crop production on the Delmarva Peninsula and in other areas where soils are poorly drained

4 The University of Maryland Eastern Shore Princess Anne, MD

5 UMES Research Farm Representative of local conditions Former poultry operation purchased yrs litter application Maryland FIV ~ Extensive ditch drainage Poorly drained soils

6 Soil test P levels are high on the Eastern Shore of Maryland 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 UMES Worcester Somerset Average P FIV = 374

7 Ditch Monitoring Flume Automatic sampler

8 Univ. Maryland Eastern Shore Farm Ditch monitoring stations Since 2005 Since 2001 Wells and piezometers Since 2004

9 Drainage from field ditches Flow (10 3 m 3 ) Average Ditch depth # (ft) 1 3 2

10 Phosphorus losses P Loss (lbs/ac) Flow (10 3 m 3 ) Ditch ID

11 Impact of point sources Flow (10 3 m 3 ) P Loss (lbs/ac) Ditch ID Mehlich-3 P 3,113 mg/kg

12 Even non-point sources can be important when there s enough rain P Loss (kg/ha) mg/kg 449 mg/kg 382 mg/kg 466 mg/kg mg/kg 421 mg/kg 1 2

13 Phosphorus loss subsurface pathways PPPPPPPPP (> 90%) P (< 10%) Kleinman et al., 2007 (J. Soil Water Conserv.)

14 Pleaching and soil macropores - learning from tile drains Photos courtesy M. Shipitalo, USDA-ARS

15 Delmarva P leaching study - soils Loamy sand Sand Evesboro (Quartzipsamment) Sandy Loam Sandy Clay Loam Sand Sassafras (Hapludult) Silt Loam Silty Clay Loam Sand Quindocqua (Hapludult) Sandy Loam Loam Sand Bojac (Hapludult)

16 High and low P soils Soils in no-till corn, no P applied for at least 11 mo Maryland FIV

17 Soil column collection

18 20-in 12-in

19 Leaching protocol 10 wks before and and 8 wks after litter application (2 T/A litter, 47 lbs P/A) 0.8 in simulated rainfall/week (30 yr average) Rainwater spiked to simulate Smith Island ionic composition

20 P loads before litter application (lbs/ac) Total P in leachate (lbs/ac) A B BC C 5/2/10 6/21/10 8/10/10 9/29/10 11/18/10 Bojac High Bojac Low Evesboro High Evesboro Low Quindocqua High Quindocqua Low Sassafrass High Sassafrass Low

21 P loads in leachate before litter application (lbs/ac) Influence of soil P 5 Total P (lbs/ac) A B "High" "Low" 5/2/10 6/21/10 8/10/10 9/29/10 11/18/10 Total P (lbs/ac) Psat > 20% Psat < 20% A B 5/2/10 6/21/10 8/10/10 9/29/10 11/18/10

22 P saturation threshold for P leaching? EPA Federal Lands Requirement = Total P Total P Leachate P (mg/l) 3 2 1? cm sample Soil P saturation cm sample (~N. Carolina approach)

23 Soil P saturation manipulated by tillage/sampling depth Soil P saturation (M3) M3-P = 610 mg/kg M3-P = 388 mg/kg Soil mixing depth (0 - x inches) Quindoqcua and Sassafrass soils with argillic horizons

24 P loads after litter application (lbs/ac) 5 Total P in leachate (lbs/ac) A B Bojac High Bojac Low Evesboro High Evesboro Low Quindocqua High Quindocqua Low Sassafrass High Sassafrass Low 0 8/28/10 9/11/10 9/25/10 10/9/10 10/23/10

25 Total P loads after litter application (lbs/ac) All soils Total P (lbs/ac) A B 8/28/10 9/11/10 9/25/10 10/9/10 10/23/10 5 Bojac Evesboro Quindocqua Sassafrass Shows why the P Index is relevant to the Delmarva Total P (lbs/ac) A Psat > 20% Psat < 20% 0 8/28/10 9/11/10 9/25/10 10/9/10 10/23/10

26 How to keep manure P from leaching? Flow splitter Tillage wings 8,000 gal/ac Splitter ensures even distribution of slurry across furrow, lower vertical pressure Wings mix slurry with soil Mixing breaks macropore connection

27 Quindocqua dairy slurry application first few months after application Total P in leachate (lbs/ac) B B Cut off transfer of manure P AND soil P from surface soil? A B No manure Disked - in Anti-leach sweeps Surface Kleinman and Allen, unpublished

28 Subsoil disturbance prevents transfers of the highest P concentrations from soil surface Mehlich-3 soil P, mg/kg Depth, cm

29 There s hope for manures but do we really want to advocate deep tillage? 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 What can we do with soils that are very high in P?

30 No change in soil test P after one decade of continuous corn : Zero P additions High soil P has water quality consequences 3 Allegheny Plateau Ridge & Valley Piedmont Coastal Plain Mehlich-3 soil P (mg/kg) Lime 2 1 Dissolved P in runoff (mg/l) Princess Anne, MD 0 UMES Research Farm (Kleinman et al., 2010, Canad. J. Soil Sci.)

31 P transport processes in Coastal Plain soils Depth below land surface (cm) Mehlich-3 P P concentration Drainage ditch 300 mg kg mg kg -1 5 mg kg -1 5 mg L -1 2 mg L mg L -1 10% 90 %

32 FGD gypsum curtain 2 nd generation Depth below land surface (cm) Mehlich-3 P P conc. P binding curtain Drainage ditch 300 mg kg mg kg -1 5 mg kg -1 High P Moderate P Low P berm Low P Low P Low P

33 P binding industrial byproducts Acid mine drainage treatment residuals (Fe & Al oxides) Drinking water treatment residuals (alum) Bauxite mining and production waste (red mud) Fly ash Paper mill waste Steel slag waste FGD gypsum synthetic gypsum (calcium)

34 FGD gypsum curtain 2 nd generation Width 30cm Depth 1.5m 8 curtain segments: 20 m berm

35 FGD gypsum curtain Hurricane Irene Mehlich-3 P P conc. Gypsum curtain Drainage ditch Depth below land surface (cm) mg kg mg kg -1 5 mg kg mg L mg L mg L mg L -1 90% efficiency 0.1 mg L mg L -1

36 FGD gypsum curtain scaling up

37 FGD gypsum curtain scaling up 2 trench along ditch edge Switching to a trencher

38 Questions?