Trends in Nutrient Sources in The Chesapeake Bay

Watershed

Factors Considered

Point Sources Non-Point Sources

Agricultural manure and fertilizer Non-Ag Fertilizer (residential/commercial) Septic Systems

Septic and manure are reported at 10 and 5 year intervals.

Point sources and fertilizer are 1 year interval.

Areas of Focus

Monitoring Stations at Fall Line Potomac, Susquehanna, Patuxent,

and James Rivers Looked at total Nitrogen, total

Phosphorus

Methods (brief)

Ag fertilizer – calculated a Bay-wide application rate

Non-ag Fertilizer – applied fertilizer within the county of sale.

Manure - applied fertilizer within the county of generation.

Septic – Based on county population, distributed by low density residential.

Point Sources – within designated receiving water

James River – NPS Nitrogen

0

5000

10000

15000

20000

25000

30000

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Total

Ag

Urban

James River – Direct Nitrogen

0

200

400

600

800

1000

1200

1400

1600

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Point Source

Septic

James River – NPS Phosphorus

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Total

Ag

Urban

James River – Direct Phosphorus

Point Source

0

50

100

150

200

250

300

350

400

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Point Source

Patuxent River – NPS Nitrogen

0

500

1000

1500

2000

2500

3000

3500

1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

Total

Ag

Urban

Patuxent River – Direct Nitrogen

0

50

100

150

200

250

300

350

400

450

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Point Source

Septic

Patuxent River – NPS Phosphorus

0

100

200

300

400

500

600

700

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Total

Ag

Urban

Patuxent River – Direct Phosphorus

Point Source

0

5

10

15

20

25

30

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Point Source

Potomac River – NPS Nitrogen

0

20000

40000

60000

80000

100000

120000

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Total

Ag

Urban

Potomac River – Direct Nitrogen

0

500

1000

1500

2000

2500

3000

3500

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Point Source

Septic

Potomac River – NPS Phosphorus

0

5000

10000

15000

20000

25000

30000

35000

40000

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Total

Ag

Urban

Potomac River – Direct Phosphorus

Point Source

0

100

200

300

400

500

600

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Point Source

Susquehanna at Conowingo – NPS Nitrogen

0

20000

40000

60000

80000

100000

120000

140000

160000

180000

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Total

Ag

Urban

Susquehanna at Conowingo – Direct Nitrogen

0

2000

4000

6000

8000

10000

12000

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Point Source

Septic

Susquehanna at Conowingo – NPS Phosphorus

0.00E+00

1.00E+04

2.00E+04

3.00E+04

4.00E+04

5.00E+04

6.00E+04

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Total

Ag

Urban

Susquehanna at Conowingo – Direct Phosphorus

Point Source

0

200

400

600

800

1000

1200

1400

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

Point Source

Future Trend Factors

Nutrient management/Soil testing Phytase in Poultry Precision feeding of cattle Enhanced nutrient management,

nutrient trading

Fertilizer Sales Versus Crop Need

YearNitrogen R (observed)

Phosphorus R (observed)

1994 1.41 1.30

1996 1.36 1.22

1997 1.33 1.22

1998 1.33 1.14

1999 1.37 1.10

2000 1.49 1.16

2001 1.25 0.99

2002 1.36 1.04

Mean 1.36 1.15

Slope (p-value) -0.5% (0.612) -3.6% (0.001)

Phytase Reduction in Poultry Litter

SourceManure

Source

Pre-phytase (lbs P2O5 /

dry)

Post-phytase (lbs P2O5 /

dry ton)# samples

% change

Delaware Broiler 79.5 61.7 484 -23.0 %

Virginia /Maryland

Broiler and Turkey mixed

89.4 72.5 1,665 -18.9 % α

Pennsylvania * * * * -17.0 % β

WestVirginia

Broilers 80.4 71.5 194 -11.1 % γ

NRCS/MWPS Broilers 77.2 64.4 n/a -16.6 %

α – No breakdown of percentages between species, turkey normally has higher P excretions/unit waste.β - Pennsylvania submitted results of assessment given by a feed industry representative, est. 90% adoption.γ - Post-phytase data for West Virginia data was for the period 2001 to 2004, assume phytase adoption overlap.

Summary

In Bay watershed as a whole: Nitrogen total has increased slightly from early 1990s to present day, Phosphorus total has decreased slightly from an early 1990 peak.

In tributaries: mixed bag, some increases, some decreases.

Point Source phosphorus seems to be trending up. Density of Nitrogen on a per acre basis has

increased slightly for ag. Land. Phosphorus decrease on a per acre basis on ag.

land. Density of application of N and P on urban land

has increased substantially (20-50%).