Nutrient Management and Edge of Field Monitoring Conference December 1-3, 2015 Memphis, TN

1. Linking Agricultural Practices
to Water Quality Improvement
William Crumpton & Matt Helmers
Iowa State University

2.  Performance of in-field practices
 NPS N & P loads delivered to streams
 Wetlands intercepting NPS loads
 Watershed scale outcomes
Linking Agricultural Practices to
Water Quality Improvement:

3. [N]
N Response Curves
N Application Rate
( function of practices)
Practices by field
Water Yield by field
(also yield, for economic analyses)
Established based on
experimental field studies
Established based on GIS
coverages and survey data
Estimated based on
observed flows,
precipitation, etc. and
semi-empirical models
N yield by field
[N] by field
Predicted load at
watershed outlet
Observed load at
watershed outlet
Estimated as
 𝑵 𝒚𝒊𝒆𝒍𝒅 𝒂𝒄𝒓𝒐𝒔𝒔 𝒇𝒊𝒆𝒍𝒅𝒔
Calculated based on close
interval monitoring of
flows and concentrations
Comparison of predicted and observed load for
1) Validation and error estimation
2) Iterative improvement of approach/tool
3) Establishing capabilities and limitations of approach/tool
(IDALS and INRC)
(Iowa Corn Promotion Board
and USDA)
(IDALS and USDA NIFA)
(IDALS and INRC)
(IDALS, INRC, and USDA-NRCS)
Conceptual Framework

4. Plot Scale Research Facilities

5. Delivery Scale Monitoring Sites
Plot Scale Research Facilities

6.  Performance of in-field practices
 NPS N & P loads delivered to streams
 Wetlands intercepting NPS loads
 Watershed scale outcomes
Linking Agricultural Practices to
Water Quality Improvement:

7. Field scale reflects processes and practices but
may not reflect actual delivery to streams

8. Field scale reflects processes and practices but
may not reflect actual delivery to streams
Field to stream
transport

9. Larger scales reflect combination of
delivery and in-stream processes
Field scale reflects processes and practices but
may not reflect actual delivery to streams
Field to stream
transport

10. Larger scales reflect combination of
delivery and in-stream processes
Field scale reflects processes and practices but
may not reflect actual delivery to streams
Field to stream
transport
In-stream
processes

11. Larger scales reflect combination of
delivery and in-stream processes
This scale reflects nutrient load
actually delivered to stream
Field scale reflects processes and practices but
may not reflect actual delivery to streams
Field to stream
transport
In-stream
processes

13. Monitoring sites instrumented
for close interval sampling and
flow measurement

14.  Performance of in-field practices
 NPS N & P loads delivered to streams
 Wetlands intercepting NPS loads
 Watershed scale outcomes
Linking Agricultural Practices to
Water Quality Improvement:

15. Nitrate and Total Phosphorus: Yields and flow-weighted average concentrations
versus rank order
Minimums: FWA NO3=3.32, NO3 yld=2.3, FWA TP=39, TP yld=0.043.
0
5
10
15
20
25
30FWANitrateConcentration
(mgNL-1)

16. Nitrate and Total Phosphorus: Yields and flow-weighted average concentrations
versus rank order
Minimums: FWA NO3=3.32, NO3 yld=2.3, FWA TP=39, TP yld=0.043.
0
5
10
15
20
25
30FWANitrateConcentration
(mgNL-1)
0
50
100
150
200
250
300
350
400
450
500
FWATotalPhosphorus
Concentration(ppb)

17. Nitrate and Total Phosphorus: Yields and flow-weighted average concentrations
versus rank order
Minimums: FWA NO3=3.32, NO3 yld=2.3, FWA TP=39, TP yld=0.043.
0
5
10
15
20
25
30FWANitrateConcentration
(mgNL-1)
0
10
20
30
40
50
60
70
80
90
100
NitrateYield
(kgNha-1yr-1)
0
50
100
150
200
250
300
350
400
450
500
FWATotalPhosphorus
Concentration(ppb)

18. 0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
TotalPhosphorusYield
(kgha-1yr-1)
Nitrate and Total Phosphorus: Yields and flow-weighted average concentrations
versus rank order
Minimums: FWA NO3=3.32, NO3 yld=2.3, FWA TP=39, TP yld=0.043.
0
5
10
15
20
25
30FWANitrateConcentration
(mgNL-1)
0
10
20
30
40
50
60
70
80
90
100
NitrateYield
(kgNha-1yr-1)
0
50
100
150
200
250
300
350
400
450
500
FWATotalPhosphorus
Concentration(ppb)

19. Site
Average TN
Yield
(kg/ha/yr)
Average
Nitrate Yield
(kg N/ha)
Nitrate
percent of
TN
CLA1 27 26 98
PAL16 29 28 97
PAL11 37 36 96
POC2 37 37 98
PAL3 37 35 92
POC8 45 43 97
PAL5 48 46 94
PAL7 50 48 97
Average yields: Total nitrogen and nitrate
0
10
20
30
40
50
60
CLA1 PAL16PAL11 POC2 PAL3 POC8 PAL5 PAL7
Concentration(mgN/L)
Average TN Yield
(kg/ha/yr)
Average Nitrate Yield
(kg N/ha)
y = 0.96x
R² = 0.99
0
10
20
30
40
50
60
0 20 40 60
Nitrateyield(kgN/ha)
Total nitrogen yield (kg N/ha)

20. Average TP
Yield
(kg/ha/yr)
Average TRP
Yield
(kg/ha/yr)
TRP
percent of
TP
CLA1 0.46 0.36 78
PAL3 0.76 0.55 72
PAL5 0.73 0.49 67
PAL7 1.04 0.82 79
PAL11 0.88 0.75 85
PAL16 0.41 0.33 80
POC2 0.33 0.24 73
POC8 0.52 0.39 75
Average yields: Total phosphorus and total reactive phosphorus

21.  Wide range in N & P yields across systems having similar
land use, soils and drainage.
– How much of this variation can be attributed to in field management?
 Very large annual variation in N & P loads
– What are implications for load reduction targets?
 Tile drains deliver much higher P loads to streams than
previously thought based on plot scale research.
 Surface runoff contributes only about half of the total P load
in these tile drained landscapes.
– Practices that target surface runoff will have less effect on P loads than
expected.
NPS N & P loads delivered to streams

22.  Wide range in N & P yields across systems having similar
land use, soils and drainage.
– How much of this variation can be attributed to in field management?
 Very large annual variation in N & P loads
– What are implications for load reduction targets?
 Tile drains deliver much higher P loads to streams than
previously thought based on plot scale research.
 Surface runoff contributes only about half of the total P load
in these tile drained landscapes.
– Practices that target surface runoff will have less effect on P loads than
expected.
NPS N & P loads delivered to streams

23.  Wide range in N & P yields across systems having similar
land use, soils and drainage.
– How much of this variation can be attributed to in field management?
 Very large annual variation in N & P loads
– What are implications for load reduction targets?
 Tile drains deliver much higher P loads to streams than
previously thought based on plot scale research.
 Surface runoff contributes only about half of the total P load
in these tile drained landscapes.
– Practices that target surface runoff will have less effect on P loads than
expected.
NPS N & P loads delivered to streams

24.  Wide range in N & P yields across systems having similar
land use, soils and drainage.
– How much of this variation can be attributed to in field management?
 Very large annual variation in N & P loads
– What are implications for load reduction targets?
 Tile drains deliver much higher P loads to streams than
previously thought based on plot scale research.
 Surface runoff contributes only about half of the total P load
in these tile drained landscapes.
– Practices that target surface runoff will have less effect on P loads than
expected.
NPS N & P loads delivered to streams

25.  Wide range in N & P yields across systems having similar
land use, soils and drainage.
– How much of this variation can be attributed to in field management?
 Very large annual variation in N & P loads
– What are implications for load reduction targets?
 Tile drains deliver much higher P loads to streams than
previously thought based on plot scale research.
 Surface runoff contributes only about half of the total P load
in these tile drained landscapes.
– Practices that target surface runoff will have less effect on P loads than
expected.
NPS N & P loads delivered to streams

26.  Performance of in-field practices
 NPS N & P loads delivered to streams
 Wetlands intercepting NPS loads
 Watershed scale outcomes
Linking Agricultural Practices to
Water Quality Improvement:

27. Corn
Soybean
1 km
Targeted Wetland Restoration
DD Tile
W.G. Crumpton, Iowa State University
There is considerable interest in using wetlands to intercept and
reduce nitrogen loads in tile drained landscapes.

28. Organic N
Soil bound NH4
+
NH4
+
N transformation in wetlands
W.G. Crumpton, Iowa State University

29. NO3
-
Organic N
Soil bound NH4
+
NH4
+
N transformation in wetlands
W.G. Crumpton, Iowa State University

30. NO3
-
Organic N
Soil bound NH4
+
NH4
+
N2
N transformation in wetlands
W.G. Crumpton, Iowa State University

31. NO3
-
External NO3
- Loading
Organic N
Soil bound NH4
+
NH4
+
Fate of NPS nitrate loads in wetlands
W.G. Crumpton, Iowa State University

32. NO3
-
External NO3
- Loading
DenitrificationOrganic N
Soil bound NH4
+
NH4
+
N2
Fate of NPS nitrate loads in wetlands
W.G. Crumpton, Iowa State University

33. W.G. Crumpton, Iowa State University
Wetlands were chosen to ensure a
broad range in factors expected to
affect N loss rates, including:
Nitrate concentration
Hydraulic loading rate
Nitrate loading rate
Sites for Wetland Performance Monitoring

34. W.G. Crumpton, Iowa State University
Wetlands were chosen to ensure a
broad range in factors expected to
affect N loss rates, including:
0
5
10
15
20
FWAnitrate-Nconc.(mg/L)
Rank order: Low to high Nitrate concentration
Hydraulic loading rate
Nitrate loading rate

35. W.G. Crumpton, Iowa State University
Wetlands were chosen to ensure a
broad range in factors expected to
affect N loss rates, including:
0
5
10
15
20
FWAnitrate-Nconc.(mg/L)
Rank order: Low to high
0
0.1
0.2
0.3
0.4
Hydraulicloadingrate
(averagem/day)
Rank order: Low to high
Nitrate concentration
Hydraulic loading rate
Nitrate loading rate

36. W.G. Crumpton, Iowa State University
Wetlands were chosen to ensure a
broad range in factors expected to
affect N loss rates, including:
0
5
10
15
20
FWAnitrate-Nconc.(mg/L)
Rank order: Low to high
0
0.1
0.2
0.3
0.4
Hydraulicloadingrate
(averagem/day)
Rank order: Low to high
0
2000
4000
6000
8000
10000
Nitrate-Nload(kg/ha)
Rank order: Low to high
Nitrate concentration
Hydraulic loading rate
Nitrate loading rate

37. W.G. Crumpton, Iowa State University
Field sites instrumented for
automated sampling and flow
measurement
Monitoring of Wetland Performance

38. 0
5
10
15
20
25
Nitrate-N(mgL-1
)
0
10000
20000
30000
Inflow(m3d-1)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AL Wetland
2007
0
100000
200000
300000
400000
500000
Inflow(m3d-1)
0
5
10
15
20
25
Nitrate-N(mgL-1
)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
BG Wetland
2007
0
5
10
15
20
25
Nitrate-N(mgL-1
)
0
20000
40000
60000
80000
100000
Inflow(m3d-1)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
DJ Wetland
2007
0
5
10
15
20
25
Nitrate-N(mgL-1
)
0
40000
80000
120000
160000
Inflow(m3
d-1
)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
ND Wetland
2007
0
5
10
15
20
25
Nitrate-N(mgL-1
)
0
40000
80000
120000
160000
200000
Inflow(m3
d-1
)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
JR Wetland
2007
0
5
10
15
20
25
Nitrate-N(mgL-1
)
0
40000
80000
120000
160000
200000
Inflow(m3d-1)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
VH Wetland
2007
0
5
10
15
20
25
Nitrate-N(mgL-1
)
0
40000
80000
120000
Inflow(m3d-1)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
HS North Wetland
2007
0
40000
80000
120000
160000
200000
Inflow(m3d-1)
0
5
10
15
20
25
Nitrate-N(mg/L)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
HM Wetland
2006
0
20000
40000
60000
80000
100000
Inflow(m3d-1)
0
5
10
15
20
25
Nitrate-N(mgL-1)
UML Wetland
2004
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
0
20000
40000
60000
80000
100000
Inflow(m3d-1)
0
5
10
15
20
25
Nitrate-N(mgL-1)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
TI Wetland
2006
0
5
10
15
20
25
Nitrate-N(mgL-1
)
0
40000
80000
120000
160000
200000
Inflow(m3d-1)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
KS Wetland
2008
0
5
10
15
20
25
Nitrate-N(mgL-1
)
0
10000
20000
30000
Inflow(m3d-1)Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
DS Wetland
2008
Examples from 2007 to 2009 monitoring
W.G. Crumpton, Iowa State University

39. 0
5
10
15
20
25
Nitrate-N(mgL-1)
0
5000
10000
15000
20000
25000
Inflow(m3d-1)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
0
5
10
15
20
25
Nitrate-N(mgL-1)
0
10000
20000
30000
40000
50000
Inflow(m3d-1)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
0
5
10
15
20
25
Nitrate-N(mgL-1)
0
5000
10000
15000
20000
25000
Inflow(m3d-1)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
W.G. Crumpton, Iowa State University

40. 0
5
10
15
20
25
Nitrate-N(mgL-1)
0
5000
10000
15000
20000
25000
Inflow(m3d-1)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
0
5
10
15
20
25
Nitrate-N(mgL-1)
0
10000
20000
30000
40000
50000
Inflow(m3d-1)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
0
5
10
15
20
25
Nitrate-N(mgL-1)
0
5000
10000
15000
20000
25000
Inflow(m3d-1)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Residence
time
Longer
Shorter
W.G. Crumpton, Iowa State University

41. 0
5
10
15
20
25
Nitrate-N(mgL-1)
0
5000
10000
15000
20000
25000
Inflow(m3d-1)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
0
5
10
15
20
25
Nitrate-N(mgL-1)
0
10000
20000
30000
40000
50000
Inflow(m3d-1)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
0
5
10
15
20
25
Nitrate-N(mgL-1)
0
5000
10000
15000
20000
25000
Inflow(m3d-1)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Residence
time
Longer
Shorter
Hydraulic
Loading
Rate
Lower
Greater
W.G. Crumpton, Iowa State University

42. W.G. Crumpton, Iowa State University

43. W.G. Crumpton, Iowa State University

44. W.G. Crumpton, Iowa State University

45. W.G. Crumpton, Iowa State University

46. W.G. Crumpton, Iowa State University

47. W.G. Crumpton, Iowa State University
Mass loss kg ha-1 yr-1

48. W.G. Crumpton, Iowa State University

49.  Performance of in-field practices
 NPS N & P loads delivered to streams
 Wetlands intercepting NPS loads
 Watershed scale outcomes
Linking Agricultural Practices to
Water Quality Improvement:

50.  Wetland Siting and Design for Watershed
Scale Endpoints
 Potential Load Reductions from Wetland
Restoration and N Management in Iowa
Targeting Wetland Restorations to
Reduce NPS N loads
W.G. Crumpton, Iowa State University

51. Wetland Siting and Design for
Watershed Scale Endpoints
W.G. Crumpton, Iowa State University
Tile
Upland Depression
Upland Non-hydric
Upland Swale
Lowland Drainageway
Soils by Landscape Position
Legend

52. Total Load
50 metric tons
Annual Nitrate Budget
W.G. Crumpton, Iowa State University
Tile
Upland Depression
Upland Non-hydric
Upland Swale
Lowland Drainageway
Soils by Landscape Position
Legend

53. Loss in Ditch and Stream
1.6 metric tons
Exported
48.4 metric tons
Annual Nitrate Budget
W.G. Crumpton, Iowa State University
Tile
Upland Depression
Upland Non-hydric
Upland Swale
Lowland Drainageway
Soils by Landscape Position
Legend

54. Upslope
sites
Loss in Ditch and Stream
1.6 metric tons
Exported
48.4 metric tons
Annual Nitrate Budget
W.G. Crumpton, Iowa State University
Tile
Upland Depression
Upland Non-hydric
Upland Swale
Lowland Drainageway
Soils by Landscape Position
Legend

55. Loss in Ditch and Stream
1.6 metric tons
Exported
46.5 metric tons
Loss in Wetlands
1.9 metric tons
Annual Nitrate Budget
W.G. Crumpton, Iowa State University
Upslope
sites
Tile
Upland Depression
Upland Non-hydric
Upland Swale
Lowland Drainageway
Soils by Landscape Position
Legend

56. Downslope
sites
Loss in Ditch and Stream
1.6 metric tons
Exported
46.5 metric tons
Loss in Wetlands
1.9 metric tons
Annual Nitrate Budget
W.G. Crumpton, Iowa State University
Upslope
sites
Tile
Upland Depression
Upland Non-hydric
Upland Swale
Lowland Drainageway
Soils by Landscape Position
Legend

57. Loss in Ditch and Stream
1.6 metric tons
Loss in Wetlands
17 metric tons
Exported
29.8 metric tons
Loss in Ditch and Stream
1.6 metric tons
Exported
46.5 metric tons
Loss in Wetlands
1.9 metric tons
Annual Nitrate Budget
W.G. Crumpton, Iowa State University
Upslope
sites
Tile
Upland Depression
Upland Non-hydric
Upland Swale
Lowland Drainageway
Soils by Landscape Position
Legend
Downslope
sites

58.  Wetland Siting and Design for Watershed
Scale Endpoints
 Potential Load Reductions from Wetland
Restoration and N Management in Iowa
Targeting Wetland Restorations to
Reduce NPS N loads
W.G. Crumpton, Iowa State University

59.  Nitrate concentration and loads
 Potential load reductions from
improved N management
 Potential load reductions from
targeted wetland restoration
Potential Load Reductions from Wetland
Restoration and N Management in Iowa
W.G. Crumpton, Iowa State University

60. W.G. Crumpton, Iowa State University
Nitrate Concentrations and Loads with Existing N Management

61. W.G. Crumpton, Iowa State University
Nitrate Concentrations and Loads with Existing N Management
Nitrate Concentrations and Loads with MRTN Based N Management

62. Water yield grid
Nitrate yield grid
and loss function
Nitrate loss gridgenerate
W.G. Crumpton, Iowa State University
Estimating Potential Nitrate Loss in Wetlands

63. W.G. Crumpton, Iowa State University
Nitrate Loads & Potential Loss in Wetlands with Existing N Management

64. W.G. Crumpton, Iowa State University
Nitrate Loads & Potential Loss in Wetlands with Existing N Management
Nitrate Load & Potential Loss in Wetlands with MRTN Based N Management

65. W.G. Crumpton, Iowa State University
45% mass reduction
Potential N Reduction in Wetlands with Existing N Management

66. W.G. Crumpton, Iowa State University
45% mass reduction
Reduction due to
Fertilizer Management
Potential N Reduction in Wetlands with MRTN based N Management

67. W.G. Crumpton, Iowa State University
45% mass reduction
Reduction due to
Fertilizer Management
Potential N Reduction in Wetlands with MRTN based N Management

68. [N]
N Response Curves
N Application Rate
( function of practices)
Practices by field
Water Yield by field
(also yield, for economic analyses)
Established based on
experimental field studies
Established based on GIS
coverages and survey data
Estimated based on
observed flows,
precipitation, etc. and
semi-empirical models
N yield by field
[N] by field
Predicted load at
watershed outlet
Observed load at
watershed outlet
Estimated as
 𝑵 𝒚𝒊𝒆𝒍𝒅 𝒂𝒄𝒓𝒐𝒔𝒔 𝒇𝒊𝒆𝒍𝒅𝒔
Calculated based on close
interval monitoring of
flows and concentrations
Comparison of predicted and observed load for
1) Validation and error estimation
2) Iterative improvement of approach/tool
3) Establishing capabilities and limitations of approach/tool
(IDALS and INRC)
(Iowa Corn Promotion Board
and USDA)
(IDALS and USDA NIFA)
(IDALS and INRC)
(IDALS, INRC, and USDA-NRCS)
Conceptual Framework

69. Iowa State University Wetlands Research Lab:
W. Crumpton, A. van der Valk, T. Jurik
G. Stenback, J. Stenback, S. Fisher,
D. Green, I. Ellickson, C. Judge, S. McDeid, H. Hoglund,
K. Halpin, A. Albertson, M. Baalman, J. Eeling
Iowa Department of Agriculture and Land Stewardship
Iowa Department of Natural Resources
US Department of Agriculture
US Environmental Protection Agency
W.G. Crumpton, Iowa State University

71. W.G. Crumpton, Iowa State University

72. W.G. Crumpton, Iowa State University

73. W.G. Crumpton, Iowa State University
Observed Nitrate concentrations and flow rates
for Van Horn Wetland in 2004
Van Horn Wetland
Monitoring of Wetland Performance
0
5
10
15
20
25
Nitrate-N(mgL-1
)
0
40000
80000
120000
160000
200000
Inflow(m3d-1)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
VH Wetland
2007

74. W.G. Crumpton, Iowa State University
Flow
Observed inflow nitrate-N concentration
Observed outflow nitrate-N concentration
Mar Apr May Jun Jul Aug Sep Oct
Van Horn 2004
0
5
10
15
20
25
Nitrate-Nconcentrationmgl-1
0
5000
10000
15000
20000
25000
flowm3day-1
Observed Nitrate concentrations and flow rates
for Van Horn Wetland in 2004
Van Horn Wetland
Monitoring of Wetland Performance

75. Wetland Monitoring Sites
Plot Scale Research Facilities