Phase 5 Nutrient Land Calibration

Jing Wu

01/25/2006

Modeling Subcommittee

Nutrient land calibration

Edge of Field

• Calibrated Edge of Field (EOF) loading to targets for each land use– Identify sensitive parameters– Develop decision rules– Develop automatic calibration method

Land Uses Simulated9 non-Ag land uses

• Forest• Harvested Forest

• Low Intensity Pervious Urban• High Intensity Pervious Urban• Low Intensity Impervious Urban• High Intensity Impervious Urban• Bare-construction

• Extractive• Natural Grass

16 Ag land uses

• High Till with manure• Nut Man High Till with manure• Low Till with Manure• Nut Man Low Till with manure• High Till without manure• Nut Man High Till without manure• Hay with nutrients• Nut Man Hay with nutrients• Hay without nutrients• Alfalfa• Nut Man Alfalfa• Pasture• Nut Man Pasture• Trampled• Animal Feeding Operations• Nursery

Nutrient targets for each land use

• Targets for NO3, NH3, and Organic N estimated based on Phase 4 model results and literature values

• One single value for each non-agricultural land use/each pollutant

• Spatial varied targets for agricultural land uses

Trees

Roots Leaves

ParticulateRefractoryOrganic N

ParticulateLabile

Organic N

SolutionAmmonia

Nitrate

Solution

LabileOrganic N

Adsorbed

Ammonia

SolutionRefractoryOrganic N

Nitrogen Cycle in Watershed Model A

tmos

pher

ic

Dep

osit

ion

Den

itri

fica

tio

n

Export

Export Export ExportExport Export Export

(After HSPF documentation)

Trees

Roots Leaves

ParticulateRefractoryOrganic N

ParticulateLabile

Organic N

SolutionAmmonia

Nitrate

Solution

LabileOrganic N

Adsorbed

Ammonia

SolutionRefractoryOrganic N

Nitrogen Cycle in Watershed Model A

tmos

pher

ic

Dep

osit

ion

Den

itri

fica

tio

n

Export

Export Export ExportExport Export Export

(After HSPF documentation)

KAM

KNI

KDNI

KIMAM

KLON KRONKVOL

Trees

Roots Leaves

ParticulateRefractoryOrganic N

ParticulateLabile

Organic N

SolutionAmmonia

Nitrate

Solution

LabileOrganic N

Adsorbed

Ammonia

SolutionRefractoryOrganic N

Nitrogen Cycle in Watershed Model D

enit

rifi

cati

on

(After HSPF documentation)

KAM

KNI

KDNI

KIMAM

KLON KRONKVOL

DIN / ORGN splitTN

DIN / ORGN splitTN

LORGNTN

RORGNTN

NH3 / NO3 split

NO3TN

NH3TN

Calibration strategies

Two parallel strategies tried:

I. Calibrated to three targets: NH3, NO3 and ORGN

II. Targets break into surface and below surface, and Organic N separated to labile and refractory

Total eight targets: SNH3, BNH3, SNO3, BNO3, SLON, BLON, SRON, BRON

Calibration Strategy – 3 Targets

SURFACE

INTERFLOW

Groundwater}NH3NO3ORGN

Calibration Strategy – 8 Targets

SURFACE

INTERFLOW

Groundwater

}NH3NO3Labile ORGNRefractory ORGN

NH3NO3Labile ORGNRefractory ORGN

• Decision rules developed to relate sensitive parameters to three targets

KAM ~ Inorganic N targets /simulated

KIMAM ~ simulated Inorganic N/ targets

KNI ~ (simulated NH3/NO3)/(NH3 targets/NO3)

KDNI ~ simulated NO3/NO3 targets

KLON/KRON ~ Org N targets /simulated

If Organic N OK, but low NO3 and high NH3 -

KVOL ~ simulated NH3/NH3 targets

Strategy I – three targets

• Program written to automatically calibrate all land uses/all segments

• Sample results show how the methodology works

land use: harvest forest

targets: NH3 = 0.208

NO3 = 14

ORGN= 5.79

0.0

0.1

0.2

0.3

0.4

0 50 100 150 200 250 300

NH

3 (

Lb

s/a

cre

/year)

1st round

3rd round

10th round

5

10

15

20

25

30

0 50 100 150 200 250 300

NO

3 (

Lb

s/a

cre

/year)

1st round

3rd round

10th round

0

5

10

15

20

25

30

0 50 100 150 200 250 300

OR

GN

(lb

s/a

cre

/year) 1st round

3rd round

10th round

Land calibration results – NH3

Land use

% o

f la

nd s

egm

ents

rea

ched

tar

gets

0

10

20

30

40

50

60

70

80

90

100

for

hvf

puh p

ul b

ar ext

grs

pas

npa tr

p u

rs alf

nal

hyo

hyw n

hy h

om h

wm lw

m nhi

nho

nlo

Land calibration results – NO3%

of

land

seg

men

ts r

each

ed t

arge

ts

Land use

0

10

20

30

40

50

60

70

80

90

100

for

hvf

puh p

ul b

ar ext

grs

pas

npa tr

p u

rs alf

nal

hyo

hyw n

hy h

om h

wm lw

m nhi

nho

nlo

Land calibration results – Org N%

of

land

seg

men

ts r

each

ed t

arge

ts

Land use

0

10

20

30

40

50

60

70

80

90

100

for

hvf

puh p

ul b

ar ext

grs

pas

npa tr

p u

rs alf

nal

hyo

hyw n

hy h

om h

wm lw

m nhi

nho

nlo

Observations from Strategy I

• Overall, the methodology works for about half of land segments

• Different land uses experiencing different problems

• Better decision rules or changes in targets, application data, etc, needed to improve land calibration

Possible solutions for Strategy IDifferent land uses need different solutions:• Forest - over-simulated ORGN,under-simulated NH3, mixed

results for NO3. - decrease ORGN storage, check InorgN/orgn balance

• Urban - reached ORGN targets, but under-simulated NH3 and NO3.

- change targets or application data for NH3 and NO3• Crop - mixed results.

• Hay - mixed results.

• Pasture - mixed results.

- change decision rules, targets, application data, or uptake rate

• Same sensitivity results, only

- Parameters in the first two layers affected surface loading

- Parameters in the 3rd and 4th layer affected below surface loading

• Decision rules developed to relate each target to relevant parameters

Two set of decision rules developed

Strategy II – eight targets

1. ‘No-if’ rules

• Adjust KAM and KIMAM to reach balance between Org N and Inorganic N

• Adjust KNI and KDNI (below surface ONLY) to reach NH4 and NO3

• Adjust KLON and KRON to reach Org N

Some preliminary observations: • The Rules tested for all land uses/all

segments

• Only run five rounds, not enough to reach a conclusion

• Preliminary results show the rules work better for below surface than surface

• The target break-up needs further look

2. ‘ with-if’ rules

• For surface, use the rule 1

• For below surface - 1) Adjust KLON, KRON, KAM, and KIMAM to

reach Organic N

2) If Organic N targets reached, then adjust KNI and KDNI to reach NH4 and NO3

The Rules tested for forest, high tillageResults for forest

0

20

40

60

80

100

BNH4 BNO3 BLON BRON SNH4 SNO3 SLON SRON

Results for hwm

0

20

40

60

80

100

BNH4 BNO3 BLON BRON SNH4 SNO3 SLON SRON

Preliminary observations: • The rules work better for below surface

than surface, better for forest than high tillage

• Balance between NH3 and NO3 hard to reach, particularly for surface layers

• Need to test on other land uses

Overall thoughts…

• Refine calibration rules to improve land calibration

• Possible changes in targets, application data and initial storage

• Different rules may be necessary for different land uses