Phase 5 Nutrient Land Calibration

1. Phase 5 Nutrient Land Calibration Jing Wu 01/25/2006 Modeling Subcommittee

2. 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

3. 9 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 Land Uses Simulated

4. 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

5. Export Export Export Export Export Export Export Nitrogen Cycle in Watershed Model (After HSPF documentation) Trees Denitrification Roots Leaves Nitrate Atmospheric Deposition Particulate Particulate Solution Labile Refractory Ammonia Organic N Organic N Solution Solution Adsorbed Refractory Labile Ammonia Organic N Organic N

6. Export Export Export Export Export Export Export Nitrogen Cycle in Watershed Model (After HSPF documentation) Trees Denitrification KDNI Roots Leaves Nitrate Atmospheric Deposition KNI Particulate Particulate Solution KIMAM Labile Refractory Ammonia Organic N Organic N KVOL KAM KLON KRON Solution Solution Adsorbed Refractory Labile Ammonia Organic N Organic N

7. Nitrogen Cycle in Watershed Model (After HSPF documentation) Trees Denitrification NO3 TN KDNI Roots Leaves Nitrate NH3 / NO3 split KNI DIN / ORGN split TN Particulate Particulate Solution KIMAM Labile Refractory Ammonia Organic N Organic N KVOL KAM KLON KRON NH3 TN DIN / ORGN split TN LORGN TN RORGN TN Solution Solution Adsorbed Refractory Labile Ammonia Organic N Organic N

8. 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

9. Calibration Strategy – 3 Targets } SURFACE INTERFLOW NH3 NO3 ORGN Groundwater

10. Calibration Strategy – 8 Targets NH3 NO3 Labile ORGN Refractory ORGN } SURFACE INTERFLOW NH3 NO3 Labile ORGN Refractory ORGN Groundwater

11. Strategy I – three targets • 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

12. 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

14. Land calibration results – NH3 % of land segments reached targets Land use

15. Land calibration results – NO3 % of land segments reached targets Land use

16. Land calibration results – Org N % of land segments reached targets Land use

17. 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

18. Possible solutions for Strategy I Different 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

19. Strategy II – eight targets • 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

20. 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

21. 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

22. 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

23. The Rules tested for forest, high tillage

24. 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

25. 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