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Phase 5 Nutrient Land Calibration

Phase 5 Nutrient Land Calibration. Jing Wu 04/04/2006 Modeling Subcommittee. Calibration Targets – 8 for each land use. NH 3 NO 3 Labile ORGN Refractory ORGN. }. SURFACE. INTERFLOW. (“slow” surface flow). lower soil layer. NH 3 NO 3 Labile ORGN Refractory ORGN. Groundwater.

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Phase 5 Nutrient Land Calibration

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  1. Phase 5 Nutrient Land Calibration Jing Wu 04/04/2006 Modeling Subcommittee

  2. Calibration Targets – 8 for each land use NH3 NO3 Labile ORGN Refractory ORGN } SURFACE INTERFLOW (“slow” surface flow) lower soil layer NH3 NO3 Labile ORGN Refractory ORGN Groundwater

  3. Calibration Strategy • Decision rules developed to relate each target to relevant parameters - Parameters in the first two layers affected surface loading - Parameters in the 3rd and 4th layer affected below surface loading

  4. Status at last meeting: • Only two land uses tested • Most EoF targets not reached • Suggested changes on application data, EoF targets, and different decision rules

  5. Changes made since last meeting: • Application data (timing, plant uptake curve, etc..) • EoF targets TN remains same, changes in break-up between different species Surface: NH3/NO3 = 1:10 Subsurface: NH3/NO3 = 1:5 • Calibration strategy – decision rules different for different land uses - forest - crop, hay

  6. Forest Calibration • Targets changed based on literature values and P4.3 results TN = 1.7(lbs/acre/yr), same targets everywhere • Same decision rules as applied before

  7. Crop calibration Three goals need to be accomplished: 1.EoF loads within reasonable range of targets 2. Plant N uptake simulated correctly, within reasonable range of observed data (critical, account for most of N loss) 3. Stable N storage over time

  8. Calibration Strategy • Optimize parameters as did for Forest - to reach EoF targets • Optimize initial storages for labile and refractory organic nitrogen - to eliminate huge spike at the first year due to high initial storage - to stabilize storage over time

  9. Related initial storage to organic N export at the first three years

  10. Calibration Strategy (cont.) • Improve simulation on crop uptake - Change the timing of application data - Return 60% plant N to refractory organic N . act as a way to harvest plant (will increase refractory organic N export, though)

  11. Old data Application timing closer to uptake After fixed storage and plant N return

  12. Percent of each crop 8% 42% 50%

  13. High till with manure

  14. High till without manure

  15. Low till with manure

  16. Comparison of regular crop and nutrient management crop • Test model’s capacity of simulating management actions • Use the calibrated land parameters to run nutrient management land • TN and plant uptake compared

  17. Comparison of hom and nho On average, 32% lower On average, 11% lower

  18. Preliminary observations: • New results promising • Majority of EoF loadings within reasonable range of targets • Plant N uptake within the range of observed data • Further refinement needed

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