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Overview

Overview. Introduction into the CANDY model. Results of calibration and simulation procedures:. Trace gas measurement field and black fallow of short term experiment. Plant development of crop rotation (short term experiment) and 100 years NPK plot (13).

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Overview

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  1. Overview • Introduction into the CANDY model. • Results of calibration and simulation procedures: • Trace gas measurement field and black fallow of short term experiment. • Plant development of crop rotation (short term experiment) and 100 years NPK plot (13). • Corg and Nmin of crop rotation (short term experiment) and 100 years plots (1, 6, 13, 18).

  2. environment OM-pools properties management climate data soil properties crop properties management min./org. fertilzers pesticides crop development OM-turnover N-dynamics dynamics of pesticides CANDY model Parameters Driving force soil water dynamics soil temp. dynamics Initialisation initial values observation Output Output fluxes concentrations

  3. CANDY - input data (1) Initial conditions Management data • Preferable initial observations of: • soil moisture • soil mineral nitrogen • Corg or decomposable carbon (CDEC) • At least: • average values of preceding management (crops & yields, org. matter applicatons) • Level of nitrogen application • Soil moisture level • Mineral N fertilization: • - Date • - Quantity (N-Input kg/ha) • - type of fertiliser • Organic manure: • - Date • - Quantity (C –Input kg/ha) • - type of manure • Cropping: • - (Date of sowing) • - Date of emergence • - Date of harvest • - Yield (t/ha) • - N-Uptake (kg/ha) • Soil tillage (>1 dm): • - Date • - Depth

  4. CANDY - input data (2) Climate data • Daily global radiation (J / cm²) • or duration of sunshine (h) • Daily precipitation (mm) • Daily temperature (° C) Alternatives Generated climate data Monthly aggregated data Adaptation of rainfall intensity

  5. CANDY - input data (3) Soil parameters (each soil horizon): • depth of soil horizon (dm) • mineral density (g/cm3) • bulk density (g/cm3) • permanent wilting point (VOL%) • field capacity (VOL%) • clay content < 2µm (M %) • fine silt content 2-6,3 µm (M %) • saturated conductivity (mm/d) • Not necessary but appreciated: • Soil water measurements (VOL%) • observations of C and N dynamics in soil

  6. CREP-Flux CANDY - C-N-Dynamics Nitrogen turnover: linked to carbon mineralization according to the C/N-ratio of the respective fraction. Long term stabilised carbon

  7. Soil texture: T+fS, Körschens (1980) T, Rühlmann (1999) Initialisation - estimation of long term stabilised carbon pool ('inert pool‘ = CLTS) organic carbon: Long term stabilised carbon Corg, Falloon (1998) Soil structure, organic carbon: CIPS, Kuka

  8. { PWP , bare soil PWP*0.75 , with crop Wmin= CANDY - Soil water dynamics surface runoff infiltration evapotranspiration = f( PET, [W-Wmin],…) capacity concept air availabale water soil pore space non available water percolation = f( ks, [W-Wcap] )  CANDY calculates daily changes of water, temperature, carbon and nitrogen

  9. Trace gas measurement field and bare fallow No calibration: using median soil parameters and the 'Körschens' approach to calculate CLTS.

  10. Trace gas measurement field

  11. Trace gas measurement field and bare fallow No calibration: using median soil parameters and the ‘Körschens’ approach to calculate CLTS. No calibration:total organic Carbon is considered to be decomposable Carbon. Calibration to soil moisture and Corg of bare fallow. Calibration to soil moisture and Corg of bare fallow plus additional Carbon source.

  12. Parameters used for simulation

  13. Trace gas measurement field

  14. Bare fallow Sum of squares Standard param. 0.034 Total Corg = dec. 0.139 Calibrated to b. f. 0.019 Sum of squares Standard param. 1393 Total Corg = dec. 88258 Calibrated to b. f. 1987

  15. Plant development of crop rotation and 100 years NPK plot Calibration to soil Corg and N-uptake of crop rotation. Simulating the 100 years NPK plot. Calibration to 100 years NPK plot.

  16. Partial integration of the SIMWASSER crop modell in CANDY plant development dry matter production N-uptake transpiration LAI h=f(DC) d=f(DC)

  17. Calibration to plant development of crop rotation

  18. Distributions of observed to simulated N-uptake Calibration to crop rotation Adapted TK TK parameter crop r. 100 y. Sugar beet 2.92 2.53 Potato 4.58 4.42 Spring barley 0.57 0.82 Winter wheat 1.77 1.14 Simulating the 100 years NPK plot Calibration to 100 years NPK plot

  19. Crop rotation and 100 years plots Calibration to soil Corg and Nmin of crop rotation. Simulating the 100 years plots 1, 6, 13, 18. Calibration to soil moisture, Corg and Nmin of crop rotation. Simulating the 100 years plots 1, 6, 13, 18.

  20. Calibration to crop rotation Adapted Calib. Calib. Parameters (1) (2) dB 1.53 1.36 dM 2.77 2.73 FC - 29.3 PWP - 17.4 FP 24.5 27.0 CLTS-coefficient (Körschens)0.055 0.055 C/NSOM 10.7 8.5 Sum of Calib. Calib. squares (1) (2) Corg0.042 0.042 Nmin 11799 7028

  21. Simulation of 100 years plots (1) Calibration to C, N Sum of Calib. Calib. squares (1) (2) Plot 1 1.76 1.60 Plot 6 1.05 0.93 Plot 13 0.34 0.21 Plot 18 0.16 0.30 (2) Calibration to W, C, N

  22. Conclusions • Decomposition of soil organic matter is not sufficient to explain the measured CO2 emission. • There must be an additional source for measured CO2. • In order to simulate N-uptake by plants, log term data set are not necessary. • Calibration to a short term dataset is not sufficient to simulate Corg changes resulting from different fertiliser variants for a 100 years period. • For the differentiation of the fertiliser variants further parameters has to be adapted.

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