Figure 1. Interrelationship between the soil organic fractions in the Daisy-P Model showing the flow fractions, fX, to the different pools X. AOM1 and AOM2 corresponds to the slowly and easily
degradable added organic matter, respectively. SOM1 and SOM2 corresponds to the slowly and easily degradable soil organic matter, respectively. SOM3 is inert soil organic matter. The soil microbial biomass is subdivided into SMB1 and SMB2 which is considered to be the stable and the dynamic fraction, respectively... 2-12 Figure 2. Soil temperature factor. ... 2-15 Figure 3. Pressure potential factor... 2-16 Figure 4. Clay content factor... 2-16 Figure 5. Analysis of rescaling of plots using initial and final values. Modified from Nodvin et al. (1986). ... 3-20 Figure 6. DOC sorption isotherms from estimated sorption parameters, m and b, by the pedotransfer
functions listed in Tables 1 and 2 (lines), respectively, together with measured data at pH 5 and pH 7 (dots) for the Ap, EB, and Bt horizons, respectively. ... 3-23 Figure 7. The Initial Mass isotherm... 3-24 Figure 8. Schematic representation of the sorption kinetics coupled to the equilibrium given by the
Langmuir isotherm. ... 4-31 Figure 9. Schematic representation of the agro-ecosystem model Daisy. The model comprises three
main modules, a bio climate, vegetation, and a soil component (Hansen, 2002). ... 7-39 Figure 10. Schematic representation of the ecosystem in the P-Model. ... 7-40 Figure 11. Relational diagram of the P-model receiving its driving variables from Daisy. Rectangles
represent system state variables, while valve symbols represents processes. Solid lines represent flows of matter while broken lines represent flows of information. ... 7-41 Figure 12. Flow chart of the input and output data of Daisy and the P-module... 7-42 Figure 13. Conceptual illustrating the items called by the main program. ... 7-43 Figure 14. View of the spreadsheet Daisy-P.xls point 1-6. ... 8-52 Figure 15. View of the spreadsheet Daisy-P.xls point 7-11. ... 8-53 Figure 16. Comparing basic mineralization calculated by the P-Model and the Daisy model... 9-55 Figure 17. Comparing basic turnover of organic matter calculated by the P-Model and the Daisy model.
... 9-56 Figure 18. The precipitation specified in the weather file, the soil temperature calculated by the heat
module in the Daisy model, and the total soil water content in the profile (0-50 cm) calculated by Daisy (Richards’s equation) and transferred to the P-Model... 9-57 Figure 19. Amount of DON, NH4, and NO3 (left) in the profile (0-50 cm) calculated by the two models,
and amount DOP and DIP (right) in the profile (0-50 cm) calculated by the P-Model, when solutes are transported by convection... 9-57 Figure 20. The turnover of the AOM pools of N and P in the top figures, left and right, respectively. The
dynamic of the inorganic N pools and P pool in the bottom figures, left and right, respectively. ... 9-58 Figure 21. Ryegrass crop uptake of N and P and crop contents of N and P in the top figures, left and
right, respectively. Root exudes and dead roots of N and P to the soil, called plant residuals, and dead plant parts on the surface are shown in the bottom figures, left and right,
respectively. ... 9-59 Figure 22. Test of the DOM sorption module. Applying three different concentration levels of DOC
Figure 23. Test of the calculation of equilibrium equations for the three sorption processes, adsorption, absorption and fixation. Calculations by the P-Model are compared with spreadsheet
calculations of Langmuir estimated immobilized fractions... 9-61 Figure 24. Effect of turnover rate on DOM-C concentrations in the profile. Simulation using two turnover rates for DOM. Horizon 1 = 0-30 cm. Horizon 2 = 30-50 cm. Horizon 3 = 50-70 cm. Horizon 4 = 70-130 cm. Horizon 5 = 130-200 cm. ... 10-64 Figure 25. Effect of pH and time of reaction on DOC isotherms for the Ap and Bt horizons. Left: pH 7,
right: pH 5. Each data point represents the average of two replicates... 10-68 Figure 26. Effect of pH and time of reaction on DOP isotherms for the Ap and Bt horizons. Left: pH 7,
right: pH 5. Each data point represents the average of two replicates... 10-69 Figure 27. Kinetics of DOP sorption/desorption batch experiments using different values for rate
constants when applying 0-0.03 mM DOP to a batch system. Simulations are compared to measured data of sorption experiments, Ap horizon pH 7. ... 10-70 Figure 28. The effect of DOC sorption kinetics using different values for the rate constants on the DOC
concentrations in the bottom of the horizons. The results shown are the results of simulations by the P-Model with organic matter turnover, DOM sorption, and solute and water transport. No crops are defined. Horizon 1 = 0-30 cm. Horizon 2 = 30-50 cm. Horizon 3 = 50-70 cm. Horizon 4 = 70-130 cm. Horizon 5 = 130-200 cm... 10-71 Figure 29. Calibration of DOC sorption with measured data of batch experiments using reaction rate
constants k1 = k2 = 0.001 per hour. ... 10-72 Figure 30. Calibration of DOP sorption with measured data of batch experiments using reaction rate
constants k1 = k2 = 0.001 per hour. ... 10-73 Figure 31. The effect of DOM sorption/desorption on the organic matter turnover in the profile (0-200
cm) with a simulation of continuously applied manure by grassing cows and clover grass in the field. ... 10-74 Figure 32. P sorption isotherms for the Farre (pH 5) and Burrehøjvej (pH 7) field soils for different time
of reactions, 1 minute and 7 days. Points are measured data and lines are Langmuir fitted isotherms. Triangles = Ap-horizons. Squares = B-horizons. Open points = samples after 1 minute, and filled points = samples after 7 days. Total sorbed P is calculated as the
difference between added P and measured P in samples plus oxalate extractable P, Pox.. 10-
77
Figure 33. Dynamics of inorganic P sorption model using different rate constants. The simulations show a batch experiments applying 0-0.6 mM P to a 1:100 soil:water system. ... 10-79 Figure 34. Dynamic of inorganic P sorption model using different size of affinity constants. The
simulations show a batch experiments applying 0-0.6 mM P to a 1:100 soil:water system. 10- 80
Figure 35. Dynamic of inorganic P sorption model using different distribution of absorbed and fixed fractions. The simulations show a batch experiments applying 0-0.6 mM P to a 1:100
soil:water system. ... 10-81 Figure 36. Phosphate sorption with time for Burrehøjvej Ap horizon. P-Model (line) fitted to experimental
results (dots) by parameters listed in Table 11. Note that the y-axis varies... 10-83 Figure 37. Phosphate sorption with time for Burrehøjvej Bt horizon. P-Model (line) fitted to experimental results (dots) by parameters listed in Table 11. Note that the y-axis varies... 10-83 Figure 38. Phosphate sorption with time for the Farre Ap horizon. Simulation by the P-Model (line) by
parameters listed in Table 11, and experimental results (dots) obtained by (Hansen et al.,1999). Note that the y-axis varies. ... 10-84 Figure 39. Phosphate sorption with time for Farre Ap horizon. Simulation by the P-Model (line) by
parameters listed in Table 12, and experimental results (dots) obtained by (Hansen et al.,1999). Note that the y-axis varies. ... 10-85
Figure 40. Phosphate sorption with time for Farre Btg horizon. Simulation by the P-Model (line) by parameters listed in Table 12, and experimental results (dots) obtained by (Hansen et al.,1999). Note that the y-axis varies. ... 10-85 Figure 41. Simulated N2 fixation by clover in the 9. year grass clover field. ... 11-89
Figure 42. Daily and cumulative precipitation (top) and actual evapotranspiration (bottom) at Burrehøjvej field at Research Center Foulum given by the weather file and calculated by Daisy, respectively... 11-90 Figure 43. Simulated dry matter production of crops from 1994-2003 in the three fields at Burrehøjvej by
the Daisy model. Top figure: 9 years of clover grass with grazing cows. Middle figure: 8 year of clover grass then soil ploughing. Bottom figure: 1 year of clover grass then soil ploughing.
... 11-91 Figure 44. DOC concentration in suction cups (dots) (Vinther et al., 2004) and simulated by the Daisy
code (lines) in the Burrehøjvej field soil profiles at 30, 60, and 90 cm depth in three soil treatments: left figures: 9 year grass clover with grazing cows. Middle figures: 8 year grass clover with grazing cows then soil ploughing. Right figures: 1 year grass clover with grazing cows then soil ploughing... 11-92 Figure 45. DON concentration in suction cups (dots) (Vinther et al., 2004) and simulated by the Daisy
code (lines) in the Burrehøjvej field soil profiles at 30, 60, and 90 cm depth in three soil treatments: left figures: 9 year grass clover with grazing cows. Middle figures: 8 year grass clover with grazing cows then soil ploughing. Right figures: 1 year grass clover with grazing cows then soil ploughing... 11-93 Figure 46. NO3 concentration in suction cups (dots) (Vinther et al., 2004) and simulated by the Daisy
code (lines) in the Burrehøjvej field soil profiles at 30, 60, and 90 cm depth in three soil treatments: left figures: 9 year grass clover with grazing cows. Middle figures: 8 year grass clover with grazing cows then soil ploughing. Right figures: 1 year grass clover with grazing cows then soil ploughing... 11-94 Figure 47. NH4 concentration in suction cups (dots) (Vinther et al., 2004) and simulated by the Daisy
code (lines) in the Burrehøjvej field soil profiles at 30, 60, and 90 cm depth in three soil treatments: left figures: 9 year grass clover with grazing cows. Middle figures: 8 year grass clover with grazing cows then soil ploughing. Right figures: 1 year grass clover with grazing cows then soil ploughing... 11-95