Soils data can be specified either in the site parameters, or in a spatial netCDF file containing soils data. The soil values in the site parameters can be replaced at run-time by specifying a soils spatial netCDF file on the command line ("-soil").
| Parameter | Description | Units | Valid Values | Default Values |
|---|---|---|---|---|
| AFIEL(1) through AFIEL(10) | The field capacity of soil layers 1 through NLAYER. Used only if SWFLAG = 0. | cm H2O per cm soil | 0.0 to 1.0 | |
| AWILT(1) through AWILT(10) | The wilting point of soil layers 1 through NLAYER. Used only if SWFLAG = 0, 5, or 6. | cm H2O per cm soil | 0.0 to 1.0 | |
| BASEF | The fraction of the soil water content of deep storage nutrients which is lost via base flow per month (for Century5) or day (for DayCent5). This is used to calculate mineral N, P, and S leaching. | 0.0 to 1.0 | ||
| BULKD(1) through BULKD(10) | Bulk density of soil layers 1 through NLAYER. Used to compute soil loss by erosion, wilting point, and field capacity. Century4 parameter sets have only the parameter BULKD. | g cm -3 or kg liter -1 | 0.0 to 2.0 | |
| CLAY(1) through CLAY(10) | Mass fraction of clay in soil layers 1 through NLAYER. Century4 parameter sets have only the parameter CLAY. | 0.0 to 1.0 | ||
| DRAIN | The fraction of excess water lost by drainage; indicates whether a soil is sensitive for anaerobiosis. | 0.0 to 1.0 | ||
| IVAUTO |
Use
Burke's equations
to initialize soil C pools 0 = the user has supplied the initial values 1 = initialize using the grassland soil parameters 2 = initialize using the crop soil parameters |
0, 1, or 2 | ||
| NELEM |
Number of elements (besides
C
) to be simulated: 1 = simulate N 2 = simulate N and P 3 = simulate N, P and S |
1, 2, or 3 | 1 | |
| NLAYER | The number of initial soil layers. The number will vary during a simulation with erosion, deposition, and homogenization of the simulation depth. With erosion, LAYER can decrease to 1 layer. Cultivation may homogenize layers, decreasing NLAYER. Soil water stored in these layers is specified in AVH2O(2), and is used for root uptake of water and nutrients. In contrast, parameter NLAYPG determines water stress, and NLAYPG ≤ number of soil layers. If a 10th layer is specified, this is used to initialize the deep store for leached mineral N, P, and S. | 1 to 10 | ||
| NLAYPG | The number of soil layers in which crop and grass roots uptake water, and represent the number of soil layers that control water stress in plants. Soil water stored in these layers is specified in AVH2O(1), and is used for potential production, growth, and root death. The number will vary during a simulation with erosion, deposition, and homogenization of the simulation depth. For trees, the entire soil profile is used for root water uptake. | 1 to NLAYER | ||
| PH | Soil pH used to calculate the solubility of secondary P within the boundaries specified by PHESP(1) and PHESP(3). | 0.0 to 14.0 | ||
| PSLSRB | Slope term which controls the fraction of mineral P that is labile. This is used with the parameter SORPMX to calculate the labile fraction of P. This value should reflect the rooting depth (NLAYPG). | |||
| RUNOFF(1), RUNOFF(2), RUNOFF(3) |
Coefficients to the runoff equation: runoff = Aw2 + Bw - C
where w is the surface water, A is RUNOFF(1), B is
RUNOFF(2), and C is RUNOFF(3). If all three parameters are zero, the default
values are used.
|
0.0, 0.55, 2.75 | ||
| SAND(1) through SAND(10) | Mass fraction of sand in soil layers 1 through NLAYER. Century4 parameter sets have only the parameter SAND. | 0.0 to 1.0 | ||
| SILT(1) through SILT(10) | Mass fraction of silt in soil layers 1 through NLAYER. Century4 parameter sets have only the parameter SILT. | 0.0 to 1.0 | ||
| SITLAT | Latitude of the simulation site. This is used in the PET calculation. | degrees | -90.0 to 90.0 | none |
| SITLNG | Longitude of model site. This is for reference only. | degrees | -180.0 to 180.0 | none |
| SORPMX | Maximum P sorption potential for a soil. This is used with the parameter PSLSRB to calculate the labile fraction of P. This value should reflect the rooting depth (NLAYPG). | |||
| STORMF | The fraction of flow from NLAYER to NLAYER +1 which goes into storm flow. | 0.0 to 1.0 | ||
| SWFLAG |
Flag indicating the source of the initial values for the wilting point (AWILT)
and field capacity (AFIEL) arrays: 0 = Use actual data from the site parameter set for both AWILT and AFIEL. 1 = Use Gupta and Larson for both AWILT (-15 bar) and AFIEL (-0.33 bar) [old way, Century version 3]. 2 = Use Gupta and Larson for both AWILT (-15 bar) and AFIEL (-0.10 bar). 3 = Use Rawls for both AWILT (-15 bar) and AFIEL (-0.33 bar). 4 = Use Rawls for both AWILT (-15 bar) and AFIEL (-0.10 bar). 5 = Use Rawls for AFIEL (-0.33 bar) with actual data for AWILT. 6 = Use Rawls for AFIEL (-0.10 bar) with actual data for AWILT. |
0, 1, 2, 3, 4, 5, or 6 | ||
| THICK(1) through THICK(10) | Thickness of soil layers 1 through NLAYER. DayCent4 parameter sets do not have this parameter (they use the parameters ADEP(*) from the fixed parameter set.) | cm |