It simulates biophysical processes in cropping systems, especially those related to production and ecological outcomes of management practices in the face of climate risks. The strength of the APSIM framework is its ability to integrate models derived from fragmented research efforts. The SURFACEOM module (Probert et al., 2004) simulates the fate of above-ground crop residues that can be removed from the system, incorporated into the soil or decomposed on the soil surface.
Soil evaporation parameters, Soil albedo, Runoff distribution parameters, Maximum surface water storage capacity, or maximum pond height (mm), equal to the height of the rice field trees in rice-based systems. Build new simulation: Click on the top toolbar at the top of the screen (far left) and select a simulation from default list that is closest to the type of simulation we want to build. To add components to a simulation tree, click the Standard button on the toolbar at the bottom of the window. This will show the standard toolbox containing many components and simulation entities that can be dragged into the simulation tree.
Structurally: It contains one of the important modules - Paddock, where all information especially management, crop, soil, water, organic matter on the surface, etc. The weather properties are located under the Met component in the Rice-Fallow simulation tree. The start and end date of the simulation is correspondingly set according to the first and last date of the met file.
It contains three of the four input parameters such as soil and water, management and crop (eg rice) information.
Addition of component -Soil and water module
In the water module, enter all required hydro-physical measured soil properties (eg bulk density, air-dry moisture content, permanent wilting, field capacity, and saturation, hydraulic conductivity, etc.) layer or depth for the entire profile. ii). In groundwater module, enter SWCON values of the corresponding layers (ranging between 0.7 for pure sand and 0.1 for heavy clay). Enter the values if available, but it is mandatory to have soil texture information (sand, silt and .clay).
Initial Water: Can be specified by selecting one of the radio buttons and then entering a percentage of water or mm of water. Initial Nitrogen: Can be added by dragging and dropping from the SWIM Soil component. A single value for the amount of nitrate or ammonia can be entered for the entire profile (in kg/ha) (by clicking on the corresponding "total" cells in the grid) OR individual layers can be entered in the grid.
Under the paddock component in the simulation tree there are another 3-4 modules such as surface organic matter, fertiliser, micrometer and irrigation. Similarly, surface organic matter indicates how much residue/biomass from the previous crop has been retained in the soil. Surface organic matter: The parameters for the initial surface residuals can be found under the surface organic matter component in the simulation tree.
Fertilizer: This component only needs to be present if we are going to do fertilizer applications in our simulation.
Addition of third Component -Simulation management
Fertilization planning: Here, fertilizer was applied in 3 divisions: 50% as basal, 25% by rotation and the remaining 25% at PI stages of rice growth.
Addition of fourth component-Crop parameters
Output File
Singh Page 25 Similarly, according to our needs, we can choose any of the filters, as shown here (below the window) and with are selected. These variables can be removed and recorded up and down in the same way as the components in the simulation. ii) Reporting Frequency The frequency of the output is determined by the Reporting Frequency subcomponent. Whenever these specified events occur in the simulation, a line containing the current values of the variables is written to the output file.
If we want a daily result, we can achieve this by dragging the end_day event to the left pane. You can find the end_day event by selecting the clock component from the drop-down list in the right pane. Similarly, if we want to display the output only at harvest (annual yield), we must write harvest instead of end_day.
Multiple Simulations
Running the simulation(s)
Clicking on the summary file component gives you quick access to the contents of this file. When looking for errors, always scroll down to the first error and fix it first.
Presentation of output in graphical format and exporting to Excel
Now click on simulation, output file with date, year and selected variables appear automatically (if fresh. It is our wish to now draw graph between the variables by simply selecting them in the desired axis. In the right side of the boxes, type, point type and specific color tools appear.
Load the observed file (prepared in .txt or notepad format with the same headers/parameter format as the simulation one) into the ApsimFile Reader of the observed component. Clicking on the XY plot will now display both simulated and observed data of the same variable and the same time period. Change in the type of chart, color, etc. can be adjusted as desired. vii) APSIM has a button on the main toolbar of the application to send the output file to Microsoft Excel.
To send an output file or multiple output files to Excel, just select them in the simulation tree and click the Excel button. Singh Page 32 Different ways of graphical presentation among the variables from output file to validation.
