List of files on the distribution diskettes.

REQUIREMENTS

To run the CERES-Wheat model, you must have the following:

IBM PC or compatible with at least 256K RAM Memory DOS (Disk Operating System) 2.0 or higher.

SYSTEM PREPARATION

A change must be made to a DOS file, CONFIG.SYS, in order to run the model. The CONFIG.SYS file must have a FILES=20 statement to run the model. By running the procedure described below, a CONFIG.SYS file will be created if one does not exist. If a CONFIG.SYS file does exist, it will be altered by adding the FILES=20 statement. If a CONFIG.SYS file does exist and has the FILES=20 statement, then proceed to "Running the Model". If your DOS files are on diskette and you have a single disk drive, refer to the following section "Preparing A Single Drive System". If your DOS files are on diskette and you have two disk drives, refer to the following section "Preparing A System With Two Drives." If your DOS files are on a hard disk, refer to the section "Preparing A Hard Disk System".

Preparing a Single Drive System

Using your DOS diskette, make a backup copy of your DOS diskette. With the DOS diskette in A:, type "DISKCOPY A: A:" at the A> prompt. When instructed, place a blank diskette in drive A:. After completing the copy, place the original DOS diskette in a safe place and use the backup copy. Be sure the backup DOS diskette is not write-protected. Place the diskette labeled " " in drive A: and type "CHANGE" at the A> prompt. When instructed, place the backup copy of DOS in drive A:. When you receive the A> prompt, reboot your system by placing the backup copy of DOS in drive A: and pressing the keys <CTRL>, <ALT>, and <DEL> at the same time. Use the backup copy of DOS to boot your system each time. Continue now to the section "Running the Model".

Preparing a System With Two Disk Drives

Using your DOS diskette, make a backup copy of your DOS diskette. With the DOS diskette in A: and a blank diskette in drive B:, type "DISKCOPY A: B:" at the A> prompt. After completing the copy, place the original DOS diskette in a safe place and use the backup copy. Be sure the DOS diskette is not write-protected. Place the diskette labeled " " in drive A: and the DOS diskette in drive B:. At the A> prompt, type "CHANGE". When you receive the A> prompt, reboot your system by placing the backup copy of DOS in drive A: and pressing the keys <CTRL>, <ALT>, and <DEL> at the same time. Use the backup copy of DOS to boot your system each time. Continue now to the section "Running the Model".

Preparing a Hard Disk System

With your hard disk at the subdirectory where the COMMAND.COM file is, place the diskette labeled " " in drive A:. At the A> prompt, type "CHANGE". When you receive the A> prompt, reboot your system by pressing the keys <CTRL>, <ALT>, and <DEL> at the same time. Continue now to the section "Running the Model".

Running the Model

Before running the model, make a backup copy of the diskette labeled "CERES-Wheat Model". The system should be rebooted if you have not already done so. Place the backup diskette in drive A:, making sure it is not write-protected. At the A> prompt, type "WHEAT". The following screen will appear:

After pressing return, a list of experiments to be simulated comes up on the screen:

Choose a selection. If you do not choose a selection (hit return), the default (Experiment 1) will be chosen. After a selection has been made, a list of available treatments for that experiment appears:

If you do not choose a treatment, the default (Treatment 1) will be chosen. After choosing a treatment, a list of run-time options comes up:

Choosing option 0 will run the simulation using all the input data in its existing form. Option 1 enables alteration to the frequency of the output for crop growth (Output File 2), water balance (Output File 3), and nitrogen balance (Output File 4). The default setting is, as shown below, seven days:

Using Option 1, the output frequency for these three output files can be altered. Option 2 will produce the following screen:

Option 2 enables modification of almost all of the input parameters interactively. A word processor is not needed to pose "what if" questions. When any option between 1 and 9 is chosen, further menus appear to help modification of the input data. Each of these menus features a terminator enabling return to the main selection menu.

Option 1 of the interactive modification menu allows the planting date to be changed:

Option 2 of the menu allows the plant population to be changed:

Simulation of nitrogen balance can be switched off or on using Option 3:

Simulation of nitrogen balance can also be switched back on using

Option 3:

Irrigation data can be added or modified using Option 4. The method of irrigation can also be changed:

The user would then choose Option 2 of Option 4 to add data to create a field schedule. Fertilizer data can be modified or added using Option 5:

The changes can then be viewed:

Option 6 allows a choice of a new variety. All current varieties available are printed out and then a choice can be made of a new variety. For the purposes of this example, only the first and last screens of Option 6 are shown:

A new variety can be created and used for the simulation only or can be written back out to the existing genetics coefficient file:

Option 7 enables selection of a different soil, as seen below :

The following parameters can be modified or simply looked at using Option 2 of Option 7:

Layer data can also be modified or viewed using Option 2 of Option 7:

Note that a "0" was entered at how many layers you want to modify, so as to check or "view" the parameter OC. Different weather data can be chosen using Option 8. Please note that the weather data chosen should have the same dates as the experiment :

Soil profile parameters can be checked and/or modified using Option 9:

The soil profile parameters can be viewed or modified as previously shown with Option 7. Soil moisture can be initialized to a percentage of whole profile storage by choosing Option 2 of Option 9:

Crop residue parameters can be modified using Option 3 of Option 9:

Option 10 of the interactive menu displays key input data on the screen for checking prior to running the simulation. Option 11 terminates data modification and runs the simulation. Option 12 terminates data modification, abandoning all previous changes, and returns back to the choosing an experiment menu. During the simulation run, certain error messages may appear if a file is not in the correct format or if data is missing. Below are some examples of possible error messages: