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ARS Home » Pacific West Area » Riverside, California » Agricultural Water Efficiency and Salinity Research Unit » Docs » Model » WATSUIT Model

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The demo version of the program, and examples and manual,
can be downloaded from the software download area.

Year: 1991
Version: 1.0


WASUIT is a computer program which predicts the
  • Salinity
  • Sodicity
  • Toxic-solute concentration
of the soil-water within a simulated crop root zone resulting from the use of a particular irrigation water of given composition and at a specified leaching fraction. It can be used to evaluate the effect of a given salinity level (or solute concentration) on crop yield and of a given sodicity level on soil permeability.

System Requirements:

WATSUIT is written in Standard FORTRAN 77 and requires ANSI.SYS installed in your CONFIG.SYS file (i.e., DEVICE=C:\DOS\ANSI.SYS). The ANSI.SYS screen commands are used to clear your computer screen. If for some reason you do not have ANSI.SYS, the program will still run but will not your screen will not be cleared. MS-DOS 2.0 or later operating system and standard IBM 360 or 1.2 kbytes diskette drives are required.

Execution of the Program:

WATSUIT.EXE - executable file for IBM PC or compatibles without the numerical co-processor

  • At DOS prompt, type: WATSUIT (return)
WATS87.EXE - executable file for IBM PC or compatibles with the numerical co-processor
(8087, 80287, or 80387)
  • At DOS prompt, type: WATS87 (return)


Select to send output to the screen or to a disk file
  • ENTER "S" for screen
  • ENTER "D" for disk
    • If you enter "D" you must next enter a filename to store the output. This filename must be no longer than 8 characters and 3 characters for the extension (8.3 format: A:\filename.ext)
  • ENTER "Y" for CaCO3 saturation, "N" for no CaCO3 saturation
    • CASE ID limited to 8 Alpha-numeric characters
  • ENTER Solute Concentrations of irrigation water
    • Enter CA, MG, NA, K, CL, ALK, and SO4
    • Concentration can be separated by commas or (returns)

    NOTE: If there is an cation/anion imbalance, the program will calculate the difference. If the difference (sum of cations minus sum of anions) is positive, it will add the difference to the Anion that has not been initialized in the order of (Cl, SO4, ALK), if all are initialized, difference will be added to Cl. If difference is negative (i.e., sum of anions > sum of cations) program will subtract the absolute difference in the order of (CL, SO4, ALK). If no one anion can handle the subtraction, program stops.

  • ENTER "Y" for yes or "N" to indicate you wish to enter amendments
    • ENTER "Y" or "N" for each amendment(s) desired
      • H2SO4 ?
      • 01 meq CaSO4 ?
      • 02 meq CaSO4 ?
      • 05 meq CaSO4 ?
      • 10 meq CaSO4 ?
      • 20 meq CaSO4 ?
      • User Defined CaSO4 ?
        If "Y" is entered for User Define CaSO4,
        user must enter the desired meq of CaSO4
  • ENTER "Y" for yes or "N" for no to indicate the desired leaching fractions.
    • ENTER "Y" or "N" for leaching fractions
      • 05 ?
      • 10 ?
      • 20 ?
      • 30 ?
      • 40 ?
      • User Defined Leaching Fraction ?
        If "Y" is entered for User Define Leaching Fraction,
        user must enter the desired leaching fraction in decimal form.

Printing Results to a Disk file:

  • Technique #1
    • Hit: CTRL-P (turn printer on)
    • Type: filename (return)
    • Hit: CTRL-P (turn printer off)
  • Technique #2
    • At the DOS prompt, TYPE: PRINT filename (return)
  • PRINT is a basic DOS program
    which should be present on your DOS disk or DOS sub-directory.
  • If you DOS sub-directory is not on your path in your autoexec.bat file, you will need to
    type in the full pathname above. i.e. TYPE: c:\dos\print filename (return)

Printing Results to the Screen:

  • Press CTRL-P at beginning of session all results will print on screen and printer
  • Press CTRL-P turns printer off