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Effectively managing salt affected irrigated lands and judicially using irrigation water of marginal salinity quality requires understanding the interactions among many inputs. They include soil salinity, crop salt tolerances, soil physical properties, irrigation water quality, irrigation management, water table depth and quality, climatic factors and crop yield. Visualizing the simultaneous interactions among this many factors over a cropping season extends beyond the capacity of the human mind.

An interactive computer program was developed to simulate the interactions among the above factors. It shows how changing one factor impacts the outcome of the other factors for a single growing season. The user selects a climate, a crop, and soil characteristics from menu lists, and then sets the water table depth and quality, irrigation (river or well) water quality and then develops an irrigation schedule. On execution, the relative yield reductions due to over irrigation, under irrigation, and salinity, water table rise or fall and surface runoff are shown numerically for the growing season. Soil water content, soil salinity, water table depth changes and rain and irrigation events during the season are also shown graphically.

This is an educational tool designed to teach the concepts of salinity and irrigation management and IS NOT an irrigation scheduling program nor a management tool. Two versions have been developed, one using metric units, southern hemisphere growing seasons and Australian terminology, and a second using northern hemisphere growing seasons, with units and terminology currently used in US irrigated agriculture. An option in the US version also allows use of metric units.

The SWAGMAN acronym and the SWAGMAN-Whatif program copyrights are owned by Commonwealth Scientific and Industrial Research Organization (CSIRO) of Australia. The SWAGMAN acronym is not to be used for other programs.


SWAGMAN v1.5 from 1994 - Downloadable from this site, but no longer under active development.
To use:

1. Create a new directory, copy WHAT15-A.EXE into it, and run WHAT15-A.EXE. This expands the files compressed inside WHAT15-A.EXE.
2. If you get an error stating you've exceeded your license, delete the file USERLOG.RND.
3. Run WHATIF.EXE. Press Enter to get past the graphic splash-screen logo, the press Escape after reading the disclaimer.
4. To leave the program, go to the File menu and choose Quit.



The SWAGMAN page at CSIRO -

Meyer, W.S. and Robbins, C.W. and Prathapar, S.A. (1995) SWAGMAN-Whatif Software and User Guide. CSIRO, Griffith, NSW, Australia.

Meyer, W.S. and Robbins, C.W. and White, R.J.G. (1995) SWAGMAN-Saltimeter. Charles Start University, Wagga-Wagga, NSW, Australia.

Robbins, C.W. and Meyer, W.S. and Prathapar, S.A. and White, R.J.G. (1995) SWAGMAN-Whatif, an interactive computer program to teach salinity relationships in irrigated agriculture. Journal of Natural Resources and Life Sciences Education. 24:150-155. -

Robbins, C.W. and Meyer, W.S. and Prathapar, S.A. and White, R.J.G. (1991) Understanding salt and sodium in soils, irrigation water and shallow groundwaters: A companion to the software program SWAGMAN-Whatif. Water Resources Series No. 4. CSIRO, Canberra, Australia. 24 pp. -

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