This is update 62 of 17 August 2017.
A new page was entered on crop
sensitivity to shallow watertables with examples
for different crops in different countries. All
examples result from measurements in farmers' fields.
Since the first publication, in June 2002, download opportunities are given of computer programs SegReg, CumFreq, EnDrain, RainOff and Saltmod.
Download facilities of (1) a lecture note with applications of SegReg, CumFreq and RainOff and (2) an article on the energy balance of ground water (groundwater) flow belonging to EnDrain are also given.
Since then the web site was regularly updated and extended as follows.
UPDATE RECORD (the 56 updates before 2014 have been omitted)
In update 61 on 11 April 2017 examples of crop
tolerance to soil salinity measured in irrigated farm
lands were added in the new
On 21 April new pdf files were uploaded
with data on salt tolerance of crops determined in
On 26 April the CumFreq
program for probability distribution fitting was
adjusted to deal with zero data values, thanks to a
suggestion by Ivor Growns.
On 16 May the application for
partial regression was given
an F-test and additional graphics options.
On 10 July the rainfall-runoff
simulation model was given
a calculator for the computation of the reaction or
response factor (reservoir function) of agricultural
subsurface drainage systems with pipes or ditches.
In update 60 of 2 October 2016 the input menu of the SegReg program (for segmented regrssion analysis) and the CumFreq program (for cumulative frequency and probability distribution fitting) have been changed to facilitate more effective changes in the number of data. On 3 October the same was done with the RainOff program for rainfall-runoff modeling. On 11 November the CumFreq program was given the simple exponential distribution next to the generalized one at the request of Charles Tomkins. On 16 November the CumFreq program was updated again to include the usual normal and lognormal probability distributions omitting the optimization of mean and standard deviation. On 3 March 2017 the distribution of the evaporation over the various rootzone layers in the LeachMod program was refined leading to a small change in the salinity distribution over these layers.
In update 59 of 6 March 2016 the source code of software and programs, which were elaborated with Borland's Delphi 7, have been made available for free download on the source code page . On 7 April 2016 the LeachMod program for soil salinity simulation has been updated and the initial soil salinity can be given for 3 rootzone layers separately instead of 1 value for the whole rootzone. On 6 July 2016 the LeachMod model was given a calibration and a verification mode. A LeachMod version for two neighboring areas is in development. There appears te be a large demand for such type of apps. On 9 July 2016, a partialized segmented regression program was introduced by the name of PartReg instead of SegReg with the purpose to detect the longest horizontal trendline aiming at defining tolerance levels more percisely.
In update 58 of 25 May 2015 The SaltMod model for seasonal calculations of soil salinity and watertable depth under different hydrologic and soil conditions was given an extended version for a larger number of crop rotation types. Also, a SaltMod version was developed with a modernized user interface for data input. The SahysMod model, based on SaltMod, but much larger as it is based on a polygonal network with a groundwater model, was also given a version with a larger number of crop rotation types. All new versions can be made available on request. On 11 July 2015 the LeachMod model, based on SaltMod but somewhat simplified thus enabling shorter time intervals, has been updated in the sense that a more rigorous data check was introduced.
In update 57 of 7 August 2014 new software was added to the suite of computer programs. It concerns PolySalt a condensed version of SahysMod permiting monthly calculations of soil salinity and groundwater level in a polygonal network with a ground water model with monthly input changes instead of annual. It can be seen as the SaltCalc model applied to each polygon separately but hydrologically connected in the underground. On 24 August 2014 the guided network construction in the Sahysmod and PolySalt models was improved. On 11 September a new version of SaltCalc was made with an updated user interface for both input and output data handling. On 13 September the CumFreq program for cumulative frequency analysis and probability distribution fitting was given an additional feature: the twice generalized logistic probability distribution.