We can plot USSL diagram using simple Excel also, EC vs Na% and then divide them into Unstable, Doubtful to Unstable, Good to Permissible and other catergoris
Hi, you can use the AquaChem software, i think it is licensed, but you can download a free trial. Use the template that is within the software to load your data, and then go to the Tab "Plots" > "New" and search "Wilcox", this will plot your data in a EC vs SAR (sodium adsorption ratio) diagram.