Fitting water retention data using Excel

Fitting the nonlinear van Genuchten (1980) equation using Excel Solver Link to the worksheet: https://github.com/leaot/water-retent... van Genuchten, M.T. (1980) A Closed-Form Equation for Predicting the Hydraulic Conductivity of Unsaturated Soils. Soil Science Society of America Journal, 44, 892-898.