Use of nonlinear regression and nonlinear mathematical programming in the formulation of substrate mixtures for soil-less culture - a review -

With respect to four inorganic and organic substrates - tezontle (volcanic rock), per- lite, peat and coir - we studied the relevant physical and chemical properties of mix- tures of two of these substrates. A nonlinear regression model was used to analyse the physical properties of each possible mixture. Finally, a methodology is proposed for formulating mixtures of substrates as a deterministic nonlinear mathematical programming problem.