Among salinity tolerance studies the piecewise linear method has been widely used to characterize crop response. The two parameters of this method have been determined for different species and compiled in tables by different authors. However, this information is not directly compatible with an allometric function proposed by Misle and Kahlaoui (2015), which allows determining three mathematically characteristic points of the salinity response curve, among other advantages. In this work, a conversion way of the parameters of the piecewise linear function into the parameters needed by the allometric equation is presented, using data of vegetable crops, including in addition, the estimation of two of its characteristic points: the first 1:1 slope point and the inflection point. 31 parameter determinations were performed for 29 vegetable species. This particular way to fit this equation accurately describes the salinity crop response found in classic tables, starting only from the two parameters of the linear method. The scope of this particular application of the allometric function is discussed.