Technical note: A sigmoidal soil water retention curve without asymptote that is robust when dry-range data are unreliable

Abstract. In a recently introduced parameterization for the soil water retention curve (SWRC) with sigmoid wet branch and logarithmic dry branch, matric potential at junction point of (hj) was fitting parameter, while that oven dryness (hd) derived from parameters. The latter is undesirable, especially if reliable data in range are limited. Therefore, an alternative presented which shape parameter α instead hd can be fitted or fixed. resulting relationship between hj such it prevents correct fits hj. Fortunately, expression found allows to replaced by as parameter. corresponding space well behaved has fewer internal bounds defined restraining relationships parameters than few available values literature line those according new expression. reformulated SWRC 21 soils shuffled complex evolution. paper gives main features accompanying open source code. curves fit well, except some clayey soils. A theoretical value performs wide simplifies earlier model based on known power-law very large.