Pedotransfer functions for the soil water retention and soil resistance to penetration curves

Pedotransfer functions (PTFs) are useful tools to obtain estimates of soil physical properties such as the soil water retention curve (SWRC) and the soil resistance to penetration curve (SRPC), which are important inherent soil properties and difficult to measure. Most of the studies in the literature report PTFs only in relation to SWRC estimates. An important and necessary advance in this research area would be the development of PTFs for a simultaneous estimation of the SWRC and SRPC, which is the objective of this paper. An area with wide variation in soil texture was selected where 180 samples were collected for the measurement of SWRC, SRPC, bulk density, soil texture and organic carbon content. Both SWRC and the SRPC were successfully estimated with the coefficient of etermination (R-2 > 0.9). Clay content was the most important soil property to determine the PTFs and its effect on SWRC and SRPC was demonstrated.