Development of pedotransfer functions for a profile cone penetrometer

In this study, we illustrate how profile cone penetrometers PCP , can be used to measure . penetration resistance rapidly to define zones similar in cone index CI , which can be related to u , and ii to evaluate the sensitivity of parameters used in these functions. The data set represented soils formed in reworked silty loess overlying glacial till and ror lacustrine sediments. The global data set were grouped into subsets in terms of similar CIs. A horizontal hierarchical cluster analysis and a vertical point inflection method were used to derive cone index layer . profiles CILP1 to CILP5 . Variability of CI within CILPs was small and variability of CI among CILPs was large. Within each group, CI was regressed with soil physical properties to develop 2. pedopedotransfer functions. These were evaluated using the coefficient of determination R.A sensitivity analysis was executed to evaluate the relative importance of different parameters in the regression models. For the total data set, R 2 ranged from 0.35 to 0.48. Pedotransfer functions for the CILPs showed largest R 2 with 0.62 for CILP1, 0.76 for CILP2, 0.70 for CILP3, 0.63 for CILP4 and 0.98 for CILP5. Depth, r , clay content and u were variables with large predictive b power. Textural variables had strong predictive power in the top layers, CILP1 and CILP2. In CILP4, clay contents along with r and u were variables with large predictive power. In contrast, b the predictive power of r and u was strong in layers CILP3 and CILP5, whereas soil textural b