Verification of Appropriateness of Selected Pedotransfer Functions for the Basic Use in Agriculture of the Czech Republic

Abstract

Soil is a huge reservoir of water used by plants in periods without precipitation and signifi cantly aff ects the hydrological balance of any territory. To evaluate the hydrological balance of any piece of the land given, it is therefore necessary to carry out the analysis of the hydro-physical conditions. To speed up and simplify the determination of basic hydro-physical properties of soil man developed and began to use the so-called pedotransfer functions (PTF). Comparison of domestic and foreign works, however, faces problems such as the defi nition of available water supplies in diff erent countries. In the research project "Specifi cation of the available supplies of nitrogen and water in the soil profi le and determining the eff ective depth of crops' roots" we have dealt with the selection of suitable pedotransfer functions necessary for basic agricultural production with the requirement of minimal amount of input data. For our research we chose several PTFs developed and used in the Czech Republic for a long time, with a minimum of input data, and several new PTFs from foreign authors with greater correlation, but also a greater need of input data, and we compared each other. The best correlation between values and the pedotransfer function for the fi eld water capacity and for the wilting point seems to be the PTF according to Tomasella and PTF according to Batjes. Pedotransfer function according to Váša, in terms of volume of input data, appears better.

Simple and Cost-Effective Method for Reliable Indirect Determination of Field Capacity

“…Vlček and Hybler [19] conducted a rather extensive study to test different simple regression-type PTFs for estimating FC and WP, including the equations by Váša. Among the tested models of PTFs, the equations by Váša showed the poorest performance for both soil moisture constants (R 0.89 and 0.81, respectively).…”

“…It should be noted that the word "constant" can be misleading as it implies invariant behavior of the soil pore system. In Central Europe, regression equations for estimating FC and WP from a fine particle size fraction (FPSF; soil particles < 0.01 mm) have been established [13] and are still in use [19,20]. Although there are different varieties of PTFs for estimating the soil water retention curve or just its important points, such as FC and WP [15][16][17][18], they are rarely used by researchers and decision makers for practical applications.…”