Developing Pseudo Continuous Pedotransfer Functions for International Soils Measured with the Evaporation Method and the HYPROP System: I. The Soil Water Retention Curve

Abstract

Direct measurements of soil hydraulic properties are time-consuming, challenging, and often expensive. Therefore, their indirect estimation via pedotransfer functions (PTFs) based on easily collected properties like soil texture, bulk density, and organic matter content is desirable. This study was carried out to assess the accuracy of the pseudo continuous neural network PTF (PCNN-PTF) approach for estimating the soil water retention curve of 153 international soils (a total of 12,654 measured water retention pairs) measured via the evaporation method. In addition, an independent data set from Turkey (79 soil samples with 7729 measured data pairs) was used to evaluate the reliability of the PCNN-PTF. The best PCNN-PTF showed high accuracy (root mean square error (RMSE) = 0.043 cm3 cm−3) and reliability (RMSE = 0.061 cm3 cm−3). When Turkish soil samples were incorporated into the training data set, the performance of the PCNN-PTF was enhanced by 33%. Therefore, to further improve the performance of the PCNN-PTF for new regions, we recommend the incorporation of local soils, when available, into the international data sets and developing new sets of PCNN-PTFs.

Prediction of water retention properties of Syrian clayey soils

“…Whatever the soil texture and more markedly in semiarid and arid areas, it is important to ascertain the water retention properties of soils in order to manage the water supply and consequently crop growth appropriately (Gaiser et al, 2000). To accomplish this, pedotransfer functions that enable prediction of the water retention properties of soils have therefore been developed (e.g., Bouma & Van Lanen 1987;Wösten et al, 1999;Al Majou et al, 2008a& 2008bOstovari et al, 2015;Kalumba et al, 2020;Singh et al, 2020;Xu Xu et al, 2021), with several studies focusing on soils of semi-arid and arid areas (Tóth et al, 2012;Khlosi et al, 2012Khlosi et al, & 2016Al Majou et al, 2018;De Paepe et al, 2018;Santra et al, 2018;Dharumarajan et al, 2019;Soleimani et al, 2020). At the same time, some studies aimed at a better understanding of the water retention properties of soils according to the characteristics of their clay minerals but the validity of the results for soils of semi-arid and arid areas remains unclear (Gaiser et al, 2000;Moret-Fernandez et al, 2013).…”