EGU23-12011
https://doi.org/10.5194/egusphere-egu23-12011
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

A bimodal extension of the ARYA&PARIS approach for predicting hydraulic properties of structured soils

Shawkat Basel Mostafa Hassan1, Giovanna Dragonetti2, Alessandro Comegna1, Asma Sengouga1, Nicola Lamaddalena2, and Antonio Coppola1,3
Shawkat Basel Mostafa Hassan et al.
  • 1University of Basilicata, School of Agricultural, Forestry, Food and Environmental Sciences, Potenza, Italy (shawkat.hassan@unibas.it)
  • 2CIHEAM Bari - Mediterranean Agronomic Institute of Bari, Bari, Italy
  • 3University of Cagliari, Dept. of Chemical and Geological Sciences, Cagliari, Italy

A new pedotransfer function (PTF) was developed based on the Arya and Paris (AP) approach to obtain Water Retention (WRC) and Hydraulic Conductivity (HCC) curves. The AP approach obtains the unimodal WRC from the Particle-Size Distribution (PSD). The proposed PTF is an extension of AP approach by incorporating the Aggregate-Size Distribution (ASD) to include the inter-aggregate pores (macropores) retention, and thus obtain the bimodal WRC. A bimodal porosity model was developed to specify the ratios of the matrix and the macropores in the overall soil porosity. Kozeny-Carmen equation was utilized to obtain the saturated hydraulic conductivity, K0, from the bimodal WRC behaviour near saturation. Then, Mualem model was applied to obtain the full HCC. To calibrate the proposed PTF, soil physical and hydraulic properties were measured from a 140-ha irrigation sector in “Sinistra Ofanto” irrigation system in Apulia Region, South Italy. Hydraulic properties came from infiltration experiments. Infiltration data were fitted using bimodal and unimodal hydraulic properties by an inverse solution of Richards Equation. The scaling parameter of the proposed PTF, αAP, was calibrated using the measured bimodal hydraulic properties. A similar calibration was carried out for the sake of comparison, in which the αAP of the classical unimodal AP was calibrated using the unimodal hydraulic properties. The proposed bimodal AP (bimAP) PTF significantly improves the predictions of the mean WRC parameters, K0 and the entire HCC, compared to the classical unimodal AP (unimAP) PTF. In addition, compared to unimAP, bimAP allows to reproduce the statistics of the hydraulic parameters (e.g., the variance) similar to those obtained from field measurements. Finally, Multiple Linear Regression (MLR) was applied to study the sensitivity of bimodal αAP to the soil textural and structural properties and the results confirmed the significant predictive effects of soil structure.

How to cite: Hassan, S. B. M., Dragonetti, G., Comegna, A., Sengouga, A., Lamaddalena, N., and Coppola, A.: A bimodal extension of the ARYA&PARIS approach for predicting hydraulic properties of structured soils, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-12011, https://doi.org/10.5194/egusphere-egu23-12011, 2023.