[01] Sabri Kanzari, National Institute of Research of Rural Engineering, Waters and Forests of Tunis, University of Carthage, Ariana, Tunisia. [02] Issam Daghari, National Institute of Agronomy, University of Carthage, Tunis, Tunisia. [03] Sana Ben Mariem, National Institute of Research of Rural Engineering, Waters and Forests of Tunis, University of Carthage, Ariana, Tunisia. [04] Riadh Ilahy, National Institute of Agronomic Research of Tunisia, University of Carthage, Tunis, Tunisia. [05] Samir Ghannem, National Institute of Research of Rural Engineering, Waters and Forests of Tunis, University of Carthage, Ariana, Tunisia. [06] Mourad Rezig, National Institute of Research of Rural Engineering, Waters and Forests of Tunis, University of Carthage, Ariana, Tunisia. [07] Béchir Ben Nouna, National Institute of Research of Rural Engineering, Waters and Forests of Tunis, University of Carthage, Ariana, Tunisia.

Soil hydraulic properties are necessary in numerous fields like hydrology, irrigation and numerical modeling of water flow in unsaturated soils. However, direct method to estimate these parameters are nonexistent. The approaches used to characterize soil hydraulic properties are often tedious. That's why several simpler methods were developed like the Beerkan method. The spatiotemporal variability of saturated hydraulic conductivity, (Ks) and the alpha parameter (α) of van Genuchten equation has been studied on an agricultural loamy-clay soil between 2015 and 2016 in a semi-arid area of Tunisia. The Beerkan infiltration method and its algorithm BEST were used to characterize the soil through the van Genuchten and Brooks and Corey equations. The totals of 121 measurements were made at each node of a 10×10 m grid. No significant differences in the results obtained in 2015 and 2016 were observed for saturated hydraulic conductivity, Ks and the alpha parameter α of van Genuchten equation. Also, it is suggested that both the Ks and α values were still better described by the lognormal distribution. The spatial patterns of hydraulic parameter variations seem to be temporally stabilized, at least within the agro-pedo-climatic context of the study. The one year time stability may be referred to the textural properties which remain constant in time and to the soil structural properties which are constantly renewed by the cyclic agricultural practices.

Soil Hydraulic Properties, Beerkan Infiltration Method, Spatiotemporal Variability, Loamy-clay Soil, Semi-arid Region

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