Practical and validated methods to measure anisotropy of saturated, Ks, or field‐saturated, Kfs, soil hydraulicconductivity on a single soil sample are still lacking. The objective of this investigation was to test factors affecting anisotropymeasured in a sandy‐loam soil by the constant‐head laboratory permeameter and the modified cube method. The ratio, RK,between the conductivity results obtained with a long (6 h) and a short (0.5 h) duration run varied from a minimum of 0.29to a maximum of 0.88 with the considered experimental procedure, differing by both the employed constant‐head device(Mariotte bottle, siphon) and the initial soil water content (unsaturated, saturated). Maximum time stability was detected witha siphon and an initially saturated soil sample, suggesting that soil alteration at the surface may influence the measuredconductivity, and more reliable anisotropy measurements have to be expected for Ks than Kfs. A short‐duration run carriedout with a siphon and a calcium solution was also suggested for laboratory determination of Ks anisotropy since morerepresentative results were obtained for a single cube of soil (i.e., horizontal, Kh, to vertical, Kv, conductivity ratio varyingfrom 1.78 to 1.82 with the measurement sequence) as compared with the ones associated with using tap water (ratio varyingfrom 1.24 to 2.09). The Kh/Kv ratio varied between 1.80 and 2.81 on two dates (April and July 2009) differing by the soil watercontent at the time of sampling (close to field capacity; lower than the permanent wilting point, respectively), and a significanttemporal variability was only detected for Kv. Therefore, temporal variability of Ks anisotropy cannot be predicted bymeasuring one‐dimensional Ks.
|Numero di pagine||8|
|Rivista||Applied Engineering in Agriculture|
|Stato di pubblicazione||Published - 2011|
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