Methods for saturated soil hydraulic conductivity determination in different soils

Abstract

The article describes a study about the differences between three methods used to measure saturated soil hydraulic conductivity (K₀) in four sites with different textural classes and soil managements. The completely randomized statistical design was used in a 3 x 4 factorial scheme, with four replicates. The three methods used were: (i) constant head permeameter with soil samples of undisturbed structure (USS), (ii) constant head permeameter with soil samples of disturbed structure (DSS) and (iii) Guelph permeameter (GP). The four sites in which the methods were performed were: clay soil in fallow (CSF); clay-sandy soil under virgin forest (CSVF); clay soil under sugar-cane crop (CSC); and sandy loam soil under horticulture (SLH). At the same time, measurements with the GP method, varying the water head from 0.02 to 0.16 m, were performed in eight replicates. In the sites with soils with higher clay content (CSF and CSC), there was significant difference between GP and the other two methods, allowing the use of DSS, since there was no significant difference between this method and USS. In the sites with lower clay content (CSVF and SLH), however, there was significant difference between the three methods; DSS overestimated K₀ and PG underestimated K₀ when USS is taken as the standard method. When comparing the different water heads used in the GP method, no significant difference was detected between them.