Comparison between Soil-Water Characteristic Curves based on filter paper method and grain-size distribution/volume-mass prediction: An evaluation of input data stemmed from hydrometer and Cilas grain-size analyser

The current paper aims to present a comparison between soil-water characteristic curves based on the filter paper method and on a volume-mass estimation. Additionally, this research consists in comparing grain size distributions by sieving/hydrometer and by sieving/Cilas (particle-size analyser model 1092), when it comes to determining the soil-water characteristic curves by a volume-mass prediction on the Soil Vision software. As materials, were used two sets of colluvial soils sampled at the Campus Quinta do Paraiso - Centro Universitario Serra dos Orgaos (UNIFESO), Teresopolis - Brazil. The results showed that the soil-water characteristic curves related to the filter paper method or grain size distribution estimation are different. However, the tests performed by sieving/Cilas are more efficient than the results based on sieving/hydrometer, concerning its uses as input data for soil-water characteristic curves estimations. In conclusion, even considering the estimation method was not able to depict the same results such as obtained by the filter paper method, the use of Cilas is a procedure that can improve the quality of the predicted soil-water characteristic curve.