Automatic Sieve-Shaker for Determining Soil Aggregate Stability and Dimensional Distribution Using a Vertical Oscillation System

The soil aggregate stability is determined generally by sifting the soil samples in water using a sieve-shaker (wet sieving). The Author has developed an original model of automatic sieve-shaker using a vertical oscillation system to the aim of an its possible use to determine the soil aggregate stability and dimensional distribution. The purpose of this note is to describe the construction and performance of the prototype currently used in the Laboratory for the Soil Structure Study of the ISAFOM – CNR. The proposed sieve-shaker, with the introduction of some innovations (protected by Italy Patent 0001332102), realizes the submersion and levelling of the soil samples using a lifter to support the containers with the water. With 6 workplaces it allows to process simultaneously up to 6 soil samples according to different test cycles. By means of the control panel it is possible to set up various determinations with the stroke of 3 cm and the oscillation frequency from 4 up to 80 oscillations per minute. The performance of the proposed sieve-shaker was verified with a technical test to verify the performance of the 6 workplaces to oscillation speed increasing up to 60 oscillations per minute and an agronomic test. The results have been submitted to analysis of variance considering the plots of the field from which have been taken the samples for repetitions and the six workplaces of the proposed sieve-shaker for experimental theses. The differences between the various workplaces have not been significant. This demonstrates that the behavior of the various workplaces is uniform. The dispersion in water at constant shaking time and increasing oscillation speed has evidenced a very significant inverse relation between the index of aggregate stability in water (IASW) and number of oscillations per minute. This result demonstrates a constant performance of the proposed sieve-shaker to varying of the oscillation speed. The agnonomic test has demonstrated that the various workplaces of the proposed sieve-shaker do not present a significant difference of the performance and neither interactions with the treatments. The proposed automatic sieve-shaker presents the advantage to be used both for the routine measures, with reference to ISO/TC 190/SC 5/WG 8 method, and for the research specific purposes by varying the oscillation frequency and shaking time.