Dry sieving analysis of soil by vibratory sieve shaker: modification and optimization

Abstract

This study performs a methodical experiment on adaptation and unification of soil dry sieving analysis. The analysis is based on the Savvinov dry sieving method that uses 0.5-1.5 kg air-dried soil samples which are passed through the 10, 7, 5, 3, 2, 1, 0.5, 0.25 mm sieves. The studied soils are silt loam Eutric Retisol and Haplic Chernozem. From each object, 50 kg of fresh soil was sampled from the plow layer (lm2 area). Air-dried soil subsamples of 500 ± 0.5 g were used for analysis, clods bigger than 50 mm were gently crushed by pestle with rubber tip. The sieving parameters were the following: 50 Hz vibration frequency - 3000 rpm (depend on current), from 0.5 to 2.5 mm vibration amplitude and from 0.5 to 5 minutes sieving time. Sieve shaker mechanical work (J) was calculated for each mode. The data approximation was carried out by means of the asymptotic regression function. An optimal dry sieving mode was defined for each soil: Eutric Retisol - 1 mm vibration amplitude during 1 minute, Haplic Chernozem - 2.5 mm vibration amplitude during 2 minutes. In the case of sandy soils dry sieving doesn't require much effort. Therefore, in this experiment only fine macrostructure soils were selected (11-16 % < 2 um clay by laser diffraction method). As a result, the unified dry sieving mode of vibratory sieve shakers was developed which is applicable for all studied soils: 2.5 mm vibration amplitude during 2 minutes and 50 Hz frequency when 500 g air-dried soil sample is used.

Keywords

• soil structure
• aggregates
• fractionation
• structural stability
• erosiveness