Influence of soil structure on sulfate leaching from a silt loam

Abstract

The influence of soil structure on sulfate leaching from a silt loam soil was assessed by comparing the results of leaching experiments conducted using undisturbed soil monolith lysimeters and re-packed soil columns. A pulse application of sulfate solution was leached through both soil systems under non-ponded infiltration conditions. Breakthrough curves (BTCs) from the undisturbed soil lysimeters were poly-modal compared with the uni-modal curves observed in re-packed column experiments. The poly-modal BTC is considered to result from sulfate leached through isolated porosity regions within the undisturbed soil monolith. Sulfate leaching rates were faster through the undisturbed soil lysimeters and this was attributed to solute transport through the natural soil macropore system, which is retained in the undisturbed soil but lost in the repacked soil columns. Leaching through soil macropores therefore can result in considerable losses of sulfur from silt loam textured soils.

Distribution, transformations and recovery of urinary sulphur and sources of plant-available soil sulphur in irrigated pasture soil–plant systems treated with35sulphur-labelled urine

“…Nguyen & Goh 1991) in this soil. The presence of labelled-S at a depth of 900 mm on D27, even in Treatment 1, where there was no estimated water drainage beyond 0-450 mm during the D0-D27 period, suggests that labelled-S from 35 S-labelled urine preferentially moved through cracks and macropores in the soil profile (McLay et al 1991(McLay et al , 1992. Although in all treatments, labelled-S was present at depths below the major rooting zone on D27, D75 Bennett and Webb (1985).…”

Impacts of zeolite, alum and polyaluminum chloride amendments mixed with agricultural wastes on soil column leachate, and CO2 and CH4 emissions

“…The use of disturbed soil columns to measure leaching and transport of contaminants through soils is a well-established laboratory method (e.g. Jin et al, 1997;Enell et al, 2004;Dontsova et al, 2006) and while macropore structure of intact soils is disturbed during the repacking process (McLay et al, 1992), soil columns nevertheless facilitate the investigation of contaminant transport in a homogenous soil under controlled conditions (Murphy, 2007). Previous studies have examined the potential of slurry amendments to mitigate leachate losses and GHG emissions from land applied pig and dairy slurries (O' Flynn et al, 2013;Brennan et al, 2015), but currently there are no data available to evaluate and compare the effectiveness of zeolite used in combination with chemical amendments to mitigate leaching losses of N, P and C, and emissions of CO 2 and CH (in storage and upon application to land) when applied to dairy and pig slurries and dairy soiled water (DSW).…”

An overview of the New Zealand sulphur cycling model for recommending sulphur requirements in grazed pastures

“…Although some of these limitations have already been identified (Sinclair 1983;Sinclair et al 1985;, an overview of these limitations in light of recent research progress (e.g., McCaskill & Blair 1988;Heng 1991;Phimsarn 1991;Sakadevan 1991;McLay et al 1991McLay et al , 1992Watkinson et al 1991;Nguyen & Goh 1992a, b) has not been carried out. In addition, parameters used in other S cycling models developed elsewhere for grazed pastures are also being examined as to their applicability for incorporation into the MAF S model.…”