STUDY THE INFLUENCE OF SOIL MOISTURE AND PACKING INCREMENTAL LEVEL ON SOIL PHYSICAL AND HYDRAULIC PROPERTIES
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Date
14/07/2020
DOI
Open Access Location
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The Author(s), Massey University
Abstract
Reconstructed soil packing is an alternative for monolithic soil columns in lysimeter studies.
The excavated soil is packed in uniform layers to represent the natural soil conditions.
Reconstructed soil packing alters the physical properties, including bulk density and porosity,
thus can distort the hydraulic properties of the soil, so consistency of the method used is critical.
Therefore, the selection of a suitable packing method is imperative. This preliminary study
comes under the broad research programme: “developing and testing new fertilizer
formulations in lysimeters”. This work was aimed to study the effect of incremental packing
methods on the hydraulic properties of soil to select the best combination for testing fertilizers.
The selected soil matrix for this lysimeter study was composed of 10 cm topsoil and 30 cm
washed builders’ sand. For this study, four different soil packs were trialled in lysimeters with
the combination of two soil moisture conditions (dry/damp and wet) and two packing depth
increments (5 and 10 cm). The flow rate and saturated hydraulic conductivity were measured.
Subsequently, several pore volumes of water (around 5 – 6) was allowed to pass through the
soil column and the soil subsidence level was measured for each packing method. Both soil
moisture condition and packing increment level have influenced the flow rate and saturated
hydraulic conductivity of the soil matrix. The saturated hydraulic conductivity of the dry-5 cm,
dry-10 cm, wet-5 cm and wet-10 cm packing were 3.99, 6.70, 3.56 and 6.53 cm hr-
1
,
respectively. Soil subsidence was also influenced by both the soil moisture condition and
increment level. The highest soil subsidence was exhibited by dry-10 cm packing (13 mm) and
lowest by wet-5 cm (2 mm) (p<0.05). This preliminary study showed that both moisture
condition and increment level influence the soil hydraulic property and compaction level.
Further study needs to be conducted to understand the influence of soil moisture and
incremental level on other physical and hydraulic properties of soil packing.
Description
Keywords
Packing increment, moisture level, reconstructed soil packing, soil hydraulic property, soil subsidence level.
Citation
2020, pp. ? - ? (5)