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Avoiding the point of no return: Maintaining infiltration to remediate saline-sodic Vertosols in high rainfall environments

Citation

Das, BT and Menzies, NW and Dalzell, SA and McKenna, BA and Kopittke, PM, Avoiding the point of no return: Maintaining infiltration to remediate saline-sodic Vertosols in high rainfall environments, Agricultural Water Management, 270 Article 107725. ISSN 0378-3774 (2022) [Refereed Article]


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DOI: doi:10.1016/j.agwat.2022.107725

Abstract

Saline-sodic soils are often too saline and alkaline for plant survival. These soils are prone to dispersing and eroding after high rainfall events when salinity is reduced before the sodicity. Cost-effective and water efficient methods are needed to leach salts while maintaining sufficient ionic strength of the soil solution. We tested the ability of gypsum, both alone and combined with elemental sulfur and organic matter to remediate the upper 15 cm of a strongly saline-sodic alkaline Vertosol when leached with deionised water in repacked columns. Prior to leaching, all amendment combinations reduced soil alkalinity by 80% and dispersion by 47% by displacing exchangeable sodium (Na). After leaching with 600 mm of deionised water, electrical conductivity of the soil solution (ECss) decreased from an average of 38-4.8 dS m-1 at 8 cm depth. Importantly, structure was maintained in all amended soils, despite this decrease in ECss. In contrast, for the control treatment, there was a concomitant loss of soil structural stability as EC decreased. This decrease in stability also occurred in the subsoils of all treatments (which were not amended) because the applied calcium (Ca) precipitated before it could be leached to remediate the deeper layers. This study demonstrated that it was critical to first apply amendments as deep in the soil profile as possible to prevent the development of a non-saline sodic soil. Leaching the soil with low ionic strength water removed excess soluble salts from the plant root zone. We estimated that > 300 mm of water (rainfall or irrigation) was required to leach through the root zone to ensure a suitable soil profile for establishing of salt tolerant pioneer species such as Rhodes grass (Chloris gayana Kunth).

Item Details

Item Type:Refereed Article
Keywords:alkaline, dispersion, gypsum, organic matter, sodium adsorption ratio, sulfur
Research Division:Environmental Sciences
Research Group:Soil sciences
Research Field:Soil chemistry and soil carbon sequestration (excl. carbon sequestration science)
Objective Division:Environmental Management
Objective Group:Terrestrial systems and management
Objective Field:Soils
UTAS Author:Das, BT (Ms Bianca Das)
ID Code:150224
Year Published:2022
Deposited By:TIA - Research Institute
Deposited On:2022-06-02
Last Modified:2022-08-01
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