Effect of applied potassium concentration on clay dispersion, hydraulic conductivity, pore structure and mineralogy of two contrasting Australian soils

Marchuk, Serhiy and Marchuk, Alla (2018) Effect of applied potassium concentration on clay dispersion, hydraulic conductivity, pore structure and mineralogy of two contrasting Australian soils. Soil and Tillage Research, 182. pp. 35-44. ISSN 0167-1987

Abstract

Re-use of industrial and agricultural wastewater for irrigation can increase the concentration of potassium ions in soil solution and affect soil structural stability. However, investigations of clay dispersion have traditionally focused on soils with high exchangeable sodium. The objective of this study was to quantify the effects of potassium application on physical, chemical and mineralogical properties of two contrasting soils from South Australia. This work combines traditional soil and clay analysis methods with a range of additional techniques, including, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and modeling for characterizing and quantifying the movement of different forms of potassium in soil. In laboratory studies, soils were treated with varying amounts of potassium and the measurements were made on the range of soil/clay properties before and after treatments. The results show that applied potassium can cause dispersion of soil but to a lesser extent than sodium. Potassium cations also could increase soil hydraulic conductivity (HC) to some extent when applied to a soil with high sodium content by substituting the Na+ on exchange sites. Potassium could be fixed by clay minerals, changing their composition, decreasing cation exchange capacity and increasing mineral potassium content. This increase was confirmed by the decomposition of XRD diagrams and chemical analysis, consistently showing the increases in amount of mica/illite clay minerals in soils treated with potassium rich solutions. The dynamic of “illitisation” can be monitored by XRD analysis both qualitatively and quantitatively. X-ray computed tomography (CT) scanning of the soil columns has allowed visualization and quantification of the changes in pore system occurred due to the application of potassium.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restrict4ed access to Published version, in accordance with the copyright policy of the publisher.
Faculty / Department / School: Current - Institute for Agriculture and the Environment
Date Deposited: 11 Oct 2018 04:26
Last Modified: 12 Oct 2018 03:00
Uncontrolled Keywords: soil aggregate stability; hydraulic conductivity; clay
Fields of Research : 05 Environmental Sciences > 0503 Soil Sciences > 050304 Soil Chemistry (excl. Carbon Sequestration Science)
05 Environmental Sciences > 0503 Soil Sciences > 050305 Soil Physics
Socio-Economic Objective: D Environment > 96 Environment > 9614 Soils > 961499 Soils not elsewhere classified
Identification Number or DOI: 10.1016/j.still.2018.04.016
URI: http://eprints.usq.edu.au/id/eprint/34765

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