Impacts of sodic soil amelioration on deep drainage

Reading, Lucy, Lockington, David A., Bristow, Keith L. and Baumgartl, Thomas (2010). Impacts of sodic soil amelioration on deep drainage. In: Robert Gilkes and Nattaporn Prakongkep, 19th World Congress of Soil Science 2010. 19th World Congress of Soil Science, Brisbane, Australia, (772-775). 1-6 August 2010.

Author Reading, Lucy
Lockington, David A.
Bristow, Keith L.
Baumgartl, Thomas
Title of paper Impacts of sodic soil amelioration on deep drainage
Conference name 19th World Congress of Soil Science
Conference location Brisbane, Australia
Conference dates 1-6 August 2010
Proceedings title 19th World Congress of Soil Science 2010
Place of Publication Warragul, VIC, Australia
Publisher Australian Society of Soil Science Incorporated
Publication Year 2010
Sub-type Fully published paper
ISBN 9781618391025
Editor Robert Gilkes
Nattaporn Prakongkep
Volume 2
Start page 772
End page 775
Total pages 4
Language eng
Abstract/Summary Groundwater tables are rising beneath irrigated fields in some areas of the Lower Burdekin in North Queensland, Australia. The soils where this occurs are predominantly sodic clay soils with low hydraulic conductivities. Many of these soils have been treated by applying gypsum or by increasing the salinity of irrigation water by mixing saline groundwater with fresh river water. While the purpose of these treatments is to increase infiltration into the surface soils and improve productivity of the root zone, it is thought that the treatments may have altered the soil hydraulic properties well below the root zone leading to increased groundwater recharge and rising water tables. In this paper we discuss the use of column experiments and HYDRUS modelling, with major ion reaction and transport and soil water chemistry-dependent hydraulic conductivity, to assess the likely depth, magnitude and timing of the impacts of surface soil amelioration on soil hydraulic properties below the root zone and hence groundwater recharge. In the experiments, columns of sodic clays from the Lower Burdekin were leached for extended periods of time with either gypsum solutions or mixed cation salt solutions and changes in hydraulic conductivity were measured. Leaching with a gypsum solution for an extended time period, until the flow rate stabilised, resulted in an approximately twenty fold increase in the hydraulic conductivity when compared with a low salinity, mixed cation solution. HYDRUS modelling was used to highlight the role of those factors which might influence the impacts of soil treatment, particularly at depth, including the large amounts of rain during the relatively short wet season and the presence of thick low permeability clay layers.
Keyword Sodic soils
Amelioration
Gypsum
Deep drainage
Q-Index Code E1
Q-Index Status Provisional Code
Institutional Status UQ

 
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Created: Thu, 11 Apr 2013, 11:10:28 EST by Mrs Lucy Pamela Reading on behalf of School of Civil Engineering