Understanding the amelioration processes of the subsoil application of amendments

Iman Tahmasbian1 2, Zhe H. Weng1, Yunying Fang3, Graeme Poile1, Albert Oates1, Shihab Uddin1, Binbin Xu1, Graeme Sandral1, Roger Armstrong4, Ehsan Tavakkoli1 2*

1New South Wales Department of Primary Industries, Wagga Wagga Agricultural Institute, Wagga Wagga, NSW, 2650,
2Graham Centre for Agricultural Innovation, Charles Sturt University, Wagga Wagga, NSW,  2650,
3NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle NSW, 2568, Australia,
4Agriculture Victoria Research, Department of Jobs, Precincts and Regions, Horsham, VIC, 3400

* Corresponding author: ehsan.tavakkoli@dpi.nsw.gov.au


A series of field and incubation experiments were conducted to address the amelioration process of physicochemical constraints of alkaline sodic dispersive subsoils. A range of organic and inorganic amendments were applied in the top and subsoils with the plots sown to barley and wheat in 2017 and 2018, respectively. The initial results indicated that deep application of combined organic and inorganic amendments resulted in significantly improved soil physicochemical properties and increased yield in the two consecutive years. The deep application of gypsum and organic amendments reduced the soil pH and exchangeable sodium percentage (ESP) and improved soil aggregate stability, addressing both chemical and physical constraints. The results indicated that amendments and strategies with different mode of actions are required for improving soils with multiple physicochemical constraints.


The Australian Society of Agronomy is the professional body for agronomists in Australia. It has approximately 500 active members drawn from government, universities, research organisations and the private sector.

Photo Credits

David Marland Photography david_marland@hotmail.com Graham Centre for Agricultural Innovation, Charles Sturt University

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