Can subsoil amelioration improve the productivity of grain production in medium-high rainfall environments?

Roger Armstrong1, Peter Sale2, Ehsan Tavakkoli3, Nigel Wilhelm4, David Davenport5, Geoff Dean6, Bill Malcolm7, Jon Midwood8, Pichu Rengsamy9, Cam Grant10, Garry O’Leary11 and Jack Desboilles12

1 Agriculture Victoria Research, DEDJTR, 110 Natimuk Rd, Horsham, Victoria, 3400, roger.armstrong@ecodev.vic/

2 La Trobe University, AgriBio Centre, Ring Rd, Bundoora, Victoria, 3083

3 NSW DPI, PMB, Pine Gully Road, Wagga Wagga NSW 2650

4 SARDI, Building 11A Hartley Grove, Waite Research Precinct Urrbrae, South Australia, 5064

5 PIRSA Rural Solutions, Lincoln Marine Science Centre, Port Lincoln, South Australia, 5606

6 Tasmanian Institute of Agriculture, Private Bag 1375, Prospect, Tasmania, 7250.

7 The University of Melbourne, Dept. of Agriculture and Food Systems Royal Parade, Parkville Victoria, 3010

8 Southern Farming Systems, 23 High St., Inverleigh, Victoria, 3321

9 The University of Adelaide, Waite Campus, Urrbrae, South Australia, 5064.

10 The University of Adelaide, PMB 1, Glen Osmond, South Australia, 5064

11 Agriculture Victoria Research, DEDJTR, 110 Natimuk Road, Horsham, Victoria,

12 University of South Australia, Mawson Lakes Campus, Mawson Lakes, South Australia, 5095


The water limited yield of many grain crops growing on poorly structured subsoils in the medium-high rainfall zone of south eastern Australia falls far short of the full potential. Previous research has demonstrated that applying large quantities (> 10 t/ha) of organic matter, commonly referred to as subsoil manuring, can markedly improve grain yields for at least several years. A number of issues has limited the commercial implementation of this technology on-farm, including unpredictable yield responses, high upfront costs, the availability of suitable organic matter sources and the lack of commercially available machinery to apply the organic matter. Critically, the exact mechanisms underpinning the yield response and how this varies with the form and rate of organic matter used, soil type and seasonal conditions is unclear. We argue however that if these issues can be resolved, then there is the potential to significantly improve both the productivity and profitability of grain production in these cropping systems.


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.

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David Marland Photography Southern Farming Systems Agriculture Victoria

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