DAV00149 - 2016.05.07 Understanding the amelioration processes of the subsoil application of amendments in the Southern Region

Most cropping soils in the Southern Region contain one or more subsoil physicochemical constraints, such as high boron or sodicity, that can effect root growth, limit water and nutrient use by crops and decrease yield.Sub-soil manuring (application of large amounts of organic matter at depth) has displayed some potential but adoption is limited by a lack of information on economic return, logistics and suitable machinery. This investment aims to develop the knowledge, agronomic practices and review the machinery available to support the reliable adoption of subsoil manuring whilst reducing the associated financial risk and other logistical constraints currently limiting the uptake of this practice.

Specifically this project will:
(i) review current knowledge about organic matter application to soils and how they can boost crop yields (from Australia and overseas) and use this knowledge to guide future R, D and E;
(ii) continue to monitor existing field trials to assess the long term residue value of applying organic matter on grain yields and use a series of new field and controlled environment trials to develop a better understanding of the soil chemical, physical and biological properties and crop processes underpinning improvements in crop performance following the application of organic matter to subsoils. This component will also optimise combinations of organic matter source, rate and depth of incorporation needed to increase crop yields on different soil types and environments in medium and high rainfall zones of South Australia, Victoria, southern NSW and Tasmania.
(iii) undertake a scoping study of machinery design needed to apply different sources of organic matter to subsoil to guide the development of future commercial equipment and
(iv) undertake an analysis to identify the most financially attractive scenarios (soil type and environment/yield potential) for subsoil amelioration by accounting for the impact of seasonal variation, different input costs such as organic matter sources, commodity prices and the residual value of treatments based on data obtained from the field trials and simulation modelling using long-term climate records.