Towards an economic decision support system for amelioration of soil constraints in the Northern Grains Region

The aim of this review was to identify knowledge gaps in Decision Support Systems (DSSs) for assessing the economics of adopting soil constraints amelioration options. To achieve the aim, we considered available DSSs developed by research and development corporations (RDCs), primary sectors and those in the commercial domain. Literature review was also conducted involving peer-reviewed articles and reports to consolidate our findings. We identified 12 DSSs developed for Australia and New Zealand soils fully or partly aiming to help farmers manage their soil-related production constraints. The literature has been reviewed in light of the project objectives to identify proven techniques, database, and economic models where possible. There are many works aiming to scientifically (using physical or empirical models) ameliorate soil constraints but there is limited economic evaluation of soil amelioration projects. In addition to the literature review, a focus group review conducted in May 2018 has also identified a number of issues in regards to farmer awareness of the problem and their ability to formulate a response (Cameron, 2018). This project is also investigating what is available to help growers to make the investment decisions in line with the recommendation from the focus group report. A summary of the knowledge gaps and challenges, especially related to development of DSSs on economics of soil constraints amelioration have been presented below.  Most DSSs for managing soil-constraints do not include economic assessment. Currently, there is no framework or DSS for growers to analyse the economic impact of the whole of farm soil constraints amelioration in the Northern region. If present for outside the Northern region, economic analyses are confined to the calculation of income from the crop grown during the amelioration process. There is no clear path for farmers or farm advisors for them to analyse: o Whether or not to invest in amelioration options; o The long-term return on investment in amelioration/s; or o The risks involved in amelioration/s.  There is limited available experimental data related to crop yield penalties due to soil constraints. An economic component for a DSS will require datasets covering yield penalties of different soil constraints and the effectiveness of amelioration options specific to the sub-regions to offset crop yield penalties. Most particularly, the present review has not identified any data about crop yield penalties due to soil constraints in mixed crop-livestock systems of the Northern region.  There is a lack of data to quantify the combined effect of multiple soil constraints on yield: It is essential to quantify the combined effect of multiple soil constraints on yield penalty. There is no data for characterising the interactive effect of multiple constraints but modelling will provide some insight for the approximations to be included in a new DSS. The capabilities of biophysical modelling for simulation of the cropping systems with soil constraints will be evaluated and modified if required (and possible). APSIM has been used for modelling cropping systems with soil constraints, but with extensive parametrisations and including expert opinions for tunings.  There is a lack of shared scientific communications behind the reviewed DSSs. This project should consider how the scientific aspects of the research can be translated into economic terms.