The objective of this project is to evaluate a range of commonly available approaches to increasing the fertility of the ‘gutless’ soils in the medium and high rainfall zone of WA. This project will apply a combination of organic amendments and physical amelioration methods that are complimentary to each other in order to determine the grain yield benefit over three years. The return on investment for each approach will be evaluated to guide growers on the most profitable approach to improving poor productivity soils.

There were no conclusive benefits or outcomes in terms of yield or grain quality from applying organic soil ameliorants in conjunction with physical soil amelioration over and above just the physical soil amelioration. Further work is required to improve our understanding of the potential impact of these organic soil ameliorants. However, it is worth noting that from the results there was no clear yield benefit from the physical amelioration of mould board ploughing which has been well established over the past decade or longer. This result potentially demonstrates the impact of the severe wind event that was experienced just after sowing the trial in year one on the overall project results.
The cost associated with applying the organic soil ameliorants can be extremely high, with the total application costs ranging from $135/ha to $1040/ha for the high rate of manure (40 t/ha). It is expected these ameliorants will last in the soil for more than one season and therefore the costs can be amortised across several seasons. Improved understanding of the length of impact of the different types of organic ameliorants in these soils is required to better understand the annual cost and to determine the benefit cost analysis of applications.