20 years of soil acidity RD and E in WA – what have we learnt?

The severity and extent of soil acidity, including subsurface acidity, has been mapped across the south-west of WA and the current condition and trend are rated as poor. Growers’ understanding of their soil’s pH profile is contributing to an increase in the rate of lime applied per hectare and they intend to increase total lime use further. However, the amount will need to be substantially more than their intended 2 t/ha to achieve appropriate pH profiles. Twenty years of soil acidity research in WA has shown a large range in yield benefits to liming which varied due to severity and depth of soil acidity and the extent to which liming ameliorated the constraint. An alternative approach is needed by economists, consultants and advisors to promote lime as an essential input because in many cases much more than 2 t/ha is needed to recover the soil profile.