The maps above show the relative levels of modelled upper (0 to 0.2 metres) soil moisture and lower (0.2 to 1.5 metres) soil moisture at the end of January 2014. These maps show soil moisture estimates relative to the long-term average over the reference period 1961 to 1990.
The bulk of plant roots occur in the top 0.3 metres of the soil profile and soil moisture in the upper layer of the soil profile (0.2 metres) is the most appropriate indication of the availability of water, particularly for germinating plants. The lower layer soil moisture is a larger, deeper store that is slower to respond to rainfall and tends to reflect accumulated events over seasonal and longer time scales.
After assessing many soil pits around Australia over the summer it has been amazing to see the amount of subsoil moisture that is still present. When planning for the season ahead it is beneficial to dig a pit to visualise the subsoil moisture present and to see if there are any identifiable and manageable constraints to root development in the subsoil layers.
