Deep sandy soils, as found regularly in the Mallee region of South Australia and Victoria, and are often overlooked as ‘gutless’ sands. However it is apparent upon further investigation that there is a lot more going on in many of these soils. Soils should never be underestimated.
Without digging into these soils it is often a perception that the roots and water just keep moving down almost indefinitely into the profile, however it is quite typical to see roots not exploring depths much greater than 400mm in what appears to be a relatively uniform soil.
It is not until further investigation is carried out to look at pH, EC, sodium, boron and clay content that reasons behind growth limitations become apparent.
As seen in another story in this weeks Soil Expedition, pH can vary quite rapidly leading to alkaline subsoils that are high in sodium, boron and calcium is effectively tied up as calcium carbonate. All of these factors contribute to poorer plant performance, however productive capacity can be managed effectively when issues are identified from precise assessment of pit profiles.