Recently in the Goondiwindi area, cotton roots depths were tested in various fields using a capacitance probe.
It was found some crops were drawing water from 100cm, some 80cm and about 30% were only around 60cm deep late in the season.
The shallower roots depths could be caused from poor soil structure leading to a reduction in root penetration and lower water extraction. These fields with lower root depths were also showing issues with irrigation water, such as run off.
Dr Oliver Knox of from the University of New England, said there was a range of options growers could try to repair soil structure and restore rooting depth. Given the levels of soil compaction and sodicity, gypsum was an option but given the depth it might have to be dip ripped or applied yearly to achieve results over the long term with applications of organics and crop rotation.
Source: The Land – Neil Lyon