What you are looking at here is salt. European style farming is putting our country out of wack. Here's the story behind salinity.
"Ground water recharge is the amount of water being added to the ground water. If this is higher than discharge, which is the amount of water lost from the ground water, then the water table rises. As it does, the water dissolves salt held in the soil profile, and the salt becomes more and more concentrated as the water moves upwards. If the salty water keeps rising, it eventually reaches the surface and subsurface layers of the soil. The water evaporates, leaving the salt behind."
There are two sorts of dry land salinity ... one caused by irrigation (adding too much water), the other caused by excess tree clearing (not enough to use the ground water up).
Around the Murray tonnes and tonnes or salt are leaching into the the river every day. A recent Basin Salinity Management Strategy is keeping 17,500 tonnes of salt from entering the Murray annually which is a very good thing. A byproduct of the process is pink salt a naturally pink coloured salt desirable to gourmets .