Many Australian landscapes are old, and have fragile soils. European agriculture has had a profound impact. This slide shows some figures (the first 4 dot points) from the National Land and Water Resources Audit which showed that, large as the problem of salinity looms at the moment, other problems occupy larger areas or result in greater profit foregone. Some years ago, a report showed that soil structural decline was the greatest problem in New South Wales, but nowadays, except for sodicity, it barely seems to rate a mention. The point, however, is not which problem is the greatest, but that they are linked. I shall develop this point in the rest of the talk.