Bleached-Orthic Tenosol - Noel Schoknecht, Federal Secretary
During the year of soils, each month we ask a soil researcher to select his or her favourite soil. Noel Schoknecht is the current Secretary of Soil Science Australia. Noel is a long serving soil surveyor in Western Australia and has Chair of the National Committee on Soil and Terrain. He is also fascinated by soil classification, so this one poses a particular problem.
If you had to choose a special Australian soil type what would it be?
When I moved from Victoria to Western Australia in 1991 I was fascinated by the extent of sand in the south-west of this state, and the number of ways we use to describe it. In our texture descriptions we have more than doubled the number of terms used nationally to describe sand to capture the small differences in clay % that made a big difference to land use. Hence, for example, a sand texture becomes a very weak clayey medium sand. Our WA nickname of being Sandgropers (a kind of grasshopper adapted to subterranean life in sand) is quite appropriate.
Our pre-occupation with sands actually gave us an advantage when we surveyed the deserts of Kuwait and Abu Dhabi!
What are the main properties of this soil type?
One of the worst kinds of sand, our so called “gutless sand” or more optimistically called “silver loam” by some, is the Pale deep sand which currently classifies as a Bleached-Orthic Tenosol.
Any of you that have discussed sands with me would know that I don’t support sands being in the “left over” Tenosol Order, and am currently working on a new Order of Australian Soils called the Arenosols (sands). But I diverge…
The main properties of this soil are that it hasn’t got many. It is basically siliceous sand with a bit of organic matter in the surface. It has low nutrient status and water holding capacity but is widespread on the coastal plains of the south-west of WA and scattered throughout the wheatbelt.
It’s not without its problems though, as it can be ferociously water-repellent, loses added nutrients to the groundwater and waterways, blows when left exposed and is generally a difficult customer to work with. When I first came to the west I was amazed that it would grow anything at all.
Why do you find this soil type particularly interesting?
I find it interesting because, with carefully management, it can be productive for horticulture and is used for vegetable production around Perth and other areas.
Where it really shines through is through the native vegetation that grows on it, with a wild abundance of beautiful flora adapted to its low phosphorus status and low water-holding characteristics. In many areas this is the most appropriate land use.
I am hoping one day I can call them Bleached Arenosols.