Knowing your soils

This event was a WMLIG initiative supported by Rice Extension and made possible with funding from the Murray LLS through the Australian Government's National Landcare Programme.

19-20th March 2018
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Sixteen people attended a soil analysis workshop in Wakool and Deniliquin in late March. This workshop was created with the initiative to help producers understand their soil and gain confidence to investigate soil constraints. Producers are familiar with the physical appearance of their topsoil, but often overlook the importance of their subsoil characteristics and capability when making management decisions.   

Sue Briggs and John Fowler from MLLS presented on the key components of the physical characteristics such as identifying soil colour, texture, structure, compaction layers and root growth.  The two sites were irrigated Lucerne stands, identified as Sodosols. They displayed a sodic layer at the top of the “B” horizon and are the common soil type of the region.
 
Sodosols are renowned for poor soil structure due the high level of sodium on the clay surface. This was demonstrated by placing a bit of the soil into a dish of water and the water turned “cloudy” or “milky”. However at both sites the Lucerne root was able to grow through that layer. 

Pauline Mele, the principal research scientist for AgriBio followed Sue’s presentation with a discussion on soil biology within farming systems. She began by stating: “Our soil biology is very resilient and remains dormant in the soil during dry periods and can even change its state to handle different oxygen levels during soil saturation.”
 
Currently, research in soil biology is still in the discovery phase. Microbial populations within our soils are the most diverse and complex of any system. There is still a lot to learn about how these microorganisms can influence agriculture, but there huge potential for their future use.
 
Pauline cautioned, “if you are considering the use of products that claim to add beneficial biology to your soil; always trial a small area over a few years to assess if it is influencing your crops. The hard thing about adding biology to a system is that you are applying a living organism, so storage can be an issue and the environment it is being added to may not be suitable for successful colonisation. At the end of the day, what are you trying to achieve with that product? Will the microbes be suitable for that purpose? Our research is only just beginning to ask these questions, so can a business be confident their microbial mix is fit for the job?.”
 
The WMLIG would like to extend thanks to Michael Shannon and Steve and Linda Fawns for hosting our soil workshops and providing soil pits for the day, as well as the North Central Catchment Management Authority for donating soil handbooks (available at the WMLIG office) for attendees.