- Growers: Matthew and Rachel Hinkley
- Location: Derrinallum, Victoria
- Property size: 1745 hectares
- Annual average rainfall: 650 millimetres-plus
- Soil types: clay loam, heavy grey clays
- Soil pH: ranges from 4.7 to 6.0 (in CaCl2 from zero to 10 centimetres)
- Enterprises: cropping, trade lambs over summer
- Crops: canola, wheat, barley, clover and ryegrass hay
- CTF system: wheel tracks based on two-metre raised beds.
Such has been the rapid development of Victoria's high-rainfall cropping zone (HRZ), it is easy to forget it is little more than 20 years since the first 'winter' - or dual-purpose - wheats ushered in this cropping revolution.
Since then, a raft of new practices and technologies have evolved in the HRZ, in particular, controlled-traffic farming (CTF) and its ally, raised beds.
This backdrop largely explains the course taken by HRZ growers Matthew and Rachel Hinkley, from Derrinallum in western Victoria. For them, CTF has been the means to an end - effectively, the tool that enables them to exploit reliable rainfall to grow the highest-yielding grain crops possible.
The Hinkleys bought a "tired" sheep property in 2004 and immediately started setting up a raised-bed system, which by default incorporates controlled traffic.
"Our aim was to improve the structure of our heavy cracking clays and to eliminate waterlogging while simultaneously improving the soil's water-holding capacity," Rachel says.
This is quite a challenge with their high growing-season rainfall (400 to 500 millimetres), but Rachel says the benefits far outweigh the management demands and cost of maintaining raised beds.
The Hinkleys now crop 1745 hectares, rotating between canola, wheat and barley, with more than 90 per cent of the farm under raised beds.
With the raised beds and CTF we've seen a gradual but clear improvement in soil structure.
All raised beds are formed between two-metre wheel tracks - the harvester is 12m and the sprayer and spreader 36m. While the seeder is currently 10m, they are in the process of changing to 12m to complete the 12m/36m system.
The gutters are sown to crop to reduce weed competition and, while low-yielding compared with the uncompacted beds, at 20 per cent of the paddock, they still need to be utilised.
Water management vital
From day one, the Hinkleys focused on managing their water. All paddocks were topographically mapped to determine the best direction for water flow and the position of drains.
They bought their own earthmoving equipment for drain forming and maintenance, which is ongoing.
"Each year, earthworks are undertaken before sowing and we've had plenty of experience getting machinery out of bogs," Rachel says.
For us, controlled-traffic farming has been a tool to improve the structure of our heavy cracking clays - eliminating waterlogging while also improving the water-holding capacity.
When ground conditions are too wet, inputs are applied from the air and they've just commenced a 'zero-compaction' trial, to assess the economic viability of applying all post-sowing inputs by air.
Early farm trials in the area showed that just one tractor pass on uncompacted ground could reduce yields by 15 to 30 per cent.
Where a contractor's boom ran across crops in 2016, the harvest monitor showed a clear yield drop from 10t/ha to 7t/ha in a wheat crop.
"With the raised beds and CTF we've seen a gradual but clear improvement in soil structure," Rachel says.
"The uncompacted soils are better able to hold plant moisture and have better root development.
"Crop productivity is our priority and, of course, CTF is just one piece of the puzzle. You still have to get the crop varieties, agronomy and everything else right."
The Hinkleys' top three CTF tips are:
- While there is a perception that CTF is expensive, the transition can be gradual. Make a start and have a plan allowing for ongoing development as machinery is purchased over time.
- Think carefully about equipment purchases and compatibility. Consider trading-in existing plant if it does not suit the configuration.
- Everyone involved in the business needs to understand the importance of CTF and the need to stay on trafficked areas.
More information: Matthew and Rachel Hinkley, firstname.lastname@example.org