When the Thatcher Government cut funding to agricultural research in the UK in 1984, English-born soil researcher Dr Paul Blackwell chose Australian soils as his next venture.

Unearthing our soils for almost 30 years now, the ex-Department of Agriculture and Food Geraldton’s soil guru is highly regarded amongst growers and researchers in the northern Agricultural region and the State.

Seeing science and knowledge take effect on farm is what agricultural research is all about and, for Paul, improving farm soils, grain yield, quality and whole farm profitability are the most rewarding parts of his job. But he says that even this is often eclipsed by the hospitality offered by innovative farming families who have bravely welcomed him on their farms over the years!

From the UK to WA soil

Originally from Grimsby, a UK fishing and industry town, Paul did his PhD on soil compaction at the Scottish Institute of Agricultural Engineering then moved to the Agricultural Research Council’s Letcombe Laboratory near Wantage in England, an agricultural research unit which specialised in plant and soil function and management. He helped study water-logging and compaction effects on wheat growth and production at Letcombe, mainly using field experiments and lysimeter units.

When the Thatcher Government cut funding to research in the UK and planned to close the labs, Paul sought work in Australia (1984).

He spent five years with the CSIRO division of soils in Canberra, studying macroporosity of irrigated clay  and hard setting,  which he said was a great introduction to Australian agriculture, research expertise and soils.

‘I got a very strong grounding in Australian soils science but there were no future prospects with them [CSIRO] so I left for a permanent job that came up at DAFWA Geraldton in 1989.

‘It’s been brilliant; the organisation is more practical and ‘down to earth’ than Canberra and growers are so receptive to new ideas over here. I got a few things wrong too; inevitably, it was a steep learning curve!

‘To see the knowledge working and to be making a difference to the industry is very rewarding. We, often in collaboration with other organisations like WANTFA, have helped growers adopt more profitable management strategies and improve their soils.’

Paul said the general consensus on non-wetting soils in the early 1990s was that these could not be fixed. At this point in time, however, with GRDC funds, some progress in the whole state was made with claying, furrow sowing and banded surfactants which changed some grower’s minds and helped improve the management of non-wetting soils.

He said no-till furrow sowing can be a very cost effective way of managing non-wetting soils but there was a fine line between its success and failure depending on the design and use of the points, press wheels and boots and accuracy of the seeder bar.

‘The consequences of the wrong combinations for no-till furrow sowing can be unexpectedly damaging,’ Paul said. ‘Many knife-points  place the non-wetting soil right in the seed zone.’

This came to light in experiments into shallow moisture delving at seeding  (2001)and helped to clarify why no-till furrow sowing with knife-points in dry non-wetting sand could be so poor. The recent (2011 onwards) GRDC-funded project led by Steve Davies in collaboration with Margaret Roper and Phil Ward of CSIRO, has looked into this issue further. Improved no-till furrow sowing offers  many cost-effective strategies to manage and even employ non-wetting to help farm profitability and financing of more expensive longer term solutions.

Paul got involved in improved seeding systems for better compaction protection  in  a Controlled Traffic project for sandplain, started in 1997 on Tony Critch’s farm near Mullewa with GRDC support and DAFWA resources.

‘We had the use of a whole paddock (400ha) and the farm sowed with a 50 foot seeder bar, after deep ripping the whole paddock and compared this to a CTF system with a 30’ research bar after lifting two of the tynes on the 30’ deep ripper to form the permanent tramlines.’ Paul explained.

In the first year the CTF system had a 7% increase in wheat yield, in the second year a 10% increase in lupin yield and in the third year another 13% increase in wheat production, all compared to the uncontrolled traffic after seeding with the farm bar. Following this, the canola yielded 11% higher in 2000 and they were getting less screenings with wheat and more oil with canola, signifying that CTF wasn’t just improving yields but was improving grain quality as well, as well as making it easier to drive around during all the cropping operations.

From 2005 to 2007 Paul and others were involved in a National Landcare-funded project on  how downhill CTF could potentially reduce water erosion problems.  They also tried using very wide rows of wheat to reduce drought stress on shallow soils, which produced some good data—however grass weeds often prove to be a big issue with very wide cereal rows.

In 2006 Paul found himself conducting one of the most effective biochar trials in Australia. It was using only 1t/ha of banded oil mallee biochar (low grade) which enabled them to use half as much fertiliser for the same yield outcome (2005, on shallow soils at Pindar).

Paul presented the findings in 2007 at the first International Agrichar Conference in collaboration with the Oil Mallee Group and, subsequently, overseas funds came through to further investigate the use of biochar as a rich fertiliser; a copy of “Terra Pretta”. He was then involved in a national team investigating biochar made from wheat chaff and chicken manure with GRDC funds.

In 2010 biochar was deprioritised in DAFWA grains research so Paul turned down a voluntary redundancy and continued to work on management of water repellence.

Following that Paul contributed a DAFWA contract to help a CTF project run by the Northern Agricultural Catchment Council, with help from the Federal Government’s Caring For Our Country grants. Bindi Isbister of North Stirlings Pallinup Natural Resources, along with Paul and other DAFWA colleagues among others, put together a new CTF technical manual released in 2013. That new activity in CTF helped encourage GRDC to fund new R&D into soil constraints and the beginning of a wide range of projects on subsoil and topsoil constraints to WA grain farming.

From 2014 to 2016 Paul helped manage a GRDC & DAFWA funded project on better soil compaction management, including CTF and deep ripping. Breakthroughs came in the clear identification of the need for deeper (>350mm) deep ripping on many soils and the possible benefits of ‘topsoil slotting’ to help get beneficial organic matter and top-dressings such as lime, gypsum or manures into the decompacted subsoils. There were also developments of new tools for CTF, such as “CTF Calculator (http://www.ctfcalculator.org/) by Bindi Isbister and James Hagan.

After Paul’s retirement in January 2017, Paul was pleased the project could be continued under the management of Wayne Parker of the DAFWA Geraldton office.


Where to from here with WA’s soils?

Since the no-till revolution more than two decades ago, there have been numerous efforts to continue to improve the productivity of cropping in WA.  We have seen machinery get bigger, guidance more accurate and chemicals more acute but soils are becoming compact and still degrading. Could controlled traffic be the next big thing? If not, what is?

‘As farms are getting bigger and large machinery is increasingly causing soil compaction problems, CTF (often with soil amelioration) is the right next step to improving soils, productivity, profitability and resilience in challenging dry seasons,’ Paul said.

But unlike the relatively simple no-till conversion, going from conventional machinery to CTF can seem harder than it’s worth.

‘No-till farming was mainly about changing your points and changing your herbicide use and you’re there. But with controlled traffic there is a lot more work—you need to change your widths of your machinery, change your wheel widths, and improve your soils. There’s much more involved, but it can be done progressively,’ Paul said.

‘The biggest barrier initially was autosteer and majority of croppers have that now, so transition is  easier than  thought fifteen years ago.’

Paul considers that knowledge and better understanding of how CTF can help improve fertiliser use efficiency is the next challenge in CTF research in WA.

Non-wetting soils is an increasing issue in WA, and other than regular rain, Paul said the best investment would be to improve seeding gear and add new designs of surfactants which he has often found to further boost yields from dry seeding.

‘You will get more total return on improved seeding method, applied to the whole program, than if you  only invest in amelioration such as claying, spading or ploughing on part of the program. This is because the cost of changing your points and press wheels and the cost of surfactants is up to about $10/ha, which will give you a better return on investment than something substantial but is about 10 times as costly, he noted.

Thus it often pays to have a mixture of technology change on the whole farm, so that improved no-till furrow sowing can help improve farm profitability and provide some investment in more expensive improvements such as claying, spading or mould boarding, which can have long-term benefits over progressively more of the farm, where it is the most effective. A paper led by Steve Davies emphasised this at the Crop Updates previously.

There is still a lot of room for improvement of cropping profitability and resilience in WA, especially with major challenges from heat stress in the northern grain regions. Paul advocates CTF, topsoil slotting- especially on sodic subsoils, saline Morrell soils and heavy yellow sands, improved no-till furrow sowing and perhaps biochar for some soil types, when they fit well into the farm growing environment, soil types and whole farm finances.

‘The ever-changing potential improving technologies are fascinating, like the possibilities of robotisation,’ Paul said.

‘CTF was developed because our machinery is getting bigger and heavier  to become more efficient, however what if the technology was smaller, lighter and faster, driven by robotics controlling multiple, domestic car-sized units?’

‘The possibilities are impressive—you may no longer have compaction issues and the need for permanent tramlines, assuming suitable soil improvements have already been made.’

It may sound far-fetched in 2017, but Paul said in 1997 very few people saw autosteer coming, and five years later it was a normal fit into new tractors.

‘That’s the interesting thing about technology; it can come around quickly and catch us all by surprise.

CTF back on the radar

CTF was off the radar in WA for some time but it’s coming back strong and could potentially be better and easier than ever, according to Paul.

‘Many farmers in WA have unknowingly forgone profit they could have had if we had of kept the ball rolling with CTF and encouraged more adoption earlier on,’ Paul said.

However, not many machinery businesses are interested in providing a consultancy service to optimise conversion to CTF. Such private enterprise should be a viable business and thus be a lobby for more business, as is happening with VRT. Curiously enough, adoption of CTF will often be more profitable than VRT!

However CTF adoption may not be an easy fix as each farm is unique and a one-on-one with people who can assist with adoption may be critical to its success.


Picture: Soil core sectioning, testing non-wetting at different depths.



Paul would like to thank the following people, as some of many who had helped:

Graham Malcolm and Lindsay Chapel of Morawa who introduced me rapidly to WA farming.

The late Fred Rodgers of Gillingarra and Robin Randal who showed me some practical on-farm furrow sowing for non-wetting sands.

Bill Crabtree of Jerramungup  who introduced me to the south coast.

Glen Riethmuller, Ron Jarvis and Kevin Bligh who introduced me to tillage and the lack of it.

The Vlahovs of Yuna who showed some early traffic control effects in their blue lupin pastures.

The Critch Family of Tenindawa and the Obst Family of Strawberry who bravely hosted the CTF trials on their farm for four years.

Rohan Ford of Balla who took up CTF to try and get me off the farm (it did not work!).

GRDC and Commonwealth funding panels as well as Department support for various and varied activities.

Stephen Joseph and Syd Shea who tempted me into charcoal research.

Grant Morrow and Dave Nicholson for heaps of field work in the 90s.

Tony Proffit, Dave Hall, Dan Carter, Derk Bakker, Stewart Edgecombe, Wayne Parker, Bindi Webb/Isbister, Steve Davies Rob Grima and Chad Reynolds for working with us more recently and usually tolerating my crummy jokes.

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