Category Archives: Controlled Traffic Systems

Agronomy, Controlled Traffic Systems, Drainage, Precision Agriculture, Projects, Soil, Water

Auckland Region Precision Agriculture Field Walks

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On Thursday 19 November a LandWISE field day started at 10am at NZ Fresh Cuts at Mangere, South Auckland.
Chris Butler described the adoption of a permanent bed system in their salad growing operation.

GPS use and Controlled Traffic Farming have evolved there, to the point where fuel savings of about 50% are being gained over conventional practices. A reduction in the number of cultivation operations has been made possible and this has the benefit of allowing more crops per season on this property.

The next challenge is in optimizing Nitrogen fertiliser efficiency, which will enhance their profitability dramatically.

The use of NDVI sensing will be explored as part of the LandWISE project at this site. This will be with the support of Agri Optics from Canterbury.

Lunchtime Presentations on the Advanced Farming Systems and Holding It Together projects were given by James Powrie- LandWISE and Paul Johnstone- Plant and Food Research at the Franklin Centre in Pukekohe.

In the afternoon about 20 visitors saw the AS Wilcox and Son permanent bed trial in Pukekawa. Wilcox’s are trialling controlled traffic and permanent beds in a 3 year trial in potatoes, onion and oats. They aim to gain in soil quality, efficiency and a reduction in harvest cost by reducing compaction. They also talked about their journey in adopting and now expanding the use of GPS in their cropping operation.

Thanks to Plant and Food Research, AS Wilcox and Sons and NZ Fresh Cuts.
For further information: Call James on 06 6504531 or 0272 757757, email james@landwise.org.nz or see www.landwise.org.nz for updates.

Agronomy, Controlled Traffic Systems, Drainage, Precision Agriculture, Projects, Soil, Water

Precision Ag in Vegetables – November Field Walk in Levin

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On Tuesday 24 November 2009 an Advanced Farming Systems and Holding It Together Project update was given by James Powrie- LandWISE and Paul Johnstone- Plant and Food Research. The update was held at Levin RSA following on from a HIT project team meeting.

In the afternoon this was followed by a field walk to Woodhaven Gardens where Antonia Glaria showed 15 visitors their trials in Controlled Traffic farming and Permanent beds for Fresh vegetables.

Early improvements in soil structure are encouraging as soil structure recovers with a reduction in wheel traffic and cultivation. Furrow diking was also observed and HIT project sediment traps were visited by the group with discussion on amelioration of the effects of soil loss in intensive vegetable cropping.

Furrow diking is having the effect of reducing ponding and enhancing infiltration at this farm.

Thanks to Plant and Food Research and Woodhaven Gardens.
For further information: Call James on 06 6504531 or 0272 757757, email james@landwise.org.nz or see www.landwise.org.nz for updates.

Agronomy, Controlled Traffic Systems, Precision Agriculture, Projects

LandWISE Gisborne Field Walk

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On 1 December about 20 visitors walked the paddocks at Opou Station, Manutuke, near Gisborne.

This field walk was courtesy of David Clark and gave local farmers and industry people a chance to view his Precision Agriculture program in maize. 8 seasons of controlled traffic have benefited soil structure, biology and profitability at this site, along with a 50% reduction in fuel use. Fuel savings are due to the heavy cultivation operations becoming redundant after wheel traffic was isolated to permanent tracks using GPS.

David and Stuart Briant spoke about their adoption of GPS to control traffic and reduce overlap in their mixed cropping and specialized seed growing operation. They have passed the teething stage and are seeing benefits in efficiency and operator comfort.

Thanks to Clark Farming and F&D Briant for their support of LandWISE and this event.
For further information: Call James on 06 6504531 or 0272 757757, email james@landwise.org.nz or see www.landwise.org.nz for updates.

Agronomy, Controlled Traffic Systems, Irrigation, Precision Agriculture, Projects, Water

Foundation for Arable Research Combinable Crops

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On 3 December 2009 FAR held their Combinable Crops Field Day at their arable trial site in Chertsey in Canterbury.
420 attended and saw presentations on technology, cropping, water and Precision Ag.
Speakers included Carolyn Hedley from Landcare Research on Precision Irrigation, Ian Yule from NZ Centre for Precision Ag, along with FAR presenters, Andrew Curtis from Irrigation NZ, researchers and farmers.

James Powrie and Dan Bloomer, spoke on the Advanced Farming Systems project and strip tillage.
Jim Wilson, Precision Ag specialist and arable farmer from UK was the keynote speaker, on crop sensing, zonal management and variable rate and his presentation is here as a separate posting.

Thanks to FAR for the high quality of this event and for assembling an audience who are showing more and more interest in Precision Ag.
For further information: Call James on 06 6504531 or 0272 757757, email james@landwise.org.nz or see www.landwise.org.nz for updates.

Agronomy, Controlled Traffic Systems, Drainage, Precision Agriculture, Projects, Water

FAR and LandWISE Precision Ag field day at Lawson’s Organic Farms in Hastings

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On 8 December FAR and LandWISE co-hosted a Precision Agriculture and Advanced Farming Systems session at the Centre for Land and Water. Jim Wilson from Soil Essentials in the UK, gave a presentation on crop sensors and variable rate management to a group of 28 farmers and industry representatives.
Case IH sponsored lunch for the group at the Centre for Land and Water.

After lunch the group reconvened at Lawson’s Organic Farms to view Scott Lawson’s high tech organic operation in Ngatarawa road. Scott is using GPS to guide his cultivation in a seasonal controlled traffic operation in fresh and process vegetables.

Thanks to CASE IH, FAR for support of this event and True Earth Organics for hosting the field walk.

For further information: Call James on 06 6504531 or 0272 757757, email james@landwise.org.nz or see www.landwise.org.nz for updates.

Controlled Traffic Systems, Drainage

Guest Post: John McPhee, on Maintaining Wheel Tracks for CTF #1

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If you are into CTF, you will know your paddock has two distinctly different soil conditions – loose and friable for growing crops, and hard and compacted for driving on. You will also realise that each area requires different management. A successful CTF system is more than just getting the wheels in the right place.

To a large extent, your cropping soil will look after itself once you keep the wheels off it. However, managing wheel tracks is very important and introduces some civil engineering to your farming enterprise.

The ideal CTF wheel track is hard, dry and wide enough to support wheels without sliding off. In vegetable production, wheel tracks tend to be narrow to maximize the crop area and are often wet, either from rainfall or irrigation. A wet wheel track may be greasy and hard to stay on, but an underwater wheel track will have lost a lot of its strength. This can lead to deep ruts from essential passes, such as from unavoidable harvest traffic.

So what to do about it, and do I have all the answers? No, I don’t have all the answers – but here are some ideas, some based on experience, others as yet untried.

First and foremost; correct paddock layout and effective surface drainage are essential to good wheel track performance. Some slope (and farming above sea level!) is a good start. Wheel tracks should run up and down slope for positive drainage. In undulating topography, there are probably places where you travel across slope to some degree, but positive drainage is the key. Strategic drainage might be necessary if there are low spots in the paddock.  Upslope diversion drains to prevent run-on, and down slope drains to collect run-off, are key elements. These should take water away as fast as possible, and may be broad-based and grassed so they can be driven over. They may be incorporated into paddock headlands.

Flat (or very low slope) paddocks present particular challenges. Laser grading may be an option. Consider laser grading just the base of the wheel track. The bed height may vary a little, so you will have to judge what is acceptable.
Will this solve all your problems? Probably not. Track erosion is one potential issue, depending on slope, although with improved infiltration in the bed, there should be a lot less water running down the tracks.

Daily harvest pressures for fresh produce are a challenge. You don’t always have the freedom to wait for tracks to dry, but at least if they are drained, they will regain their strength faster. Greasy tracks test the system – steerage discs on tractors and other equipment may help.

Despite your best efforts, there will be times when it all turns to custard. Maintenance of wheel tracks will be part of your CTF work program. After all, they are roads, and roads need maintenance. And it’s a fair bet you will spend less time maintaining them, than you would otherwise spend cultivating.

Pictures: Trafficability impacts on a heavy clay soil after rain (lots of it – 150 mm in 2 days).

This is a conventional tillage area 2 days after rain

Conventional post rain red

And here, a well drained CTF wheel track 2 days after rain

CTF post rain red

John McPhee

John is a Controlled Traffic Farming researcher at the Tasmanian Institute of Agricultural Research and the Department of Primary Industries.

Controlled Traffic Systems, Drainage, Precision Agriculture, Projects

LandWISE Events November-December 2009

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LandWISE, FAR and the Sustainable Farming Fund, invite you to attend the following events:

Monday 16 November 2009

FAR and LandWISE Precision Agriculture and Advanced Farming Systems Field Day Canterbury

(2.00pm – 4.30pm)

Location: Courtesy John Evans, Tregynon, 1723 Mainwarings Road, RD11, Dorie near Rakaia, Canterbury.

Sign posted from Dorie Hall, cnr Mainwarings Rd and McCrory’s Rd

Discussion:

Carrot seed crop establishment trial – differences to date

Mechanical Weeding – demo

Update on NI Advanced Farming Systems farmers – What other NZ farmers are up to with Precision Agriculture

Thursday 19 November

Field Walk NZ Fresh Cuts – Chris Butler

Permanent beds for Fresh vegetables – GPS and controlled traffic farming

(10am – 12pm)

Location: Courtesy NZ Freshcuts, Driveway on left at end of Prices Road, Mangere, South Auckland.

Discussion: GPS protocols

Update on ‘Advanced Farming Systems’ and ‘Holding it Together’ projects

(1.00-2.30pm)

Location: The Franklin Centre, Massey St. Pukekohe.

Discussion: LandWISE GPS protocols

Field Walk: Controlled traffic for potatoes and onions A S Wilcox – Simon Wilcox

(3.00pm – 4.30pm)

Location: Courtesy AS Wilcox, 567 Mercer Ferry Road (on right after Hunter rd if coming from Pukekohe) Pukekawa, South Auckland

Tuesday 24 November 2009

Update on ‘Advanced Farming Systems’ and ‘Holding it Together’ projects

(1.00pm-2.00pm)

Location:   Levin RSA 32 Bristol St. Levin.

Discussion:   LandWISE GPS protocols.

Field Walk on Controlled Traffic farming and Permanent beds for Fresh vegetables

(Furrow diking for improved infiltration and soil protection will also be viewed)

(2.30pm-4.30pm)

Location: Courtesy John Clark, Woodhaven Gardens, Joblins Rd, Levin.

Discussion:   Controlled Traffic farming, Soil conditions, Furrow diking.

Tuesday 1 December 2009

FieldWalk Precision Agriculture, Opou Station – Clark Farming/ F&D Briant

Update: ‘Advanced Farming Systems’ and ‘Holding it Together’ projects

(10.00am-12.00pm)

Location: 190 Papatu Rd Manutuke, Gisborne

Discussion: CTF maize and squash, GPS adoption, LandWISE GPS protocols

Thursday 3 December 2009

FAR Combinable Crops Field Day 2009

(1.30pm to 6.30pm)

Location: FAR Arable Research Site, 2km north of Chertsey, SH1

Key note speaker: Jim Wilson, Precision Ag specialist and arable farmer from UK.

Advanced Farming Systems project update, Strip Tillage presentation.

Friday 4 December 2009

FAR Precision Agriculture and Advanced Farming Systems Field Day

(10.30am – 12.30pm)

Location: Courtesy Craige Mackenzie, Greenvale Pastures, 337 Reynolds Road, Methven.

Discussion:

Nick Poole – MAF/FAR crop sensing project           

Jim Wilson – PA and Crop sensors

General exploration of what Craige has been doing with PA.

Tuesday 8 December 2009

FAR and LandWISE Precision Agriculture and Advanced Farming Systems Field Day

Presentation by Jim Wilson of Soil essentials in UK, on crop sensing and PA at Green Shed

(12.15pm-1.00pm )

Location: Green Shed, Centre for Land and Water, 21 Ruahapia Rd, Hastings

Field walk and discussion on Precision agriculture at Scott Lawson’s organic farm.

(2.00pm)                             

Location: Courtesy Scott Lawson, Lawson’s Organic Farm, 302 Ngatarawa Rd, Hastings

For further information:

Call James on 06 6504531 or 0272 757757 or email james@landwise.org.nz

Controlled Traffic Systems, Precision Agriculture, Projects, Soil

Stop jumping on the bed! ???

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CTF- Taking the tractor off your beds and onto permanent tracks

As featured in ‘Grower’ October 2009

Controlled Traffic Farming is a simple way to dramatically reduce input costs (time, fuel & machinery) – while sustainably increasing crop yields – towards increased farm profit.

With appropriate agronomy and management CTF is being used in NZ, Australia, South Africa, US and Europe.  Farmers use CTF to maximise the potential of both the cropped and wheeled areas for their specific purposes.   The tracked areas in the paddock become valuable in saving fuel and for bearing traffic in wet conditions, meaning operations can continue or resume sooner after rain.

CTF simply involves confining all field vehicles to the least possible area of permanent traffic lanes to avoid the soil damage and costs associated with conventional cropping.

This makes sense.  Just like us, soils can’t do their work as well if they have been run over by a tractor.  I mentioned this at a LandWISE presentation. A woman in the audience told me about her tractor ‘bite’ and that once was enough for her! 

We have been told all our lives not to walk or barrow on the beds in our vege gardens.  Now RTK GPS technology gives us the ability to stay off the beds in our crops too. 

Dan Bloomer and I, together with a few other Kiwi’s, attended the Controlled Traffic conference and Precision Agriculture Symposium in Australia in September.   Australian adoption of Precision Agriculture and GPS guidance is growing rapidly.  It was a good place to learn what our neighbours are up to.  Their soils have suffered decades of wheel damage.  The Australians have learned that compacted soils shed more water, making the impact of floods and droughts worse.  So they are becoming big fans of CTF. 

We learnt that some 4000 RTK GPS units are in use for tractor guidance over there and nearly 11% of cropping in Australia is under controlled traffic.   Some farmers in Australia have cut their machinery costs by as much as 75% while their crop yields have risen.  With water such a limiting factor it was exciting to hear that CTF farmers were having their crops mature where their neighbours were not able to harvest in drought.  Adoption in this environment is proving rapid.  The SPAA website is worth a look: www.spaa.com.au

Does this apply equally here in New Zealand?  LandWISE project farmers across the country are also working with controlled traffic farming and are teaming up to share information and methods in vegetable production.

Woodhaven Gardens in Horowhenua grow fresh vegetables, supplying markets year round.  John Clarke was very keen to explore the advantages of controlled traffic.  He wants the improved soil structure and increased accessibility to the crop offered by firmer permanent wheel tracks.  And he is keen on less flooding because of better infiltration of water into the soil.  Reduced fuel consumption is a bonus of a CTF system.  

Antonia Glaria is the Agronomist and Production Manager at Woodhaven. She is responsible for trialling the conversion to a controlled traffic system.  “We are happy with how the soil is looking after the changes we have made to the system” says Antonia.

Existing equipment fits with the change and less field operations are needed, because much of the soil compaction has gone.  The tractor is mounted with a Trimble RTK GPS for bed forming and planting.  John plans to add another GPS system in the near future to extend their use of CTF and get the gains of GPS in other operations.

Antonia is sharing her experiences from the changes with Chris Butler at NZ Fresh Cuts. Chris is also a LandWISE project farmer.  He has been using controlled traffic for salad production in Auckland and in the Waikato. The system he has developed is similar to the Controlled Traffic Farming at Woodhaven.

If you would like to learn more about controlled traffic, you can visit the LandWISE website, there is plenty of information, as well as pictures and links to video in the resources section at: www.landwise.org.nz

Agronomy, Controlled Traffic Systems, Drainage, Precision Agriculture, Soil, Uncategorized, Water

Australian Controlled Traffic Farming Association Conference – September 2009

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Hi-Tech – Low Emissions Cropping – Economical – Energy Efficient – Environmentally Sound

Dan and James from LandWISE attended the Australian Controlled Traffic Farming Association (ACTFA) conference in Canberra.

Australian adoption of GPS

It was estimated that 4000 RTK GPS units are in operation on vegetable and arable farms in Australia.  CTF adoption is estimated at 11% of cropping farmers and is climbing. Growing local networks of CTF farmers are apparent through the presentations and workshops and in talking to farmers we met. 

Aussie Drought

CTF as a solution to many challenges in soil, water and staying in business, has acceptance among the farmers with whom we spoke.

Farmers with experience of CTF spoke in terms of gains in Water Use Efficiency and drought tolerance of their operations.  They spoke of neighbours, unable to harvest droughted crops, asserting that they were getting less rain than CTF farmers.    

One agricultural contractor only has customers that operate CTF systems.  This is a deliberate business strategy; in dry years his customers have harvestable crops and he wants the consistent work.

Dire issues with water shortages sharpen the interest of farmers in Precision Agriculture.  The large holdings and low per hectare yields reported by Australian grain farmers means small per hectare savings are significant.  Margins are tight and grain prices under downward pressure.  Any gains offered by technology are being explored and exploited. 

Water use efficiency (in kg/mm rainfall/ha.) is a common measure of gains from Controlled Traffic Farming in Australia.  Improved infiltration and soil moisture storage are important reasons to convert to CTF.  

New Zealand relevance

Our climate change predictions indicate both increased drought and extreme rain events! Fortunately the soil infiltration and water holding benefits of CTF address both these key issues. While we typically have smaller farms, their productive value is higher.  So an equivalent percentage improvement from adoption CTF would have larger dollar gains per hectare.

CORS Networks

Australia is making a massive investment in CORS (Continuously Operating Reference Stations). These are permanent GPS signal correction systems that, for an annual subscription, provide RTK correction signals for use in mining, geology, agriculture and construction.  A statewide network in Victoria is 40% towards planned full coverage.  CORS networks offer some billions of dollars in savings over the expansion of private base station networks.  Many conference attendees thought farmers would continue to invest in their own, or local cooperative networks as well so these projections may be overly optimistic.  

Who went?

The usual suppliers of GPS equipment were evident.  There was considerable presence from Precision Agriculture farmer groups (South Australian No-Till Farming Association, Southern Precision Agriculture Association, Conservation Agriculture Association of Australia and NZ, LandWISE).  Private consultants, agronomists and Universities were also well represented.  Of some 83 delegates, 16 farmers were present.  Useful contacts were made on behalf of LandWISE. 

The experience of CTF farmers was that their CTF systems are delivering savings in fuel, fertiliser and time and improved yields and water use efficiency.  Continued extension of the use of CTF is likely, with other spatial technology bringing additional benefits to farmers who are choosing to adopt other Precision Agriculture systems on their farms.

Very brief headlines of the presentations are below.  Full information should be available soon on the ACTFA website – http://www.actfa.net

The Coming Famine: the risks to global food security – Julian Cribb (author of a book ‘The  Coming Famine’ to be published 2010)

Julian opened the conference by letting us know we are at crisis point. Many resources underpinning agriculture are running out.  Peak phosphorous has passed and the level of waste of nutrients in food production is huge.  He predicts major regional food crises leading to conflicts and mass refugee movements.  He sees food security as a national defence issue which suggests urgent diversion of defence spending into R&D for food production. see  http://www.sciencealert.com.au/features-global-food-crisis

CTF- The Proven Solution – Don Yule

Long time CTF proponent, Don showed how CTF is a solution to a host of resource management and productivity issues and that it offers gains in soil resilience to climate variability and social benefits. don@ctfsolutions.com.au

Cropping Systems for Climate Change – Jeff Tullberg

Jeff spoke on tillage and traffic options to improve rainfall use efficiency and soil surface protection, and the green house gas balance of cropping.  He says that CTF avoids the inefficiencies inherent in current systems and is a way forward to more productive and resilient cropping. jeff@ctfsolutions.com.au

Spatial Information Research – New Opportunities for Agriculture Communities – Phillip Collier

Spatial technologies support and promote improved farming practices and yield benefits.  The CRC (Cooperative Research Centre) for Spatial information is responsible for ‘spatially enabling Australia’. Agriculture, Natural Resources and Climate change are a focus of this CRC.  P.collier@unimelb.edu.au

What has CTF/Zero-Till done for my farming operation? – Robert Ruwoldt, Glenvale Farms

“Farmers resist change but there is always a better way to do things”     “Soil compaction is holding the world back from going to the next level”  Robert has achieved fewer weed problems, reduced fertiliser use and better water use efficiency since converting to CTF.  “Changing your farming system is the easiest thing to do, but some people make it the hardest” glenvalefarms@bigpond.com

The Farming Business 1992-2009 – Hugh Ball

A total of 15,000 hectares of arable cropping land is in the family business with a further 20,000 hectares under their management.  Key to this are capable core staff, external expertise and a family advisory board. CTF is on 3 meter centres, 12 m implements and 36-48 m boom sprayers. Balls are investing heavily in farming and CTF. “Money is cheap and the world is hungry” hugh@ballfm.com.au

Rural R&D Response – Peter Reading MD GRDC

Adoption by growers comes from Awareness, Tools and Motivation, if any of these elements are missing, adoption won’t happen.  Australian Precision Ag technology transfer is funded by GRDC via packages for growers and advisers in PA.  p.reading@grdc.com.au

Going Straight – A reporter’s run down the tramlines Peter Lewis ABC TV

A TV show on early CTF in 1998 captured Peter’s imagination.  He has enjoyed watching CTF evolve in Australia since then and passes on his enthusiasm for CTF as a non farmer. lewispeter@abc.net.au

A Contract Harvester Perspective on CTF – Peter Bradley

“If a farmer wants a profitable and more sustainable harvest… go for it- create your CTF system and you won’t look back”   Peter encourages his farmer clients to invest in  sustainable low emission cropping systems.  woolaroo@bigpond.com.au

Controlled Traffic Farming System – Australian CTF standard, Industry Proposal – Kevin Platz, John Deere

Initiatives to avoid problems of mismatching equipment include development of CTF standards.  Standards being agreed among farmers and key industry players include proposals for all tractors 150-500 HP to be at 3 m wheel tracks for CTF.  Manufacturing issues are still being discussed.  platzkevin@johndeere.com

Logistics and efficiency of grain harvest and transport systems Greg Butler – SANTFA

A model has been developed to assist grain farmers to reduce machine time, fuel consumption and emissions through better vehicle management. greg@santfa.com.au

Australian GNSS CORS networks – status, issues, challenges, future – Martin Hale

State CORS networks (on 70 km spacings) are at various stages of planning and installation and will offer sub 2 cm accuracy via GPS correction signals.  A national network (Auscope) is being implemented for science and commercial use.  Availability of correction signals to farmers, miners and the construction industry will be an additional benefits of the national network. martin.hale@dse.vic.gov.au

GNSS and Agriculture – Martin Nix, Navonix

This talk covered the national economic benefits of CORS networks vs local arrays of base stations. Benefits come from high accuracy, and using data multiple times and across multiple industries – mining construction, agriculture. Martin referred to ANZLIC and an Allen Consulting report, “The economic benefits of high resolution positioning.” http://www.crcsi.com.au/UPLOADS/PUBLICATIONS/PUBLICATION_348.pdf   martinjnix@gmail.com

Proximal Sensor Technologies – John Rochecouste CEO CAAANZ

Identifying the ‘production issue’ is still a precursor to the deployment of technology.  Farmers have the question, “How does the information relate to what I am doing?  What do we need to research and how do we manage data?  rochecouste@iinet.net.au

(We are interested to meet NZ members of the Conservation Agriculture Association of Australia and New Zealand.)

Remote Sensor Technologies – Eileen Perry DPI VIC

GPS is the enabling technology that allows farmers to fully utilise sensor data.   Selecting the most suitable sensor and mounting it on the most sensible platform (tractor, plane or satellite) is critical.   Using sensor data in combination with other information (e.g. yield, soil or crop data) is key to gaining the most benefit from sensor technology.  eileen.perry@dpi.vic.gov.au

Paul Slatter – John Deere Precision Ag specialist

Paul sees yield mapping as a key step in the Precision Agriculture data cycle.  When combined with input records of factors which influence yield, these show the rewards farmers are getting for their management decisions – varieties, dates, fertiliser etc. slatterpaul@johndeere.com

Gathering Data for Variable Rate Technology is the easiest bit, doing something with it is the challenge.  Ed Cay – gps-Ag

Australian farmers are using nutrient removal maps, water use efficiency, multilayer yield trends and gross margin maps to design and justify variable rate input spending.  Ed sees that the future for variable rate technology will bring easier to use hardware and software, more use of remote data transfer, service industry growth and more industry group support.  ed.cay@gps-ag.com.au

Agronomy, Controlled Traffic Systems, Precision Agriculture

Things that happen when your wheels turn – Is soil compaction flattening your profit and sustainability?

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As published in ‘Grower’, September 2009.

The invention of the wheel, is often raised as a measure of human progress. It has evolved from wood and stone, to steel and rubber. Once roads were formed and compacted for traffic, commerce and agriculture changed forever. Those with heavy loads to move had an option other than water, sled or legs. In agricultural cultivation, draught animals have been replaced by machinery which revolutionised crop production to keep pace with the food demand of a growing population.

The diameter, width and the softness of the tyre or surface, determine the footprint of any wheel.  That zone is where the pressure of load and vehicle is spread on soil or pavement – ‘where the rubber meets the road’. This footprint is an interesting place. It determines the quality of traction, wear and tear, and how well a vehicle or tractor can carry or pull a load. Here upward resistance equals the downward pressure of the wheel. If the surface is already compacted, little or no compaction will occur. If the surface is soft or loose, compaction is the result. Also rolling resistance and friction will increase on a soft surface. This increases the energy, and fuel consumption required to move, or reduces the load able to be carried.

Soil has some natural compaction which occurs with time, gravity, water movement and the passage of animals. Some consolidation of soil is desirable to prevent wind erosion and provide seed contact with soil for germination. Compaction can be an asset where repeated traffic is intended. (A lot of energy goes into compacting the base of our roads for instance). It is when the level of compaction of the soil affects the structural aggregates or peds in the soil, that structure and pore spaces are adversely affected.

In the growing zones of a crop, this is a problem. In a paddock or crop, the rolling wheel is riding on soil and vegetation. If the soil is soft the wheel is climbing onto loose material and rolling it down. In the process it is squeezing gas and water from the profile, closing pore spaces and making changes which can be longterm, and detrimental. Depending on the soil type and its state of dryness and existing compaction, around 75% of the undesirable effects of compaction can occur in the first pass.

In our cropping soil, when soil compaction is excessive, it can lead to the loss of structure, erosion, biological degradation and loss of water holding capacity and nutrients. In some regions of the world, compaction has led to the loss of productive capacity of soils and the departure of agriculture, probably forever. More commonly, compaction is a factor in reduced yields and deterioration of structure in cultivated soils. As land prices rise and our population increases, these soil quality trends will need to be reversed.

In next month’s Grower we will discuss how the use of GPS to guide machinery is containing compaction to traffic bearing zones, which are separate from the garden areas for growing the crop. This is allowing growers to reduce fuel consumption and other inputs and improve the profitability and sustainability of their cropping.

Controlled traffic farming (CTF) is all about managing soil compaction – confining it to narrow strips across the land and maximizing the remaining undamaged soil area for cropping. In practice CTF means matching machinery tracks so they take up the least possible area. Farm conversion to CTF is about adopting a CTF “mindset” – the belief that separating wheels and crops is a key method of reducing costs and increasing returns.