Interface between technology and soil

30 Dec, 2011 02:00 AM
Mouldboard ploughing trials increased throughout the WA Wheatbelt this year on the back of promising trial data from the last two years.
Mouldboard ploughing trials increased throughout the WA Wheatbelt this year on the back of promising trial data from the last two years.

THE inexorable technology push continued in 2011 with more powerful machinery and faster and more sophisticated computer equipment for precision farming.

But while farmers were offered more horsepower and faster computer processing for a range of precision farming tasks, more interest focused on interfacing machinery and computers with the soil.

While we will continue to hear farmers talk about the need for increased productivity, hence big machinery, there is a growing focus on getting the soil right.

It is as important as ensuring you have the right levels before you start building.

To this end, farmer trials this year have involved machinery for mouldboarding, spading and deep tilling.

All three processes can be described as tools which form part of a system promoting sustainable farming.

Mullewa farmer Brad Smith, for example, established trials involving spading and liming, deep tillage, deep tillage followed by spading and liming with no cultivation.

He also is involved in so-called EM38 or EM farming with a view to employing variable product rates, to use money more efficiently.

"All our trials will tell us a story that combined with using EM38 technology, will help guide us in growing better crops," Brad said. "With EM38 we're aiming to even out the yields which means bringing up the poorer performing country.

"In some instances, what we discover through EM38 may well mean we excise some paddocks from the rotation and work on them using spading, deep tillage and soil ameliorants, to bring them back up to a productive state.

"Soil tests will be our guide to future strategies."

In the case of Mullewa farmers Charlie, Andrew and Rod Messina, it involved a mouldboard plough trial to create a paradigm shift in controlling resistant ryegrass populations and non-wetting sands.

The trials, also involving spading, were the result of exasperation of another dry year with poor crop germinations, and when it did rain, difficulty controlling ryegrass.

"We tried spading to overcome the water repellency issues but we also wanted good weed control and the mouldboard has delivered both," Rod said. "With the ryegrass results, our control trial revealed 900 ryegrass plants a square metre, the mouldboard achieved a 98 per cent kill of ryegrass while the spader trial showed a 43pc kill.

Doing their sums, it quickly became apparent to the family that using the mouldboard would eliminate pre-emergent spraying for hopefully least two years.

West Arrino farmer Tony Harding is considered one of the pioneers of mouldboard ploughing in WA and is negotiating with overseas companies to access more used mouldboard ploughs for WA farmers for 2012.

According to Tony, the cost of a plough is comparatively small in the fight to control weeds, promote soil structure, turn poor productive land into sustainable highly productive land and significantly reduce weed seed banks.

"Mouldboard ploughing is working for me and I'm getting higher cropping yields and less weeds and the bonus is I've eliminated non-wetting issues," he said.

On that score, Badgingarra farmer David Hayes, who was one of the first to introduce spading into WA, is continuing the process.

According to David, spading is working and he has no doubts mouldboard ploughing also is a tool to overcome non-wetting issues along with reducing weed seed burdens.

"The dramatic things farmers who have spaded are discovering, are promoting more uniform early crop and weed germinations, which basically give you a better chance to set up a profitable crop in non-wetting soils," he said.

"That essentially is the thing to remember.

"Spading is mostly a tool to overcome non-wetting issues which have become a real killer for so many farmers."

The Geraldton Department of Agriculture and Food also is involved in assessing different systems.

Research officer Stephen Davies is spearheading a major trial in the northern Wheatbelt to continue assessing deep tilling, spading and mouldboarding in concert with crop establishment employing knife points with wings, nude knife points (no attachments) and discs.

He will also trial banded surfactants as a means of overcoming water repellence in the seed row.

It is a trial agenda with a bit for everybody who is cropping loamy sands, sandy gravels and so-called pale deep sand (gutless).

And importantly, it is not just about the kind of tools you use.

As deep tillage aficionados have been saying for decades, it's about getting air and structure back into the soil.

According to Stephen, several trials over the last two years have shown deep ripping gives similar yield increases compared with rotary spading and mouldboard ploughing but in other instances mouldboard ploughing gave larger yield responses than deep tillage.

"It is apparent the yield benefits obtained were primarily a result of ameliorating subsoil compaction," he said.

"Responses to deep tillage can be variable and negative responses to tillage can occur in seasons with a dry finish but there can also be significant yield advantages as a result of removing compaction in better seasons."

And as the year drew to an end, Precision Agronomics Australia director Quenten Knight drew farmers' attention to the problems bigger machines are causing.

"Heavier equipment traffic over paddocks means heavier axle loadings," he said.

"As axle loadings increase, the depth of compaction increases and we're seeing hardpans forming down to 60cm (24in), so not even mouldboarding is getting rid of all the hardpans."

This story is being unwittingly exacerbated by clay spreading on sandy soils to remedy non-wetting soils.

"Firstly you have traffic from clay being spread, followed by smudging and then incorporating," Quenten said.

"The salient point is that 90 per cent of compaction occurs in the first pass and the soil can't repair itself.

"With deep tillage, roots have more accessibility to available subsoil moisture and in some cases, do it so well, plants can't hay off at the end of the season."

What Quenten suggests is that while deep tillage is the answer to fix historical compaction, you have to limit machinery traffic on the affected paddocks.

And the best way to do that is by tramlining, or controlled traffic (CT).

Stay tuned for the next revolution in machinery.

Date: Newest first | Oldest first


Matt Van Slyke
6/01/2012 6:42:53 AM, on Farm Weekly

Ironically, deep compaction is remedied by cereal ryes and annual ryegrasses rooting 60 to 150 cm that are either chemically killed 2-3 weeks before crop planting, or rolled/shredded for organic crop production. Your mouldboardiing oxidizes nutrients and destroys soil biology which leads to fast depletion of organic matter. Conservation tillers call it "mining". If you persist, you are well advised to replenish nutrients by at least planting cover crops off-season to help prevent costly soil erosion and nutrient leaching from watersheds going downstream which cause aquatic dead zones.


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