The Reefinator - Turning Rock into Soil

Aug 10,2017 at 08:18 am By Admin - Rocks Gone

The Reefinator - Turning Rock into Soil

Pierre Maartens - Farm Management Consultant, Planfarm.

Originally published in LANDLINE, May 2017.

Plain text version for ease of reading here, original document below. 

On many farms, there are paddocks with a percentage of soils consisting of hard conglomerate gravel and/or rock at the soil surface which make seeding a crop virtually impossible. For many years farmers have wished they had a solution for this problem to a) allow seeding to continue through these areas to optimise efficiency and b) to effectively establish a crop allowing a financial return off the area.

Well now there is a solution – the ‘Reefinator’ by Rocks Gone.

How does it work?

The Reefinator acts like a cheese grater by ripping the rock, however it stops large chunks coming up, due to the weight of the machine and a grate around the rippers’ teeth. To get through the grate it has to be smaller than a football and then it goes under the roller. After multiple passes the rock gets smaller and smaller and depth of soil left greater, achieving the desired result.

The Reefinator is able to rip and crush rock (most suitable to ironstone/coffee rock and shallow ironstone) below and above the ground, allowing crop to be planted on previously un-arable land. The end result is topsoil consisting typically of a mixture of soils and pea gravel which amounts to a good seed bed.

With efficiency around 1 ha/hour, but varying somewhat depending on the rock profile, it often takes two to three passes to get the maximum depth of soil/gravel.

Rocks Gone advise to get as big an area done in the first pass as possible and come back in later years for extra passes required however rock/soil type will ultimately determine which way to go. Users thus far have tackled the numbers of passes both within a season and across them.

Timing – the best time is Jan to March after summer rain.


Possible benefit/s of the Reefinator include:

  • Increasing crop yield on previously unproductive land. Yield benefits are variable, but generally speaking you will be increasing the potential of the poorest areas, which will result in the overall paddock average increasing.
  • In all cases the Reefinator will create soil depth where existing soil is shallow and rocky. In many cases the topsoil is too shallow to not only seed into but grow anything on. After working with the Reefinator it can be up to 15-25cm (subject to the rock/soil type and number of passes) which allows at least some crop rooting depth in turn allowing some sort of crop yield.
  • As a general rule though the greatest yield gains come on soils where the subsoil/rock/gravel is penetrable by crop roots but where the hard, impenetrable or shallow top soil has previously prevented crop establishment. On these soils crop rooting depth is effectively increased more than the working depth allowing for crop yields in excess of what is possible on a soil only 15-25cm deep.
  • Another bonus is improved water retention and less run-off (although in the summer of working the loosened, largely bare soil can temporarily be more vulnerable). This allows the roots to better utilise nitrogen and water as it moves down the soil profile (Delroy and Bowden, 1986).
  • Adding lime before using The Reefinator is a further way to improve the soil and importantly incorporate it at depth. This is especially the case for those soils where roots can penetrate into the subsoil which allows reasonable water holding capacity.
  • Improved working efficiency and thus reduced cost through straightening out run-lines and reducing overlap. For those that still seed round and round benefits will include less overlap also, primarily through less headlands.
  • Reduced wear and tear, plus associated downtime, when seeding on stony/rocky country. This benefit is always highlighted when discussing with those who have used the Reefinator at some scale and over a few years.
  • Improved pasture growth and therefore increased livestock carrying capacity.
  • Ultimately improving land value by converting previously un-arable land to arable. Farmland is valued on an arable basis and improving say 40 hectares from un-arable to arable at $1,000/ha means an equity improvement of $40,000.


The above benefits are obvious and, subject to the country renovated, quite significant, however the exercise is not a cheap one. So what are the economics of using a Reefinator to renovate stony/rocky country? How long until you recover the funds invested?

By way of example we have calculated the running cost per hour based on direct ownership and have included the ownership of Reefinator & tractor, fuel, wages, repairs/maintenance costs (which mainly includes replacing the points on the machine) and some incidentals.

We have assumed 400ha per year is carried out. As with all owner/operator operations the area of work carried out drives a large proportion of the cost/ha (scale).

It should be noted that wear rates are dependent on soil / rock type. In the example below we have worked on replacing one point per hour plus some incidental maintenance of the tractor and Reefinator.

Photo Credit: Mick McCagh


Tractor (assumed dedicated for this task)

$70 000.00


$120 000.00



Fuel (L)/Hour (based on tractor in picture above)


Fuel cost/L


Fuel cost/hour




The Reefinator Cost/ha - FINANCED OVER 5 YEARS (5%) - 400ha/year


Tractor cost/ha - FINANCED OVER 5 YERAS (5%) 400 ha/year


Repairs/ maintenance/ha


Other (inc insurance, licensing etc)


Total cost/ha



It should be noted that a variable from a cost perspective is the tractor. In many cases farmers are using their seeding tractor to pull the Reefinator. You will need at least a 350hp front wheel assist tractor to pull, the bigger the better. Users report that the work is hard on the tractor with general wear and tear greater than for other crop operations. In the above calculations we have assumed a dedicated, older tractor has been purchased for the job.


Yield improvements vary greatly depending on seasonal conditions and soil type (from 0kg/ha to greater than 1t/ha). Assuming a yield improvement of 300kg/ha and wheat price of $275/t it means additional income of $82.50/ha or a tad over three years to fully recover the funds invested. Of course, if the yield response is greater then funds invested are recovered quicker.


Photo Credit: Mick McCagh

Photo Credit: Mick McCagh

Yield improvement

Wheat Price

Return Period

300 kg


3.4 years

500 kg


2 years

1000 kg


1 year


The real yield responses will be soil type dependent remembering soil depth, as opposed to just working depth, will drive this.

Cost savings

In addition to the increased income there is the main benefit of less wear and tear on the air-seeder. With removed hard ridges making paddocks now effortless to work and less break out required. Although this is difficult to quantify there is a financial benefit of some sort.

Improved operating efficiency is the other area where there is a cost saving however this will be very dependent on the individual circumstances.

Land value improvement

As mentioned earlier in the article it is reasonable to assume that turning unarable land into arable land provides a ‘capital growth’ return to the landowner on top of the ‘dividend’ which is the extra profit derived off the area.

The exact degree of capital growth is not simple to quantify but logically it would be linked to the extra crop generated off the renovated area which will drive up average paddock yield which drives the land value as much as any factor!

Should I buy or contract out?

As with all operations the decision to owner/operate or contract out will largely come down to scale with cost/ha of ownership (Reefinator & Tractor) the cost most dictated by scale.

The other significant variable will be the ease of working (soil/rock type). In easier working country 2ha/hr is possible which halves the hourly rate based assumption.

To allow a comparison contract rates need to be known and this will vary across operators (bearing in mind this operation is a specialised one with not that many contractors currently out there). Planfarm’s research though suggests the following as typical of what is currently being charged.

Full contract inc fuel - $400-450/hr.

Hire of Reefinator only - $100/hr.

Key messages:

  • The Reefinator will cost up to $450/hr (full contract).
  • The decision to buy, hire or contract will be driven by scale and to a lesser degree ease of working. If the area to be tackled is large enough then, as per most crop operations, ownership will be cheapest.
  • Yield benefits are very soil type dependent.

Photo Credit: Mick McCagh

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Pierre Maartens - Farm Management Consultant, Planfarm.


Pierre was raised on a mixed farm south of Bloemfontein, South Africa. He completed his formal education in Bloemfontein with a tertiary degree in commerce which provided the first stepping stone to a career in banking. Pierre moved to Australia during 2004 and joined National Australia Bank in Bunbury then moved to Narrogin in 2008, specialising in Agricultural Banking in the Great Southern where he managed a wide range of clients including broad acre, livestock, feedlots, processing, small business and large business.

In January 2016, Pierre joined the Planfarm team based out of the Narrogin office.

Qualifications and Membership

Bachelor of Commerce (Economics) - (Free State University Bloemfontein South Africa, 1995)
Masters of Business Administration - (Free State University Bloemfontein South Africa, 2003)

Business Area

In his role as Farm Management Consultant, Pierre covers the following business areas:

Business analysis taking the physical and financial data from farm businesses and analysing this at key performance points to assist in the development of the business.
Budgeting projecting future cash flows to enable farmers to have a "business map" from which they can operate.
Benchmarking collecting the data from various clients and comparing the performance of individual farms against those in a similar rainfall zone.
Property purchases and leases financial analysis and projections relating to purchasing or leasing land.
Strategic planning assist farmers to develop long term plans from which they can make strategic business decisions.
Grain marketing provides general information.


Pierre has a young family that keeps him busy with their sporting and extra-curricular activities. He is a member of the Narrogin squash club still trying to get his "head around" AFL and supports the Eagles, also following rugby union and cricket.