Farm Ireland

Wednesday 13 December 2017

Now we're sucking diesel

With diesel prices 35pc cheaper than last year, there's lots of potential to cut costs ahead of the peak season

Diesel prices are down 35pc compared to this time last year bringing relief to farmers and busy contractors.
Diesel prices are down 35pc compared to this time last year bringing relief to farmers and busy contractors.
With so much planting left to do, lower fuel prices are welcome news.
Derek Casey

Derek Casey

The price of a barrel of oil has a huge impact on everyday farming life, exerting influence on key inputs like diesel, fertiliser and even bale wrap. At this point the sustained fall in the price of oil has filtered through to diesel prices at the pump, but isn't it peculiar that the same can't be said for fertiliser prices?

Perhaps this is something the farm organisations should be investigating.

Lower diesel prices are fantastic news for this time of year - particularly as there is still so much planting left to do after the wet spring to date.

This week at the pumps farmers will pay on average €500 including VAT per thousand litres of agri diesel, depending on where in the country you are based. To put the drop into context, this same week last year agri diesel was priced at €780 per thousand litres including VAT.

That works out as a 35pc drop on last year's prices. Based on the figures in the table below comparing prices over the last two years, the potential is there to nicely reduce your fuel bill as we head into the part of the year where engines truly get going.

The news on falling fuel prices will be equally welcome to contractors. Silage is the big killer for diesel bills because it's such a power-hungry job. Maintaining some form of cash flow is now more important than ever; even a modestly sized contracting outfit can very quickly run up a fuel bill of €80,000 or €90,000.

Contractors need to have money coming in regularly to offset what is by far and away their biggest variable input cost. Remember that most logically minded farmers can usually be encouraged to pay earlier with a carrot approach of offering cheaper rates for upfront payment. Farmers will expect to see lower fuel prices reflected in contractor charges as well, though for their part contractors will argue that insurance premiums have risen again this year.

Whether you are farming or contracting, you can only improve what you can measure in the first instance. To this end it is worthwhile having an idea about the fuel requirements for some of the more power-hungry jobs like ploughing and power harrowing. Did you know that ploughing with a four furrow reversible plough, for example, tends to use on average 23 litres of diesel per hectare ploughed depending on the soil type? At current fuel prices this comes to a fuel cost per hectare ploughed of €11.50.

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Equally hard on the pocket is subsoiling, a job that many farmers do to relieve compaction caused either by poaching or machinery damage last backend. Subsoiling uses up about 18 litres of diesel per hectare worked, so about €9.00 at current diesel prices.

If these figures are coming as a surprise to you (see the table for fuel use for other common spring tasks), turn it to your advantage by tightening up on fuel costs. The beginning of spring is a good time to take stock of what your real fuel costs are and to plan to reduce unnecessary fuel use.

Some of the variables that have the most considerable effect on fuel consumption are also the easiest to manage. For example, tyre pressure selection is directly linked to excessive fuel consumption. Unnecessary use of counterweights is another fuel drain.

And correct tractor and tillage system selection are two other ways of managing fuel use.

Tractor choice

There are significant differences in fuel consumption rates between tractors, and data from the OECD tractor tests allow valid comparisons to be made. For these tests an individual tractor's fuel use is usually measured in something called grams per kilowatt hour (g/kWh).

Differences between tractor brands but for tractors of similar or the same power levels can be significant, so it is worth doing your homework the next time you are in the market for a new tractor. Obviously there are substantial cost implications for those tractors with poorer g/kWh ratings. Teagasc research has shown that, overall, the choice of tractor could easily account for fuel cost differences of up to €8/ha.

As regards the tillage system used, there are a number of different cultivation systems with various combinations of depth, tillage intensity, inversion and timing of operations.

Whether or not any system makes sense at current grain prices is for an argument outside of these pages. Regardless, at one extreme is the plough-based system with intensive secondary cultivation, while at the other is a direct drill system with a simple minimal disturbance disc coulter.

It is now accepted that minimum tillage establishment systems offer considerable scope for fuel saving because the shallower cultivation requires much less energy input per hectare. It is estimated that min till systems have a primary cultivation energy requirement of approximately 37pc of that required by ploughing.

In addition, the overall fuel use of a min till establishment system is just 50pc of that of conventional systems. This can result in a fuel saving of between €12 and €15 per hectare, with additional depreciation and repair costs accruing as well.

Is there a downside? Of course there is. Some are still nervous of min till systems because yields can be down compared to a conventional plough based approach.

But is the barometer for success yields or margin? It doesn't suit every soil type for sure, but with such attractive potential savings in fuel costs I'm surprised these systems haven't been taken up by more Irish farmers as of yet.

Tyre selection has a huge role to play especially in tillage farming. The importance of matching the tyres on your tractor to the work that it will be carrying out cannot be overstated.

Tyres are the conduits through which mechanical power is passed to the ground. How efficient the delivery of that power is depends on the condition and inflation pressure of the tyre.

Despite popular opinion, Michelin tests have demonstrated that tyre overinflation can lead to more of a fuel drain in field conditions, especially in tillage applications.

Overinflation leads to the tyre leaving a deeper "footprint" in the field and more diesel is burnt in the tractor's attempt to pull out of a deeper rut than is necessary to maintain traction.

The increased fuel consumption in this case is because of a bigger rolling resistance.

On the other hand, too low a tyre pressure is also a drain on diesel because the energy required to move the tractor and its load increases above and beyond what is required for good ground flotation practice. A balance must be reached.

As a rule of thumb, modern tractor tyres should have between three or four lugs on the ground. On the rear tyre of a typical 180hp tractor, in order to have three or four lugs on the ground at any given time the pressure should be just over 1 Bar - or 17psi in old money.

Contractors and farmers should check tyre pressure once a week at all times of the year but especially at this busy time in the fields.

If for some reason you anticipate your load will be changing significantly for a certain week (for example, if you are spreading slurry with a large tanker), then you can alter pressure as appropriate to suit.

Diesel prices are down 35pc compared to this time last year bringing relief to farmers and busy contractors.

With so much planting still to do, lower fuel prices are welcome news.

Indo Farming

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