HIGH fuel prices were not necessarily a reason to hold off deep ripping, according to analysis by the Department of Primary Industries and Regional Development (DPIRD).
DPIRD research scientist Bindi Isbister said with recent diesel price hikes and hard soils from a dry summer increasing fuel use, many growers were asking whether it was still worth deep ripping.
"Despite the high cost of fuel, if you are deep ripping a soil type that typically has a good yield response then it is still economically worthwhile," Ms Isbister said.
"For example, for a good sandplain that has a 600 kilogram per hectare wheat yield response, deep ripping is worthwhile.
"Even at a fuel cost of $3 per litre, with a wheat price of $330 per tonne, the additional return from deep ripping is $28/ha in the first year."
That number was based on the estimated cost of deep ripping to 55 centimetres for labour, wages and depreciation of $62/ha and a fuel use of 90L/ha.
"The benefit of deep ripping commonly persists for at least three years, therefore the cumulative three-year additional return is $183/ha with the ripping cost spread over that time," Ms Isbister said.
"If a minimal yield response is anticipated, for example 400kg/ha, and the optimal ripping costs are $132/ha at a fuel price of $2/L and wheat price of $330/t, then the cost of ripping is about the same as the returns from additional yield in the first year.
"In this case, a profitable response is dependent on the residual benefit of ripping in the second and third seasons, so it is a higher risk for more limited return."
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At Cunderdin, Kiara Harris and her father Elliot, run a deep ripping program every year and with the amount of sandy country they have, they can't afford to not chip away at it.
This year, a lack of rainfall meant they didn't have a great opportunity to rip as it was too dry, but they eventually worked about 200 hectares, which is half of what they normally try for, while a lot of other farmers were seeding canola.
Ms Harris said the fuel price definitely influenced their decision, but they also didn't really have the time or opportunity to do it.
"Those soils are really non-wetting and we're never going to get a good crop off them until we do something to the soil," she said.
"The more years we're not doing it, then the more years we're not making that extra profit and for us deep ripping seems to get the best results.
"We didn't want to go out and do a lot if we could afford to do it at a better opportunity, but we know it's always going to be a limiting factor on yield until we address the soil, so we made sure to get a bit done."
Ms Isbister analysed cereal grain yield responses to ripping at two different depths, 30-40cm and 55-60cm, incorporating data from historic and current DPIRD and Grains Research and Development Corporation trials.
She said due to limited summer rainfall in some regions the soil was very dry and hard, so it may not be possible to rip below the hard pan that typically extends to 60cm.
"Research has shown, particularly in low rainfall regions, if the hard pan is not removed completely due to shallow ripping, there can be a greater risk of the crop haying off early in a dry spring," she said.
"So if you intend to do the job, do it properly and rip deep enough to remove the subsoil compaction layer, or wait for another opportunity."
Some areas have received good rainfall over the past month which has provided an opportunity to effectively rip and remove those deeper hard pans, on responsive soil types.
With some growers leaving more fallow this year due to the high cost of inputs, it is a good opportunity to deep rip in spring when soil moisture is at an optimal level to achieve good ripping depth.
Ms Isbister said where possible, growers should avoid ripping rocky areas that increased the risk of machinery breakages, especially if using the same tractor for seeding.
"It is worthwhile for growers to do their own sums, taking into account the expected soil type response and cost of ripping to the optimum depth," she said.
