Deep ripping investigated

The Grains Research and Development Corporation says opportunities may exist for growers to deep rip compacted soils in coming months.

Soil compaction costs WA agriculture an estimated $880 million a year and has been identified by the GRDC and Regional Cropping Solutions Networks as a priority issue for growers throughout the grainbelt.

Department of Agriculture and Food development officer Bindi Isbister said deep ripping was usually carried out in August after first rains.

“However, this can put pressure on machinery and staff as the tractor used for deep ripping is usually the same one used for seeding,” she said.

“If the deep ripper is strong enough and the tractor can get good traction, it can be more convenient to deep rip in conditions that are as dry as possible.”

Ms Isbister said the research project had been investigating methods to deep rip dry soil.

“Previous DAFWA/GRDC research has shown that a shallow leading tine design — where shallow tines are attached on a ripper ahead of and in line with deeper tines — can reduce draft requirements, fuel use and soil cloddiness,” she said.

“The work demonstrated that shallow leading tines can reduce draft force by up to 18 per cent when the leading tine works to a depth of 10cm on clay-textured soil, and by about 10 per cent on sandy soils.

“Using a weighted, or pressurised cage roller behind the ripper is essential to break up any clods and create an even seed bed.

“If ripping deeper in dry conditions, ripper widths of 4m-6m may be required to get enough traction to pull the ripper, particularly if ripping on commonly used 50cm row spacings.” Ms Isbister also said another benefit of ripping when soil moisture was low was the ability to use topsoil slotting plates that worked most effectively in the conditions.

“Ripping soils — especially those with high clay content — in wet conditions can smear the edges of the ripping line, reduce the effectiveness of ripping and restrict plant root exploration beyond the ripping slot,” she said.

“If you can roll a 3mm sausage of hand-moulded subsoil in your palms, it is probably too plastic and too wet to rip.”