AgMemo Central Agricultural Region

Deep ripping in wet soils

An example of the ideal V shape produced from deep ripping sandy loam soils. DAFWA warns if a Y shape is formed, soils are still too wet to renovate, which could result in yield penalties.
An example of the ideal V shape produced from deep ripping sandy loam soils. DAFWA warns if a Y shape is formed, soils are still too wet to renovate, which could result in yield penalties.

Grain growers looking to take advantage of recent rainfall and start deep ripping paddocks are being warned their soils may still be too wet and they may do more harm than good.

Examine soils throughout paddocks thoroughly, before dragging the deep ripper across the whole program.

If the soil profile is too wet, machinery tines would move through the soil ‘like a knife through butter’, producing no soil renovation benefit.

The soil is not going to lift and shatter properly to loosen the whole soil profile, and is more likely to smear instead.

If deep ripping isn’t done properly, it is a waste of time and money. 

It can also have a negative effect on crop yields as there is the potential to compact the soil during the ripping process, reducing root growth and access to soil moisture during the season.

Deep ripping the top 35-50 centimetres of topsoil is typically undertaken to loosen hard layers of loamy sands to allow plant roots to access subsoil moisture, resulting in yield benefits that can last longer than two seasons, particularly when used in conjunction with controlled traffic farming.

There is a simple way to evaluate whether soils were still too wet for deep ripping.

Sample the soil at the depth to be ripped, and roll a handful of soil into a three millimetre diameter thin sausage to test the cohesion of the soil.

If you can roll the soil into a thin sausage and it maintains its shape, the clay-held moisture in the soil indicates it is too wet to rip.

Soils in this state will smear along the ripping line, making a hostile zone for root growth.

Another option is to rip a strip of a paddock and dig a hole behind the furrow rip to examine the breakout profile of the soil

The required shape is a V from the bottom to top of the ripping tine.

If the hole takes a Y shape, the soil is shattering from further up the tine and not the point. This creates horizontal compaction on the sides of the tine, damaging the soil profile and making it hard for roots to get through that lower section of the soil.

The department will continue its research on deep ripping this year, including examining different ripper set ups at the Mullewa Dryland Farmers’ Initiative field day on 23 March.

More information on the department’s deep ripping research is available on the Deep Ripping Soil Compaction

For more information contact Wayne Parker, Research Officer, Geraldton on +61(0)8 9956 8511.