The Department of Primary Industries and Regional Development’s (DPIRD) encouraging findings were profiled at the Grains Research and Development Corporation (GRDC) 2024 Grains Research Update in Perth today.
The field research found ripping to 45 centimetres with topsoil inclusion plates lifted yields on the ripline compared with off the ripline by up to half a tonne per hectare or 66 per cent in a decile 1 dry season.
Research scientist Bindi Isbister said while the benefits of deep ripping were well known, the research confirmed anecdotal evidence that ripping with topsoil inclusion resulted in a big difference in plant growth when the crop is seeded on the ripline.
“In July 2023, paddock monitoring of a large-scale grower case study trial east of Geraldton observed that canola plants seeded on the ripline were much bigger than the plants seeded between or off the ripline,” she said.
“This sparked closer investigation of the soil properties to determine why the difference and if or where deep ripping was needed again, which is typically a four-year cycle of re-ripping.”
The research showed topsoil inclusion down the ripline created a pathway of better soil pH for roots to access deeper moisture and nutrients.
“There was greater root abundance down the ripping slot and into the non-acidic and non-aluminium toxic deeper subsoil, enabling the crop roots to extract more moisture than plants off the rip line,” Ms Isbister said.
“Soil bulk density to a depth of 20 to 50 centimetres also remained lower on the ripline four years after deep ripping with topsoil inclusion.
“There is higher organic carbon and root matter in the ripline, which could also help sustain and stablise the soil loosened by ripping, increasing the longevity of the ripping benefit.
Ms Isbister said subsequent deep ripping with topsoil inclusion in the off row could further lift and sustain the benefits of deep ripping.
“Re-ripping in the off row to alleviate compaction over a greater area of the paddock would improve pH, nutrition and organic matter, creating an inclusion zone every 30 centimetres,” she said.
“This gives each crop row close proximity to a ripline and access to better fertility and moisture each season – increasing yields and the longevity of the ripping benefit.”
The research, undertaken east of Geraldton, gives grain growers with yellow deep sands that range from fine to coarse sands confidence to invest in deep ripping and topsoil inclusion to improve productivity and profitability.
Ms Isbister will also discuss the research at the Yuna Regional Grain Research Update on Wednesday, 6 March 2024 at the Community Centre.
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