New research findings demonstrate a range of soil amelioration timings can be successful, but growers should take into account the potential for wind erosion if going early.
Department of Primary Industries and Regional Development (DPIRD) research scientist George Mwenda today (28 Feb) presented results from field experiments examining the impact of soil amelioration timing on crop yields at the Grains Research Update, Perth.
The research is supported with co-investment from the Grains Research and Development Corporation (GRDC) and DPIRD.
“We examined the effect of strategic deep tillage timing (from March to June) at Corrigin and Mingenew, on wheat and canola yield and found that grain yields from ameliorated treatments were similar irrespective of the timing of amelioration, for a given time of sowing,” Dr Mwenda said.
“However, wind erosion risk can vary from year to year and with soil type and site exposure, which should be carefully considered with early amelioration timing.
“Late soil amelioration and sowing (May-June, location specific) can reduce the risk of wind erosion but had lower grain yield compared to earlier amelioration timings (March-May), sown in mid-May.
“But short-season and well adapted short-mid season varieties can improve the performance of late amelioration timings, thereby reducing the yield loss associated with later sowing."
Dr Mwenda said for those interested in late amelioration, growers should still try to be seeding late ameliorated paddocks by mid-June if possible.
“If seeding at the end of May to mid-June, use a well-adapted, high yielding mid short wheat variety,” he said.
“If seeding after mid-June, consider using a well-adapted quick variety, especially in warmer shorter-season environments.”
The research also found that even with the yield penalty from late amelioration and sowing, wheat in late ameliorated treatments often yielded the same or higher than unameliorated treatments sown in the traditional mid-May window.
“Soil amelioration offset the delayed seeding, possibly because crops had greater access to subsoil moisture during grain filling in ameliorated soil,” Dr Mwenda said.
“Growers that ameliorate and sow wheat in June are unlikely to be worse off yield wise than those that did not ameliorate.
“While they miss out on some yield in the first season, compared to earlier ameliorations sown in mid-May, they will have considerably minimised their risk of exposure to wind erosion compared to the early amelioration timings.”
Dr Mwenda said a site at Corrigin raised some interesting results requiring further investigation around potential to recover yield losses from a late amelioration and seeding in the following season.
“Late amelioration can often occur when the soil is wet, erosion risk is reduced and also provides ample opportunity for knockdown sprays for weed control,” he said.
“This research is ongoing, but amelioration late in the sowing window, from end of May to mid June, is looking like a promising option for growers.”
The 2023 GRDC Grains Research Update ran at Crown Perth on February 27 and 28.
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